Inflatable balloon and vessel diameter correlation system for intravascular lithotripsy devices

Abstract

A catheter system (100) for treating a treatment site (106) within or adjacent to a vessel wall (108A) of a blood vessel (108) includes a balloon (104), a first assembly illumination source (366), and a contact detector assembly (142). The balloon (104) is positionable substantially adjacent to the vessel wall (108A) at the treatment site (106). The balloon (104) has a balloon wall (130) that defines a balloon interior (146). The first assembly illumination source (366) generates a first assembly illumination beam (366B) that travels in a first direction (121F) toward the balloon interior (146). The contact detector assembly (142) is configured to optically analyze the first return energy beam (366R) traveling from the balloon interior (146) in a second direction (121S) opposite to the first direction (121F), and the contact detector assembly (142) is configured to analyze the first return energy beam (366R) to determine a contact state between the balloon wall (130) and the blood vessel wall (108A).

Description

[Background technology]

[0001] Vascular lesions within the body's blood vessels can be associated with an increased risk of serious adverse events such as myocardial infarction, embolism, deep vein thrombosis, stroke, etc. Severe vascular lesions can be difficult for physicians to treat and cure in a clinical setting.

[0002] Vascular lesions may be treated using interventions such as drug therapy, balloon angioplasty, atherectomy, stenting, and vascular graft bypass surgery, to name a few. Such interventions are not always ideal, and subsequent treatment may be necessary to address the lesion.

[0003] Angioplasty balloons are typically semi-compliant inflatable balloons (hereinafter also referred to as "balloons"), meaning that when pressure is applied to the balloon, the outer diameter of the balloon changes slightly. An "Instructions For Use" (IFU) manual is usually provided with each catheter, and within the IFU manual, a balloon compliance chart is usually provided. The balloon compliance chart plots the balloon's outer diameter against the balloon's internal pressure, allowing the physician to determine the balloon's outer diameter when pressure is applied. Because the IFU manual is not sterile, it is difficult for the physician to easily access the IFU manual during the procedure, as the physician must maintain asepsis. For this reason, the balloon compliance chart and / or IFU manual are often not used during the procedure.

[0004] Additionally, the outer diameter of the balloon is an important indicator for physicians to understand, as it must be properly sized relative to the inner diameter of the vessel in which the balloon is being used. Because the balloon wall must be in contact with the vessel wall to most effectively provide the desired lithotripsy therapy, accurately sizing the outer diameter of the balloon relative to the vessel's inner diameter allows for optimal energy delivery. If the balloon is not in contact with the vessel wall, the mechanical effectiveness of the energy delivery is significantly reduced. It should further be understood that excessive vessel stretching, which can occur when the balloon's outer diameter exceeds the vessel's inner diameter (as measured before the vessel is overstretched by the balloon), can be a safety concern that can result in serious vascular trauma, such as vessel laceration or dissection.

[0005] In many instances, intravascular lithotripsy (IVL) is performed within peripheral blood vessels prior to the subsequent use of a drug-coated balloon catheter (DCB). IVL therapy dissolves calcium, allowing the drug on the DCB catheter to penetrate into the fissure area and treat deep within the vessel wall, including delivering the drug to the adventitia (outermost wall). If the outer diameter of the DCB catheter is smaller than the inner diameter of the vessel wall, delivery of the drug on the DCB catheter may be reduced, resulting in insufficient therapeutic efficacy.

[0006] Several DCB clinical trials in below-the-knee (BTK) vessels have been unsuccessful, and it has been speculated that inappropriate balloon sizing may have contributed to the poor results. These studies used angiography (injection of a contrast agent into the vessel under fluoroscopy) to assess and measure vessel diameter. Other studies have shown that this method is inaccurate for measuring vessels, potentially resulting in errors of up to 1 millimeter (mm). Considering that some peripheral vessels have diameters ranging from 2 mm to 8 mm, this inaccuracy can be significant, resulting in discrepancies between the outer balloon diameter and the inner vessel diameter. This is particularly evident in BTK vessels, which have diameters ranging from 2 mm to 4 mm.

[0007] Based on the results of these studies, many physicians now use intravascular ultrasound (IVUS) and / or optical coherence tomography (OCT) catheters to measure vessel diameters to obtain accurate vessel morphology and size before using a DCB. These catheters are expensive, costing thousands of dollars for the procedure. Furthermore, catheter preparation, use, and interpretation of the results are time-consuming, significantly increasing procedure time. It also requires trained staff to use the diagnostic catheters and consoles. Summary of the Invention

[0008] The present invention relates to a catheter system for treating a treatment site within or adjacent to a vessel wall of a blood vessel. In various embodiments, the catheter system includes a balloon, a first assembly illumination source, and a contact detector assembly. The balloon is positionable substantially adjacent to the vessel wall at the treatment site. The balloon has a balloon wall defining a balloon interior. The first assembly illumination source generates a first assembly illumination beam traveling in a first direction toward the balloon interior. The contact detector assembly is configured to optically analyze a first return energy beam traveling from the balloon interior in a second direction opposite the first direction, and the contact detector assembly is configured to analyze the first return energy beam to determine a contact condition between the balloon wall and the vessel wall.

[0009] In many embodiments, the balloon is configured to receive and retain a catheter fluid within the balloon interior. In certain embodiments, the catheter system further includes a pressure sensor assembly including a pressure sensor configured to sense an internal balloon pressure of the catheter fluid within the balloon interior.

[0010] In some embodiments, the pressure sensor is in fluid communication with the catheter fluid held within the balloon interior. In certain embodiments, the pressure sensor is located within the interior of the balloon.

[0011] In some embodiments, the catheter system further includes a handle assembly coupled to the balloon, the handle assembly spaced apart from the balloon, the handle assembly usable by a user to operate the catheter system, and the pressure sensor disposed within the handle assembly.

[0012] In certain embodiments, the catheter system further includes a catheter shaft, the balloon being coupled to the catheter shaft, and the pressure sensor being disposed within the catheter shaft.

[0013] In some embodiments, the catheter system further includes a fluid pump that maintains catheter fluid introduced inside the balloon, and the pressure sensor is located within the fluid pump.

[0014] In certain embodiments, the catheter system further includes an inflation conduit for introducing catheter fluid into the interior of the balloon, and the pressure sensor is disposed within the inflation conduit. In some embodiments, the pressure sensor is selected from the group consisting of a fiber optic sensor, a diaphragm sensor, and a MEMS sensor.

[0015] In many embodiments, the catheter system further includes a balloon compliance chart that plots the outer diameter of the balloon against the internal balloon pressure, and a balloon diameter determination system that determines the outer diameter of the balloon based on the sensed internal balloon pressure and the balloon compliance chart.

[0016] In certain embodiments, the catheter system further includes a graphical user interface configured to visually display the outer diameter of the balloon. In various embodiments, the contact detector assembly is configured to analyze the first returning energy beam to determine when good contact exists between the balloon wall and the vessel wall.

[0017] In some embodiments, the catheter system further includes a vessel diameter determination system configured to determine an inner diameter of the vessel. In certain embodiments, if the contact detector assembly determines that good contact exists between the balloon wall and the vessel wall, the vessel diameter determination system determines that the inner diameter of the vessel is equal to the outer diameter of the balloon.

[0018] In some embodiments, the treatment site has a site length, and the vessel diameter determination system is configured to determine the inner diameter of the blood vessel at a plurality of locations along the site length of the treatment site. In certain embodiments, the locations along the length of the treatment area are spaced apart from one another by at least about 0.5 millimeters.

[0019] In some embodiments, the catheter system further includes a vessel diameter mapping system that includes an image of the treatment site in the vessel wall of the blood vessel, and the inner diameter of the blood vessel at multiple locations along the length of the treatment site is annotated on the image of the treatment site using the vessel diameter mapping system.

[0020] In certain embodiments, the catheter system further includes a graphical user interface configured to visually display (i) the outer diameter of the balloon and (ii) an image of the treatment site including annotations of the inner diameter of the vessel at multiple locations along the length of the treatment site.

[0021] In many embodiments, the catheter system further includes a system controller including one or more processors and a diameter matching system at least partially integrated within the system controller. In some embodiments, the diameter matching system is configured to utilize data from the balloon diameter determination system regarding the outer diameter of the balloon and data from the vessel diameter determination system regarding the inner diameter of the vessel at multiple locations along the length of the treatment site to ensure proper matching of the outer diameter of the balloon with the inner diameter of the vessel during use of the catheter system in a therapeutic procedure.

[0022] In certain embodiments, the system controller controls the internal balloon pressure of the catheter fluid inside the balloon to ensure proper matching of the outer diameter of the balloon with the inner diameter of the blood vessel when the catheter system is used in a therapeutic procedure.

[0023] In some embodiments, the catheter system further includes a beam guide, wherein the first assembly illumination beam travels in a first direction through the beam guide from a proximal end of the guide to a distal end of the guide disposed within the balloon, and the first return energy beam travels in a second direction through the beam guide from the distal end of the guide to the proximal end of the guide.

[0024] In certain embodiments, the first assembly illumination beam includes a first light energy and the first return energy beam includes a second light energy from at least a portion of the first light energy reflected from the vessel wall.

[0025] In many embodiments, the catheter system further includes a second assembly illumination source that generates a second assembly illumination beam that travels in a first direction toward the interior of the balloon. In some embodiments, the contact detector assembly is configured to optically analyze a second return energy beam that travels from the interior of the balloon in a second direction opposite the first direction, and the contact detector assembly is configured to analyze the first and second return energy beams to determine a contact condition between the balloon wall and the vessel wall.

[0026] In certain embodiments, the second assembly illumination beam travels in a first direction through the beam guide from the proximal end of the guide to the distal end of the guide positioned within the balloon interior, and the second return energy beam travels in a second direction through the beam guide from the distal end of the guide to the proximal end of the guide.

[0027] In some embodiments, the second assembly illumination beam includes first light energy and the second return energy beam includes second light energy from at least a portion of the first light energy from the second assembly illumination beam that is reflected from blood located between the balloon wall and the blood vessel wall.

[0028] In various embodiments, the first assembly illumination beam is at a first wavelength and the second assembly illumination beam is at a second wavelength that is different from the first wavelength. In certain embodiments, the first assembly illumination beam and the second assembly illumination beam are transmitted sequentially through the beam guide from the proximal end of the guide to the distal end of the guide.

[0029] In some embodiments, the first return energy beam travels in a second direction through the beam guide from the distal end of the guide to the proximal end of the guide, followed by the second assembly illumination beam traveling in the first direction through the beam guide from the proximal end of the guide to the distal end of the guide.

[0030] In other embodiments, the first assembly illumination beam and the second assembly illumination beam travel substantially simultaneously through the beam guide as a combined illumination beam from the proximal end of the guide to the distal end of the guide.

[0031] In some embodiments, the first return energy beam and the second return energy beam travel substantially simultaneously through the beam guide from the distal end of the guide to the proximal end of the guide as a combined return energy beam.

[0032] In many embodiments, the catheter system further includes an energy source that generates a light source beam that is directed inside the balloon. In some embodiments, the energy source is a light source.

[0033] In certain embodiments, the light source is an infrared laser. In some embodiments, the light source beam is directed through the beam guide from the proximal end of the guide to the distal end of the guide, which is disposed within the interior of the balloon.

[0034] In other embodiments, the catheter system further includes an energy guide separate from the beam guide, and the light source beam is directed through the energy guide from a proximal end of the guide to a distal end of the guide disposed within the balloon.

[0035] In some embodiments, the energy source is a light source and the energy guide is a light guide. In other embodiments, the energy source is a high voltage energy source that provides pulses of high voltage.

[0036] In certain embodiments, the energy guide includes an electrode pair including spaced apart electrodes extending within the balloon interior, and high voltage pulses from an energy source are applied to the electrodes to form an electric arc between the electrodes.

[0037] In some embodiments, the balloon interior is configured to receive and retain a catheter fluid within the balloon interior, and a light source beam directed toward the balloon interior induces the generation of plasma within the balloon interior.

[0038] In certain embodiments, the generation of plasma causes rapid bubble formation and imparts pressure waves to the balloon wall adjacent the treatment site. In many embodiments, the contact detector assembly includes a beam splitter and a photodetector, the beam splitter configured to receive return energy that has traveled through the beam guide in a second direction from the distal guide end to the proximal guide end and to direct at least a portion of the return energy to the photodetector.

[0039] In certain embodiments, the contact detector assembly further includes an optical element disposed along the beam path between the beam splitter and the photodetector, the optical element configured to couple a portion of the returned energy to the photodetector.

[0040] In some embodiments, the photodetector generates a signal based at least in part on the portion of the returned energy directed to the photodetector. In certain embodiments, the signal from the photodetector is amplified by an amplifier to provide an amplified signal that is directed to control electronics for determining the contact condition between the balloon wall and the vessel wall.

[0041] The present invention further relates to a method of treating a treatment site within or adjacent to a vessel wall of a blood vessel, the method including the steps of: positioning a balloon substantially adjacent to the vessel wall at the treatment site, the balloon having a balloon wall defining a balloon interior; generating a first assembly illumination beam with a first assembly illumination source; translating the first assembly illumination beam in a first direction toward the balloon interior; translating a first return energy beam from the balloon interior in a second direction opposite the first direction; and optically analyzing the first return energy beam from the balloon interior with a contact detector assembly to determine contact between the balloon wall and the vessel wall.

[0042] The present invention also relates to a catheter system for treating a treatment site within or adjacent to a heart valve, the catheter system including: a balloon positionable substantially adjacent to the heart valve at the treatment site, the balloon having a balloon wall defining a balloon interior; a first assembly illumination source generating a first assembly illumination beam moving in a first direction toward the balloon interior; and a contact detector assembly configured to optically analyze a first return energy beam from the balloon interior moving in a second direction opposite the first direction, the contact detector assembly configured to analyze the first return energy beam to determine a contact condition between the balloon wall and the heart valve.

[0043] The present invention further relates to a method for treating a treatment site within or adjacent to a heart valve, the method including the steps of: positioning a balloon at the treatment site substantially adjacent to the heart valve, the balloon having a balloon wall defining a balloon interior; generating a first assembly illumination beam with a first assembly illumination source; moving the first assembly illumination beam in a first direction toward the balloon interior; moving a first return energy beam from the balloon interior in a second direction opposite the first direction; and optically analyzing the first return energy beam from the balloon interior with a contact detector assembly to determine a contact condition between the balloon wall and the heart valve.

[0044] This Summary has outlined some of the teachings of the present application and is not intended to be an exclusive or exhaustive treatment of the present subject matter. Further details are found in the detailed description and appended claims. Other aspects will be apparent to those skilled in the art upon reading and understanding the following detailed description and viewing the drawings that form a part thereof, each of which should not be taken in a limiting sense. The scope herein is defined by the appended claims and their legal equivalents.

[0045] The novel features of this invention, as well as the invention itself, both as to its structure and its operation, will best be understood from the accompanying drawings taken in conjunction with the accompanying description, in which like reference characters refer to like parts. [Brief explanation of the drawings]

[0046] [Figure 1] FIG. 1 is a schematic cross-sectional view of one embodiment of a catheter system according to various embodiments herein, including an inflatable balloon having features of the present invention and a pressure sensor assembly and a vessel wall contact detector assembly usable as part of a vessel diameter correlation system (sometimes referred to herein as a "diameter correlation system"). [Figure 2]1 is a flow chart illustrating a first mode of operation of an embodiment of a catheter system including an embodiment of a vessel wall contact detector assembly. [Figure 3A] 3 is a simplified schematic diagram of a portion of an embodiment of a catheter system including an embodiment of a vessel wall contact detector assembly usable within a first mode of operation as described in connection with FIG. 2. [Figure 3B] 3B is a simplified schematic diagram of a portion of an embodiment of a catheter system including the embodiment of the vessel wall contact detector assembly shown in FIG. 3A, showing steps in a first mode of operation. FIG. [Figure 3C] 3B is a simplified schematic diagram of a portion of an embodiment of a catheter system including the embodiment of the vessel wall contact detector assembly shown in FIG. 3A, illustrating different steps in a first mode of operation. FIG. [Figure 3D] FIG. 3B is a simplified schematic diagram of a portion of an embodiment of a catheter system including the embodiment of the vessel wall contact detector assembly shown in FIG. 3A, illustrating further steps in a first mode of operation. [Figure 3E] FIG. 3B is a simplified schematic diagram of a portion of an embodiment of a catheter system including the embodiment of the vessel wall contact detector assembly shown in FIG. 3A, illustrating further steps in a first mode of operation. [Figure 3F] FIG. 3B is a simplified schematic diagram of a portion of an embodiment of a catheter system including the embodiment of the vessel wall contact detector assembly shown in FIG. 3A, illustrating further steps in a first mode of operation. [Figure 4] 3B is a flowchart illustrating a second mode of operation of an embodiment of a catheter system including an embodiment of the vessel wall contact detector assembly of FIG. 3A. [Figure 5A] 3B is a simplified schematic diagram of a portion of an embodiment of a catheter system including the embodiment of the vessel wall contact detector assembly of FIG. 3A, showing steps in a second mode of operation. [Figure 5B]3B is a simplified schematic diagram of a portion of an embodiment of a catheter system including the embodiment of the vessel wall contact detector assembly of FIG. 3A, showing different steps in a second mode of operation. [Figure 5C] FIG. 3B is a simplified schematic diagram of a portion of an embodiment of a catheter system including the embodiment of the vessel wall contact detector assembly shown in FIG. 3A, illustrating further steps in a second mode of operation. [Figure 6] 10 is a flow chart illustrating a mode of operation of another embodiment of a catheter system including another embodiment of a vessel wall contact detector assembly. [Figure 7A] 7 is a simplified schematic diagram of a portion of an embodiment of a catheter system including an embodiment of a vessel wall contact detector assembly usable within the mode of operation as described in connection with FIG. 6. [Figure 7B] 7B is a simplified schematic diagram of a portion of an embodiment of a catheter system including the embodiment of the vessel wall contact detector assembly shown in FIG. 7A, showing steps in an operational mode. [Figure 7C] 7B is a simplified schematic diagram of an embodiment of a catheter system including the embodiment of the vessel wall contact detector assembly shown in FIG. 7A, showing different steps in an operational mode. [Figure 7D] FIG. 7B is a simplified schematic diagram of a portion of an embodiment of a catheter system including the embodiment of the vessel wall contact detector assembly shown in FIG. 7A, illustrating yet another step in an operational mode. [Figure 8] FIG. 10 is a simplified schematic diagram of yet another embodiment of a catheter system including yet another embodiment of a vessel wall contact detector assembly. [Figure 9]FIG. 1 is a simplified schematic diagram of an embodiment of a diameter correlation system having features of the present invention, incorporating inputs from and / or outputs to a pressure sensor assembly, a balloon compliance chart, a balloon diameter determination system, a vessel wall contact detector assembly, a vessel diameter determination system, and a vessel diameter mapping system. [Figure 10] 10 is a flow chart illustrating a first (test and / or mapping) mode of operation of the radial correlation system of FIG. 9; [Figure 11A] 10A-10C are images illustrating a method for ensuring proper placement of the catheter, balloon, and / or emitter of the catheter system relative to the treatment site. [Figure 11B] FIG. 10 shows an image showing the entire length of a treatment site with markings at specific periodic locations along the length, showing the inner diameter of the vessel at those locations as part of a vessel diameter mapping system. [Figure 12] 10 is a flow chart illustrating a second (therapeutic use) mode of operation of the diameter correlation system of FIG. 9. DETAILED DESCRIPTION OF THE INVENTION

[0047] While embodiments of the present invention are susceptible to various modifications and alternative forms, specific examples thereof have been shown by way of example and drawings and are herein described in detail. It is understood, however, that the scope of the present specification is not limited to the particular embodiments described. On the contrary, the intent is to cover modifications, equivalents, and alternatives included within the spirit and scope of the present specification.

[0048] Treating vascular lesions at treatment sites within a patient's body can reduce serious adverse events or deaths in affected subjects. As referred to herein, a serious adverse event is an event that can occur anywhere within the body due to the presence of a vascular lesion. Serious adverse events include, but are not limited to, serious adverse cardiac events, serious adverse events in the peripheral or central vasculature, serious adverse events in the brain, serious adverse events in the muscular system, or serious adverse events in any of the internal organs.

[0049] In various embodiments, the catheter systems and related methods disclosed herein can include a catheter configured to advance to a vascular lesion, such as a calcified or fibrous vascular lesion, located at a treatment site within a patient's body. As used herein, a "treatment site" can be located at or near the vascular wall of a patient's blood vessel. For example, in some embodiments, a "treatment site" can be located in a below-the-knee (BTK) vasculature, which can have a longer site length (sometimes up to 30 centimeters or more) and a relatively narrow inner diameter that can vary along the site length. In other embodiments, a "treatment site" can be located at or near the vascular wall of another patient's blood vessel. Additionally or alternatively, a "treatment site" can be at or near a patient's heart valve. Additionally or alternatively, a "treatment site" can be at another suitable location within a patient's body.

[0050] Furthermore, as used herein, the terms "intravascular lesion," "vascular lesion," and "treatment site" are used interchangeably unless otherwise noted. Intravascular lesions and / or vascular lesions may also be referred to herein simply as "lesions."

[0051] Those skilled in the art will realize that the following detailed description of the present invention is illustrative only and is not intended to be in any way limiting. Other embodiments of the present invention will readily suggest themselves to such skilled artisans having the benefit of this disclosure. Reference will now be made in detail to embodiments of the present invention as illustrated in the accompanying drawings.

[0052] In the interest of clarity, not all of the routine features of the implementations described herein are shown and described. Of course, it will be recognized that in developing any such actual implementation, numerous implementation-specific decisions will need to be made to achieve the developer's particular goals, including meeting application- and commercial-related constraints, and that these particular goals will vary from implementation to implementation and from developer to developer. Moreover, it will be recognized that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking of engineering for those of ordinary skill in the art having the benefit of this disclosure.

[0053] The catheter systems disclosed herein can include a variety of configurations. Referring now to FIG. 1 , a schematic cross-sectional view of a catheter system 100 according to various embodiments is shown. In some embodiments, the catheter system 100 is adapted to apply pressure waves to one or more treatment sites within or adjacent to a vessel wall of a blood vessel or on or adjacent to a heart valve within a patient's body to induce fragmentation. In certain implementations, the catheter system 100 is adapted to deliver a drug to the vessel wall in the form of an anti-inflammatory agent, an anti-tumor agent, an anti-angiogenic agent, or the like.

[0054] 1 , the catheter system 100 includes (i) a catheter 102 including one or more of an inflatable balloon 104 (sometimes referred to herein as a “balloon”), a catheter shaft 110, a guidewire 112, an energy guide bundle 122 including one or more energy guides 122A, a source manifold 136, a fluid pump 138, a handle assembly 128, and a pressure sensor assembly 141 including one or more pressure sensors 141S, and (ii) a system console 123 including one or more of an energy source 124, a power supply 125, a system controller 126, a graphic user interface 127 (“GUI”), and a vessel wall contact detector assembly 142 (sometimes referred to as a “contact detector assembly” or “contact detector”). Alternatively, the catheter system 100, catheter 102, and / or system console 123 may include more or fewer components than those specifically shown and described in connection with FIG. 1 .

[0055] Catheter 102 is configured to navigate to treatment site 106 at any suitable location within body 107 of patient 109. In some embodiments, treatment site 106 may be within or adjacent to a vessel wall 108A of a blood vessel 108 within body 107 of patient 109. Alternatively, in other embodiments, catheter 102 may be used at treatment site 106 within or adjacent to a heart valve within body 107 of patient 109.

[0056] As shown, the treatment site 106 can have a site length 106L, which can be any suitable or desired length. For example, the site length 106L can be up to 30 centimeters or more, for example, when the treatment site 106 is in a below-the-knee (BTK) vasculature. Alternatively, the treatment site 106 can have another suitable site length 106L.

[0057] The treatment site 106 may include one or more vascular lesions 106A, such as, for example, calcified vascular lesions. Additionally or alternatively, the treatment site 106 may include vascular lesions 106A, such as fibrous vascular lesions. It should be understood that the vascular lesions 106A present in the treatment site 106 help define the site length 106L of the treatment site 106.

[0058] In certain embodiments, the balloon 104 may be coupled to a catheter shaft 110. The balloon 104 may include a balloon proximal end 104P and a balloon distal end 104D. The catheter shaft 110 may extend from a proximal portion 114 of the catheter system 100 to a distal portion 116 of the catheter system 100. The catheter shaft 110 may include a longitudinal axis 144. The catheter 102 and / or catheter shaft 110 may also include a guidewire lumen 118 configured to travel over a guidewire 112. As utilized herein, the guidewire lumen 118 defines a conduit through which the guidewire 112 extends. The catheter shaft 110 may further include an internal inflation cavity (not shown) and / or various other internal cavities for various other purposes. In some embodiments, the catheter 102 can have a distal end opening 120 that can accommodate and track over the guidewire 112 as the catheter 102 is moved and positioned at or near the treatment site 106. In some embodiments, the balloon proximal end 104P can be coupled to the catheter shaft 110 and the balloon distal end 104D can be coupled to the guidewire lumen 118.

[0059] The balloon 104 includes a balloon wall 130 that defines a balloon interior 146. The balloon 104 can be selectively inflated with a catheter fluid 132 to expand from a deflated state suitable for advancing the catheter 102 through the patient's vasculature to an inflated state (as shown in FIG. 1 ) suitable for anchoring the catheter 102 in place relative to the treatment site 106. In other words, when the balloon 104 is in the inflated state, the balloon wall 130 of the balloon 104 is configured to be positioned substantially directly adjacent to and / or in contact with the treatment site 106. While FIG. 1 illustrates the balloon wall 130 of the balloon 104 as being spaced apart from the treatment site 106 of the blood vessel 108 when in the inflated state, it should be understood that this is done solely for ease of explanation. It is understood that the balloon wall 130 of the balloon 104 is typically substantially directly adjacent and / or abutting or contacting the treatment site 106 when the balloon 104 is in an inflated state, as desired.

[0060] In many embodiments, the present invention discloses systems and methods for accurately estimating balloon diameter and vessel diameter, thus ensuring a desired correlation between the outer diameter 104BD of the balloon 104 and the inner diameter 108D of the blood vessel 108, to provide enhanced therapeutic efficacy during use of an intravascular lithotriptor and / or drug-coated balloon catheter in a time- and cost-effective manner. In other words, the present invention discloses systems and methods for ensuring that the balloon wall 130 of the balloon 104 is substantially directly adjacent to and / or abuts or contacts the vessel wall 108A of the blood vessel 108 at the treatment site 106 when the balloon 104 is in an inflated state. It should be understood that the systems and methods disclosed herein are equally applicable when the catheter system 100 is utilized as an intravascular lithotriptor for the purpose of pulverizing vascular lesions 106A at the treatment site 106, and / or when the catheter system 100 is utilized as a drug-coated balloon catheter for the purpose of delivering drug therapy to the treatment site 106 for treating deep within the vascular wall 108A of the blood vessel 108.

[0061] In summary, in many embodiments, the system controller 126 may utilize data and / or information from a pressure sensor assembly 141, such as one or more pressure sensors 141S, and a contact detector assembly 142 as part of a balloon-vessel diameter correlation system 147 (illustrated as a box located within the system controller 126 and sometimes also referred to herein as the "diameter correlation system") to ensure proper correlation and / or matching between the outer diameter 104BD of the balloon 104 and the inner diameter 108D of the vessel 108 for the most effective lithotripsy therapy and / or drug delivery at the treatment site 106. In particular, system controller 126 (i) utilizes data and / or information from pressure sensor assembly 141 regarding the internal balloon pressure, such as from one or more pressure sensors 141S, along with a balloon compliance chart 955 (shown in FIG. 9) that plots the outer diameter 104BD of balloon 104 against the internal balloon pressure, to determine the outer diameter 104BD of balloon 104 as part of a balloon diameter determination system 957 (shown in FIG. 9), and (ii) utilizes data and / or information from balloon diameter determination system 957 regarding the outer diameter 104BD of balloon 104 to determine the inner diameter 108D of blood vessel 108, to determine the inner diameter 108D of blood vessel 108, along with data and / or information from balloon diameter determination system 957 regarding the outer diameter 104BD of balloon 104, to determine the inner diameter 108D of blood vessel 108, along with data and / or information from balloon diameter determination system 958 (shown in FIG. 9). (iii) utilizes data and / or information from a vessel diameter determination system 958 at multiple locations along the site length 106L of the treatment site 106 as part of a vessel diameter mapping system 959 (shown in FIG. 9 ); and (iv) utilizes data and / or information from the vessel diameter mapping system 959 as part of a diameter correlation system 147, together with data and / or information from the balloon diameter determination system 957, to increase the likelihood of obtaining a proper correlation (or match) between the outer diameter 104BD of the balloon 104 and the inner diameter 108D of the blood vessel 108 for the most effective lithotripsy and / or drug delivery at the treatment site 106.

[0062] It is understood that when the balloon 104 is positioned adjacent the treatment site 106 of the blood vessel 108, it is desirable for little or no blood 305 (e.g., as illustrated in FIG. 3A ) or other fluid to be present between the balloon wall 130 and the vessel wall 108A. Unfortunately, if the balloon 104 is not properly sized—for example, if the balloon 104 is too small for the vessel 108 being treated, or if the balloon 104 is not properly inflated—a certain amount of blood 305 may be present between the balloon wall 130 and the vessel wall 108A, which may adversely affect the energy delivery and therapeutic effect of the catheter system 100. Accordingly, the contact detector assembly 142 of the present invention may be utilized to detect whether the balloon wall 130 is in optimal contact with the vessel wall 108A, so that energy delivery and therapeutic effect may be optimized.

[0063] Balloons 104 suitable for use in the catheter system 100 include those that, when in a deflated state, are capable of passing through the vasculature of a patient 109. In some embodiments, the balloon 104 is made from silicone. In other embodiments, the balloon 104 may be made from polydimethylsiloxane (PDMS), polyurethane, a polymer such as PEBAX™ material, nylon, or other suitable material.

[0064] Balloon 104 can have any suitable diameter (in an inflated state). In various embodiments, balloon 104 can have a diameter (in an inflated state) ranging from less than 1 millimeter (mm) up to 25 mm. In some embodiments, balloon 104 can have a diameter (in an inflated state) ranging from at least 1.5 mm to a maximum of 14 mm. In certain embodiments, balloon 104 can have a diameter (in an inflated state) ranging from at least 2 mm to a maximum of 5 mm.

[0065] In some embodiments, the balloon 104 can have a balloon length 104L ranging from at least 3 mm to 300 mm. More specifically, in some embodiments, the balloon 104 can have a balloon length 104L ranging from at least 8 mm to 200 mm. It should be understood that a balloon 104 having a relatively longer length can be positioned adjacent to a larger treatment site 106 and, therefore, can be used to apply pressure waves to a larger vascular lesion 106A or multiple vascular lesions 106A at a precise location within the treatment site 106 to induce fragmentation. It should further be understood that a longer balloon 104 can also be positioned adjacent to multiple treatment sites 106 at any one time. It should also be understood that if the site length 106L of the treatment site 106 is very long, such as up to 30 cm or more in a below-the-knee (BTK) vasculature, the balloon 104 may need to be moved to multiple different positions during a procedure to effectively treat the entire site length 106L of the treatment site 106.

[0066] The balloon 104 is pressurized to approximately 1 atmosphere (atm) (1.013 x 10 5 Pa) ~ 70 atm (70.928 × 10 5 In some embodiments, the balloon 104 can be inflated to an inflation pressure of at least 20 atm (20.265×10 Pa). 5 Pa) ~ 60 atm (60.795 × 10 5 In other embodiments, the balloon 104 can be inflated to an inflation pressure of at least 6 atm (6.0795×10 Pa). 5 Pa) ~ 20 atm (20.265 × 10 5 In yet another embodiment, the balloon 104 can be inflated to an inflation pressure of at least 3 atm (3.0398×10 Pa). 5 Pa) ~ 20 atm (20.265 × 10 5 In yet another embodiment, the balloon 104 can be inflated to an inflation pressure of at least 2 atm (2.0265×10 Pa). 5 Pa) ~ 10 atm (10.1325 × 10 5 It can be inflated to an inflation pressure of 100 Pa.

[0067] It should be understood that, as described herein, the inflation pressure of the balloon 104 (also referred to as the "internal balloon pressure") affects the outer diameter 104BD of the balloon 104 and, therefore, as part of the diameter correlation system 147, affects the appropriate correlation between the outer diameter 104BD of the balloon 104 and the inner diameter 108D of the blood vessel 108.

[0068] The balloon 104 can have a variety of shapes, including, but not limited to, conical, square, rectangular, spherical, conical / square, conical / spherical, expanded spherical, elliptical, tapered, bone-shaped, stepped diameter, offset, or conical offset. In some embodiments, the balloon 104 can include a drug-eluting coating or a drug-eluting stent structure. The drug-eluting coating or drug-eluting stent can include one or more therapeutic agents, including anti-inflammatory agents, anti-tumor agents, anti-angiogenic agents, etc.

[0069] The catheter fluid 132 used to inflate the balloon 104 can be a liquid or a gas. Some examples of catheter fluids 132 suitable for use include, but are not limited to, one or more of water, saline, contrast agent, a gas such as a fluorocarbon, a perfluorocarbon, carbon dioxide, or other suitable catheter fluids 132. In some embodiments, the catheter fluid 132 can be used as a base inflation fluid. In some embodiments, the catheter fluid 132 can include a mixture of saline and contrast agent in an approximately 50:50 volume ratio. In other embodiments, the catheter fluid 132 can include a mixture of saline and contrast agent in an approximately 25:75 volume ratio. In yet other embodiments, the catheter fluid 132 can include a mixture of saline and contrast agent in an approximately 75:25 volume ratio. However, it should be understood that any suitable ratio of saline to contrast agent can be used. The catheter fluid 132 can be adjusted based on its composition, viscosity, etc., to appropriately control the propagation speed of the pressure wave. In certain embodiments, catheter fluids 132 suitable for use herein are biocompatible. The volume of catheter fluid 132 can be adjusted depending on the energy source 124 selected and the type of catheter fluid 132 used.

[0070] In some embodiments, the contrast agent used in the contrast medium can include, but is not limited to, an iodine-based contrast agent, such as an ionic or non-ionic iodine-based contrast agent. Some non-limiting examples of ionic iodine-based contrast agents include diatrizoate, metrizoate, iothalamate, and ioxaglate. Some non-limiting examples of non-ionic iodine-based contrast agents include iopamidol, iohexol, ioxilan, iopromide, iodixanol, and ioversol. In other embodiments, non-iodine-based contrast agents can be used. Suitable non-iodine-containing contrast agents can include gadolinium(III)-based contrast agents. Suitable fluorocarbon and perfluorocarbon agents can include, but are not limited to, agents such as the perfluorocarbon dodecafluoropentane (DDFP, C5F12).

[0071] The catheter fluid 132 can include absorbers that selectively absorb light in the ultraviolet (e.g., at least 10 nanometers (nm) to 400 nm), visible (e.g., at least 400 nm to 780 nm), or near-infrared (e.g., at least 780 nm to 2.5 μm) regions of the electromagnetic spectrum. Suitable absorbers include those that have an absorption maximum across a spectrum of at least 10 nm to 2.5 μm. Alternatively, the catheter fluid 132 can include absorbers that selectively absorb light within the mid-infrared (e.g., at least 2.5 μm to 15 μm) or far-infrared (e.g., at least 15 μm to 1 mm) regions of the electromagnetic spectrum. In various embodiments, the absorbers can have an absorption maximum that corresponds to the emission maximum of a laser used in the catheter system 100. By way of non-limiting example, various lasers that can be used in the catheter system 100 include a neodymium:yttrium-aluminum-garnet (Nd:YAG emission maximum=1064 nm) laser, a holmium:YAG (Ho:YAG emission maximum=2.1 μm) laser, or an erbium:YAG (Er:YAG emission maximum=2.94 μm) laser. In some embodiments, the absorber may be water soluble. In other embodiments, the absorber is not water soluble. In some embodiments, the absorber used in the catheter fluid 132 can be tailored to match the peak emission of the energy source 124. Various energy sources 124 having emission wavelengths of at least 10 nanometers to 1 millimeter are described elsewhere herein.

[0072] The catheter shaft 110 of the catheter 102 may be coupled to one or more energy guides 122A of the energy guide bundle 122 in optical communication with the energy source 124. The energy guide(s) 122A may be disposed along the catheter shaft 110 within the balloon 104. Each of the energy guides 122A may have a guide end 122D at any suitable longitudinal position relative to the balloon length 104L of the balloon 104 and / or relative to the length of the guidewire lumen 118.

[0073] In some embodiments, each energy guide 122A can be an optical fiber and the energy source 124 can be a laser. The energy source 124 can be in optical communication with the energy guides 122A at the proximal section 114 of the catheter system 100. More specifically, the energy source 124 can be in selective, simultaneous, sequential, and / or alternating optical communication with each of the energy guides 122A in any desired combination, order, and / or pattern.

[0074] In some embodiments, the catheter shaft 110 may be coupled to multiple energy guides 122A, such as a first energy guide, a second energy guide, a third energy guide, etc., which may be positioned at any suitable location around and / or relative to the guidewire lumen 118 and / or catheter shaft 110. For example, in certain non-limiting embodiments, two energy guides 122A are positioned approximately 180 degrees apart from one another around the circumference of the guidewire lumen 118 and / or catheter shaft 110, three energy guides 122A are positioned approximately 120 degrees apart from one another around the circumference of the guidewire lumen 118 and / or catheter shaft 110, four energy guides 122A are positioned approximately 90 degrees apart from one another around the circumference of the guidewire lumen 118 and / or catheter shaft 110, and five energy guides 122A are positioned approximately 180 degrees apart from one another around the circumference of the guidewire lumen 118 and / or catheter shaft 110. For example, six energy guides 122A may be spaced approximately 72 degrees apart from one another around the circumference of the guidewire lumen 118 and / or catheter shaft 110, six energy guides 122A may be spaced approximately 60 degrees apart from one another around the circumference of the guidewire lumen 118 and / or catheter shaft 110, eight energy guides 122A may be spaced approximately 45 degrees apart from one another around the circumference of the guidewire lumen 118 and / or catheter shaft 110, or ten energy guides 122A may be spaced approximately 36 degrees apart from one another around the circumference of the guidewire lumen 118 and / or catheter shaft 110. Further alternatively, the multiple energy guides 122A need not be uniformly spaced from one another around the circumference of the guidewire lumen 118 and / or catheter shaft 110. More specifically, it should be further understood that the energy guides 122A may be uniformly or non-uniformly spaced around the guidewire lumen 118 and / or catheter shaft 110 to achieve a desired effect at a desired location.

[0075] In certain embodiments, guidewire lumen 118 can have a grooved outer surface, with a plurality of grooves extending generally longitudinally along guidewire lumen 118. In such embodiments, each of energy guides 122A can be disposed, housed, and retained within an individual groove formed along and / or within the outer surface of guidewire lumen 118. Alternatively, guidewire lumen 118 can be formed without a grooved outer surface, and the position of energy guide 122A relative to guidewire lumen 118 can be maintained by another suitable method.

[0076] The catheter system 100, catheter 102, and / or energy guide bundle 122 can include any number of energy guides 122A in optical communication with the energy source 124 at the proximal portion 114 and in optical communication with the catheter fluid 132 in the balloon interior 146 of the balloon 104 at the distal portion 116. For example, in some embodiments, the catheter system 100, catheter 102, and / or energy guide bundle 122 can include from one energy guide 122A to more than 30 energy guides 122A. The guide end 122D of each energy guide 122A can be located at any suitable or desired longitudinal position within the balloon interior 146 relative to the balloon length 104L of the balloon 104. Alternatively, in other embodiments, the catheter system 100, catheter 102, and / or energy guide bundle 122 can include more than 30 energy guides 122A.

[0077] The energy guide 122A can have any suitable design that is useful and suitable for enabling the generation of plasma and / or pressure waves within the catheter fluid 132 within the balloon interior 146. Accordingly, the general description of the energy guide 122A as a light guide is not intended to be limiting in any way, except as set forth in the claims appended hereto. More specifically, although the catheter system 100 is often described as including the energy source 124 as a light source and one or more energy guides 122A as light guides, the catheter system 100 can alternatively include any suitable energy source 124 and energy guides 122A for enabling the desired generation of plasma within the catheter fluid 132 within the balloon interior 146. For example, in one non-exclusive alternative embodiment, the energy source 124 can be configured to provide high-voltage pulses, and each energy guide 122A can include an electrode pair including spaced-apart electrodes extending into the balloon interior 146. In such embodiments, pulses of high voltage are applied to the electrodes, forming an electric arc between the electrodes, thereby generating a plasma and creating pressure waves in the catheter fluid 132 that are utilized to impart a disruptive force to the vascular lesion 106A at the treatment site 106. Further alternatively, the energy source 124 and / or energy guide 122A can have another suitable design and / or configuration, such as electrical, acoustic, pneumatic, other mechanical, etc.

[0078] As shown, the catheter system 100 can include one or more emitters 135 configured to generate plasma and / or pressure waves in the catheter fluid 132 within the balloon interior 146. Each emitter 135 includes a guide end 122D of one of the energy guides 122A disposed within the balloon interior 146 and a corresponding plasma-generating structure 133 (also referred to herein as a "plasma generator") disposed proximate to, but typically spaced from, the guide end 122D. Energy from the energy source 124 is directed toward, received by, and guided through the energy guide 122A before being emitted from the guide end 122D of the energy guide 122A. The energy emitted from the guide end 122D is directed toward, and incident on, the corresponding plasma generator 133, activating the plasma generator 133 to generate plasma within the catheter fluid 132 within the balloon interior 146.

[0079] In certain embodiments, emitter 135 can be formed from and / or include a radiopaque material that is readily visible when used with fluoroscopy during an intravascular lithotripsy procedure. Visibility of emitter 135 through the use of a radiopaque material allows a user or operator to more precisely position emitter 135 substantially adjacent to vascular lesion 106A, if desired, and / or selectively activate only emitters 135 positioned closest to vascular lesion 106A to more effectively fragment vascular lesion 106A. Alternatively, emitter 135 can be formed from other suitable materials that are visible to a user or operator during an intravascular lithotripsy procedure.

[0080] By positioning the emitters 135 more accurately substantially adjacent to the vascular lesion 106A at the treatment site 106, and by activating only certain emitters 135 based on their proximity to the vascular lesion 106A at the treatment site 106, the user or operator can operate the catheter system 100 more effectively and efficiently. Thus, the user and operator can realize cost and resource savings.

[0081] In certain embodiments, the energy guide 122A may include an optical fiber or a flexible light pipe. The energy guide 122A may be thin and flexible, allowing an optical signal to be transmitted with little loss of intensity. The energy guide 122A may include a core surrounded by a cladding. In some embodiments, the core may be a cylindrical core or a partially cylindrical core. The core and cladding of the energy guide 122A may be formed from one or more materials, including, but not limited to, one or more types of glass, silica, or one or more polymers. The energy guide 122A may also include a protective coating, such as a polymer. It should be understood that the refractive index of the core is greater than the refractive index of the cladding.

[0082] Each energy guide 122A can direct a first energy along its length from the proximal guide end 122P toward the distal guide end 122D, which has at least one optical window (not shown) located within the balloon interior 146. In some embodiments, the first energy can originate from the energy source 124 and be directed along the energy guide 122A from the proximal guide end 122P to the distal guide end 122D into the balloon interior 146. The first energy originating from the energy source 124 can be utilized to perform a therapeutic procedure with the catheter system 100 to treat and / or destroy the vascular lesion 106A at the treatment site 106. In other implementations, the first energy can originate from one or more assembly illumination sources 366, 368 (or simply "illumination sources," as shown, for example, in FIG. 3A ) that can be included as part of the contact detector assembly 142. As described in more detail below, a first energy generated from the irradiation sources 366, 368 may be used to irradiate an area at or near the guide end 122D and / or at or near the treatment site 106, thereby generating a second energy at or near the treatment site 106 that may then be utilized by the contact detector assembly 142 to determine the state of contact between the balloon wall 130 and the vessel wall 108A.

[0083] In various embodiments, the guide distal end 122D of each energy guide 122A can include and / or incorporate a terminal optical receiver 122R, which is a structure disposed at or near the guide distal end 122D of the energy guide 122A and configured to capture and / or receive the second energy and allow the second energy to travel back into and through the energy guide 122A from the guide distal end 122D to the guide proximal end 122P. In other words, the first energy can travel in a first direction 121F along the energy guide 122A generally from the guide proximal end 122P toward the guide distal end 122D of the energy guide 122A. The second energy, which may, in certain circumstances, include at least a portion of the first energy, may travel in a second direction 121S along the energy guide 122A that is substantially opposite to the first direction 121F, such as from at or near the distal guide end 122D of the energy guide 122A toward the proximal guide end 122P. Additionally, as described in more detail herein below, the second energy emitted from the proximal guide end 122P after traveling back through the energy guide 122A (in the second direction 121S) may be isolated and then optically detected, interrogated, and / or analyzed through the use of the contact detector assembly 142 to determine whether the balloon wall 130 of the balloon 104 is in optimal contact with the vessel wall 108A of the blood vessel 108 at the treatment site 106.

[0084] The energy guide 122A can have a variety of configurations around and / or relative to the catheter shaft 110 of the catheter 102. In some embodiments, the energy guide 122A can extend parallel to the longitudinal axis 144 of the catheter shaft 110. In some embodiments, the energy guide 122A can be physically coupled to the catheter shaft 110. In other embodiments, the energy guide 122A can be disposed along the length of the outer diameter of the catheter shaft 110. In still other embodiments, the energy guide 122A can be disposed within one or more energy guide lumens within the catheter shaft 110.

[0085] The multiple energy guides 122A may also be positioned at any suitable location around the guidewire lumen 118 and / or catheter shaft 110, and the guide end 122D of each of the multiple energy guides 122A may be positioned at any suitable longitudinal position relative to the balloon length 104L of the balloon 104 and / or relative to the length of the guidewire lumen 118 to more effectively and precisely apply pressure waves to destroy vascular lesions 106A at the treatment site 106.

[0086] In certain embodiments, the energy guide 122A can include one or more optoacoustic transducers 154, and each optoacoustic transducer 154 can be in optical communication with the energy guide 122A within which the optoacoustic transducer 154 is disposed. In some embodiments, the optoacoustic transducer 154 can be in optical communication with the guide end 122D of the energy guide 122A. In such embodiments, the optoacoustic transducer 154 can have a shape that corresponds to and / or matches the guide end 122D of the energy guide 122A.

[0087] The photoacoustic transducer 154 is configured to convert the first energy into acoustic waves at or near the guide end 122D of the energy guide 122A, and the direction of the acoustic waves can be adjusted by changing the angle of the guide end 122D of the energy guide 122A.

[0088] In certain embodiments, the opto-acoustic transducer 154 disposed at the guide end 122D of the energy guide 122A can have the same shape as the guide end 122D of the energy guide 122A. For example, in certain non-exclusive embodiments, the opto-acoustic transducer 154 and / or the guide end 122D can have a conical shape, a convex shape, a concave shape, a bulbous shape, a square shape, a stepped shape, a semicircular shape, an oval shape, and the like. The energy guide 122A can further include additional opto-acoustic transducers 154 disposed along one or more sides of the length of the energy guide 122A.

[0089] In some embodiments, the energy guide 122A can further include one or more deflecting structures or “deflectors” (not shown in FIG. 1 ) disposed within the energy guide 122A and / or near the guide distal end 122D of the energy guide 122A and configured to direct energy from the energy guide 122A toward a side surface located at or near the guide distal end 122D of the energy guide 122A before the energy is directed toward the balloon wall 130. The deflecting structures can include any structure in the system that deflects energy from the energy guide 122A from an axial path through the energy guide 122A toward a side surface of the energy guide 122A. Each of the multiple energy guides 122A can include one or more optical windows disposed along a longitudinal or circumferential surface of the respective energy guide 122A and in optical communication with the deflecting structures. In other words, the turning structure can have any suitable structural form configured to direct energy within energy guide 122A toward guide distal end 122D or a side surface proximate guide distal end 122D, the side surface being in optical communication with the optical window. The optical window can include a portion of energy guide 122A that allows energy to exit energy guide 122A from within energy guide 122A, such as a portion of energy guide 122A that is free of cladding material on or around energy guide 122A.

[0090] Examples of deflecting structures suitable for use include reflective elements, refractive elements, and fiber diffusers. Deflecting structures suitable for focusing the first energy outward from the tip of the energy guide 122A can include, but are not limited to, those with convex surfaces, gradient-index (GRIN) lenses, and mirror-focus lenses. Upon reaching the deflecting structure, the first energy can be deflected within the energy guide 122A to one or more of a plasma generator 133 positioned near, but typically spaced from, the guide end 122D of the energy guide 122A, and an optoacoustic transducer 154 in optical communication with a side of the energy guide 122A. In use, the plasma generator 133 receives the first energy emitted from the guide distal end 122D of the energy guide 122A and generates a plasma in the catheter fluid 132 within the balloon interior 146, resulting in the generation of plasma bubbles and / or pressure waves that can be directed outward from the sides of the energy guide 122A toward the balloon wall 130. Additionally or alternatively, in use, the photoacoustic transducer 154 converts optical energy into acoustic waves that propagate outward from the sides of the energy guide 122A.

[0091] The source manifold 136 can be located at or near the proximal section 114 of the catheter system 100. The source manifold 136 can include one or more proximal openings that can receive one or more energy guides 122A of the energy guide bundle 122, the guidewire 112, and / or an inflation conduit 140 that is coupled in fluid communication with a fluid pump 138. The catheter system 100 can also include a fluid pump 138 configured to inflate the balloon 104 with catheter fluid 132 as needed.

[0092] As noted above, in the embodiment shown in Figure 1, the system console 123 includes one or more of the energy source 124, the power source 125, the system controller 126, the GUI 127, and the contact detector assembly 142. Alternatively, the system console 123 may include more or fewer components than those specifically shown in Figure 1. For example, in certain non-exclusive alternative embodiments, the system console 123 may be designed without the GUI 127. Further alternatively, one or more of the energy source 124, the power source 125, the system controller 126, the GUI 127, and the contact detector assembly 142 may be provided within the catheter system 100 without the specific need for a system console 123.

[0093] 1, in certain embodiments, at least a portion of diameter correlation system 147 and contact detector assembly 142 may be located substantially within system console 123. Alternatively, components of diameter correlation system 147 and / or contact detector assembly 142 may be arranged in a manner different from that specifically shown in FIG.

[0094] As shown, the system console 123 and the components included therein are operably coupled to the catheter 102, the energy guide bundle 122, and the remainder of the catheter system 100. For example, in some embodiments, as shown in FIG. 1 , the system console 123 can include a console connection port 148 (sometimes commonly referred to as a “socket”) by which the energy guide bundle 122 is mechanically coupled to the system console 123. In such embodiments, the energy guide bundle 122 can include a guide connection housing 150 (which can generally include one or more ferrules) that houses a portion of each of the energy guides 122A, such as the guide proximal end 122P. At least a portion of the guide connection housing 150 is configured to fit and selectively retain within the console connection port 148 to provide a mechanical connection between the energy guide bundle 122 and the system console 123 and to contribute to providing an optical coupling between the energy source 124 and the energy guides 122A of the energy guide bundle 122.

[0095] The energy guide bundle 122 may also include a guide bundler 152 (or "shell") that brings each of the individual energy guides 122A closer together so that the energy guides 122A and / or the energy guide bundle 122 may be in a more compact form when extending into the blood vessel 108 as part of the catheter 102 during use of the catheter system 100.

[0096] The energy source 124 may optionally and / or alternatively be coupled in optical communication with each of the energy guides 122A, such as the proximal guide end 122P of each of the energy guides 122A in the energy guide bundle 122. Specifically, the energy source 124 may be configured to generate a first energy in the form of a light source beam 124A, such as a pulsed light source beam, which may optionally and / or alternatively be directed to and received as individual guide beams 124B at each of the energy guides 122A in the energy guide bundle 122. Alternatively, the catheter system 100 may include two or more energy sources 124. For example, in one non-exclusive alternative embodiment, the catheter system 100 may include a separate energy source 124 for each of the energy guides 122A in the energy guide bundle 122.

[0097] The energy source 124 can have any suitable design. In certain embodiments, the energy source 124 can be configured to provide a submillisecond pulse of first energy from the energy source 124, where the submillisecond pulse of first energy is focused to a small spot for coupling to the proximal guide end 122P of the energy guide 122A. Such a pulse of first energy is then directed and / or guided along the energy guide 122A to a location within the balloon interior 146 of the balloon 104, thereby inducing plasma formation (sometimes referred to herein as a “plasma flash”) within the catheter fluid 132 within the balloon interior 146 of the balloon 104, such as via a plasma generator 133, which may include and / or incorporate structure located at or near the distal guide end 122D of the energy guide 122A. In many embodiments, the plasma generator 133 can be positioned slightly spaced from the distal guide end 122D of the energy guide 122A. In certain embodiments, the plasma generator 133 is provided in the form of a backstop-type structure having an inclined surface that can redirect energy emitted from the guide end portion 122D toward the balloon wall 130 of the balloon 104 and / or toward the vessel wall 108A of the blood vessel 108 at the treatment site 106.

[0098] Specifically, first energy emitted at guide distal end 122D of energy guide 122A is directed toward and irradiates and activates material in plasma generator 133, such as material on the inclined surface of plasma generator 133, to generate plasma within catheter fluid 132 within balloon interior 146. The plasma generation ionizes and superheats the surrounding catheter fluid 132, thereby causing rapid inertial bubble formation and transmitting pressure waves to treatment site 106. An example of a plasma-induced bubble 134 is shown in FIG.

[0099] The plasma generator 133 may be formed from any suitable material. For example, in certain non-exclusive embodiments, the plasma generator 133 may be formed from one or more metals and / or metal alloys having relatively high melting temperatures, such as titanium, stainless steel, tungsten, tantalum, platinum, molybdenum, niobium, and iridium. Alternatively, the plasma generator 133 may be formed from at least one of magnesium oxide, beryllium oxide, tungsten carbide, titanium nitride, titanium carbonitride, and titanium carbide. Furthermore, the plasma generator 133 may be formed from at least one of diamond CVD and diamond. In other embodiments, the plasma generator 133 may be formed from a transition metal, a metal alloy, or a ceramic material. Furthermore, in some embodiments, the plasma generator 133 may be formed at least partially from a polymer, a polymeric material, and / or a plastic (such as polyimide and nylon). Furthermore, the plasma generator 133 may be formed from any other suitable material.

[0100] In various non-exclusive alternative embodiments, the sub-millisecond pulses of first energy from the energy source 124 can be delivered to the treatment site 106 at a frequency between about 1 Hertz (Hz) and 5000 Hz, between about 30 Hz and 1000 Hz, between about 10 Hz and 100 Hz, or between about 1 Hz and 30 Hz. Alternatively, the sub-millisecond pulses of first energy can be delivered to the treatment site 106 at a frequency that can be greater than 5000 Hz or less than 1 Hz, or any other suitable range of frequencies.

[0101] It should be understood that although the energy source 124 is typically utilized to provide a first pulse of energy, the energy source 124 may still be described as providing a single source beam 124A that is a single pulsed source beam.

[0102] Suitable energy sources 124 for use can include various types of light sources, including lasers and lamps. For example, in certain non-exclusive embodiments, the energy source 124 can be an infrared laser that emits the first energy in the form of pulses of infrared light. Alternatively, as discussed above, the energy source 124 can include any suitable type of energy source.

[0103] Suitable lasers include short-pulse lasers on the sub-millisecond time scale. In some embodiments, the energy source 124 can include a laser on the nanosecond (ns) time scale. Lasers can also include short-pulse lasers on the picosecond (ps), femtosecond (fs), and microsecond (μs) time scales. It should be understood that there are many combinations of laser wavelengths, pulse widths, and energy levels that can be used to generate plasma within the catheter fluid 132 of the catheter 102. In various non-exclusive alternative embodiments, pulse widths can include those falling within a range including at least 10 ns to 3000 ns, at least 20 ns to 100 ns, or at least 1 ns to 500 ns. Alternatively, any other suitable pulse width range can be used.

[0104] Exemplary nanosecond lasers can include those in the UV to IR spectrum, spanning wavelengths from approximately 10 nanometers (nm) to 1 millimeter (mm). In some embodiments, the energy source 124 suitable for use in the catheter system 100 can include those capable of generating light with wavelengths of at least 750 nm to 2000 nm. In other embodiments, the energy source 124 can include those capable of generating light with wavelengths of at least 700 nm to 3000 nm. In still other embodiments, the energy source 124 can include those capable of generating light with wavelengths of at least 100 nm to 10 micrometers (μm). Nanosecond lasers can include those having repetition rates of up to 200 kHz.

[0105] In some embodiments, the laser can include a Q-switched thulium:yttrium-aluminum-garnet (Tm:YAG) laser, hi other embodiments, the laser can include a neodymium:yttrium-aluminum-garnet (Nd:YAG) laser, a holmium:yttrium-aluminum-garnet (Ho:YAG) laser, an erbium:yttrium-aluminum-garnet (Er:YAG) laser, an excimer laser, a helium-neon laser, a carbon dioxide laser, and a doped pulsed fiber laser.

[0106] In yet other embodiments, the energy source 124 can include multiple lasers grouped in series. In yet other embodiments, the energy source 124 can include one or more low-energy lasers fed into a high-energy amplifier, such as a master oscillator power amplifier (MOPA). In yet other embodiments, the energy source 124 can include multiple lasers combined in parallel or series to provide the energy necessary to generate plasma bubbles 134 within the catheter fluid 132.

[0107] The catheter system 100 can generate pressure waves having maximum pressures in the range of at least 1 megapascal (MPa) to 100 MPa. The maximum pressure generated by a particular catheter system 100 depends on the energy source 124, the absorber material, the bubble expansion, the propagation medium, the balloon material, and other factors. In various non-exclusive alternative embodiments, the catheter system 100 can generate pressure waves having maximum pressures in the range of at least about 2 MPa to 50 MPa, at least about 2 MPa to 30 MPa, or at least about 15 MPa to 25 MPa.

[0108] The pressure waves may be applied to the treatment site 106 at a radial distance from the energy guide 122A within a range of at least about 0.1 millimeters (mm) to greater than about 25 mm when the catheter 102 is positioned at the treatment site 106. In various non-exclusive alternative embodiments, the pressure waves may be applied to the treatment site 106 at a radial distance from the energy guide 122A within a range of at least about 10 mm to 20 mm, at least about 1 mm to 10 mm, at least about 1.5 mm to 4 mm, or at least about 0.1 mm to 10 mm when the catheter 102 is positioned at the treatment site 106. In other embodiments, the pressure waves may be applied to the treatment site 106 at another suitable distance different from the aforementioned ranges. In some embodiments, the pressure waves may be applied to the treatment site 106 at a distance of at least about 0.1 mm to 10 mm in a range of at least about 2 MPa to 30 MPa. In some embodiments, the pressure waves may be applied to the treatment site 106 at a distance of at least about 0.1 mm to 10 mm in a range of at least about 2 MPa to 25 MPa. Further alternatively, other suitable pressure ranges and distances may be used.

[0109] Power supply 125 is electrically coupled to and configured to provide the necessary power to each of energy supply source 124, system controller 126, GUI 127, handle assembly 128, pressure sensor assembly 141, and contact detector assembly 142. Power supply 125 may have any suitable design for such purpose.

[0110] The system controller 126 is electrically coupled to and receives power from the power source 125. The system controller 126 is connected and configured to control the operation of each of the energy supply source 124, the GUI 127, the pressure sensor assembly 141, and the contact detector assembly 142. The system controller 126 may include one or more processors or circuits for controlling the operation of at least the energy supply source 124, the GUI 127, the pressure sensor assembly 141, and the contact detector assembly 142. For example, the system controller 126 may control the energy supply source 124 to generate a first pulse of energy as desired and / or at any desired radial rate. The system controller 126 may also control the internal balloon pressure in cooperation with the pressure sensor assembly 141 and the balloon compliance chart 955 to control and / or determine the outer diameter 104BD of the balloon 104, for example, as part of a balloon diameter determination system 957. The system controller 126 further controls and / or operates in conjunction with the contact detector assembly 142 to effectively provide real-time, continuous monitoring of the positioning of the balloon 104 relative to the vascular wall 108A of the blood vessel 108 to ensure that adequate and desired contact exists between the balloon wall 130 and the vascular wall 108A before a first energy is delivered from the energy source 124 through the energy guide 122A into the balloon interior 146 for the purpose of treating and / or destroying an intravascular lesion 106A at the treatment site 106.

[0111] In various embodiments, system controller 126 may also be configured to control and / or monitor algorithms that control the operation of diameter correlation system 147. In certain embodiments, the algorithms of diameter correlation system 147 may be substantially embedded within system controller 126.

[0112] Additionally, the system controller 126 may be configured to control the operation of other components of the catheter system 100, such as positioning the catheter 102 and / or the guide distal end 122D of the energy guide 122A adjacent the treatment site 106, inflation of the balloon 104 with catheter fluid 132, etc. Additionally or alternatively, the catheter system 100 may include one or more additional controllers, which may be arranged in any suitable manner, for purposes of controlling various operations of the catheter system 100. For example, in certain embodiments, the additional controllers and / or portions of the system controller 126 may be located and / or incorporated within the handle assembly 128.

[0113] The GUI 127 is accessible by a user or operator of the catheter system 100. The GUI 127 is electrically connected to the system controller 126. With such a design, the GUI 127 can be used to ensure that the user or operator is effectively utilizing the catheter system 100 to apply pressure and induce fragmentation at the treatment site(s) 106. The GUI 127 can provide the user or operator with information available before, during, and after use of the catheter system 100. For example, the GUI 127 can be used to communicate to the user or operator information obtained through operation of the diameter correlation system 147, including information from the pressure sensor assembly 141, the contact detector assembly 142, the balloon diameter determination system 957, the vessel diameter determination system 958, and the vessel diameter mapping system 959. In one embodiment, the GUI 127 can provide static visual data and / or information to the user or operator. Additionally or alternatively, the GUI 127 may provide dynamic visual data and / or information to the user or operator, such as video data or any other data that changes over time during use of the catheter system 100. In various embodiments, the GUI 127 may include one or more colors, different sizes, variable brightness, etc., which may serve as alerts to the user or operator. Additionally or alternatively, the GUI 127 may provide audio data or information to the user or operator. The details of the GUI 127 may vary depending on the design requirements of the catheter system 100 or the particular needs, specifications, and / or desires of the user or operator.

[0114] 1, the handle assembly 128 may be located at or near the proximal portion 114 of the catheter system 100 and / or near the source manifold 136. In this embodiment, the handle assembly 128 is coupled to and spaced apart from the balloon 104. Alternatively, the handle assembly 128 may be located in another suitable location.

[0115] The handle assembly 128 is handled and used by a user or operator to manipulate, position, and control the catheter 102. The design and specific features of the handle assembly 128 can be varied to suit the design requirements of the catheter system 100. In the embodiment illustrated in FIG. 1 , the handle assembly 128 is separate from, but in electrical and / or fluid communication with, one or more of the system controller 126, the energy supply 124, the fluid pump 138, the GUI 127, the pressure sensor assembly 141, and the contact detector assembly 142.

[0116] In some embodiments, the handle assembly 128 can integrate and / or include at least a portion of the system controller 126 within the handle assembly 128. For example, as shown, in certain such embodiments, the handle assembly 128 can include circuitry 156 that is electrically connected between the catheter electronics and the system console 123 and can constitute at least a portion of the system controller 126. In some embodiments, the circuitry 156 can receive electrical signals or data from the pressure sensor assembly 141 and / or the contact detector assembly 142. Additionally or alternatively, the circuitry 156 can transmit such electrical signals or otherwise provide data to the system controller 126.

[0117] In one embodiment, circuitry 156 may include a printed circuit board having one or more integrated circuits, or any other suitable circuitry. In alternative embodiments, circuitry 156 may be omitted or may be included within system controller 126, and circuitry 156 may, in various embodiments, be located external to handle assembly 128, such as within system console 123. It should be understood that handle assembly 128 may include fewer or additional components than those specifically illustrated and described herein.

[0118] The pressure sensor assembly 141 includes one or more pressure sensors 141S configured to sense and / or monitor the internal balloon pressure of the catheter fluid 132 held within the balloon interior 146 of the balloon 104 during operation of the catheter system 100. More specifically, the pressure sensor assembly 141 and / or pressure sensor 141S can provide real-time, continuous monitoring of the internal balloon pressure within the balloon interior 146 in conjunction with electronics or optics that may be included in the handle assembly 128 and / or the system console 123. The pressure sensor assembly 141 and / or pressure sensor 141S can generate a sensor signal or output related to the sensed internal balloon pressure and provide the sensor output to a system controller 126 configured to control various operations of the catheter system 100. The system controller 126 can control the internal balloon pressure in order to control the outer diameter 104BD of the balloon 104 through the use of a balloon compliance chart 955 for the particular type, size, design, material, etc. of the balloon 104 used in the catheter system 100. Thus, this sensing and / or monitoring of the internal balloon pressure by the pressure sensor assembly 141 and / or pressure sensor 141S provides the user or operator with useful information regarding the performance, reliability, and safety of the catheter system 100. For example, the sensed internal balloon pressure may be utilized in combination with a balloon compliance chart 955, which plots the outer diameter of the balloon against the internal balloon pressure, to determine the outer diameter 104BD of the balloon 104. The outer diameter 104BD of the balloon 104 may then be displayed on the GUI 127, thus allowing the user or operator to keep track of the outer diameter 104BD of the balloon 104 during the procedure.

[0119] It should be understood that the one or more pressure sensors 141S of the pressure sensor assembly 141 may be positioned at any suitable location within the catheter system 100 so as to be in fluid communication with the catheter fluid 132 within the balloon interior 146. For example, in certain non-exclusive embodiments, as shown, the one or more pressure sensors 141S of the pressure sensor assembly 141 may be positioned at one or more of the handle assembly 128, the catheter shaft 110, the balloon interior 146 of the balloon 104, the fluid pump 138, and at or along the inflation conduit 140 to effectively sense and / or monitor internal balloon pressure within the balloon interior 146 of the balloon 104. Alternatively, the one or more pressure sensors 141S may be positioned at any other suitable location along the fluid path of the catheter fluid 132 utilized to selectively inflate the balloon 104.

[0120] The one or more pressure sensors 141S may have any suitable design for sensing and / or monitoring the internal balloon pressure of the catheter fluid 132 held within the balloon interior 146 of the balloon 104 during operation of the catheter system 100. For example, in certain non-exclusive embodiments, the one or more pressure sensors 141S may be selected from the group consisting of a fiber optic sensor, a diaphragm sensor, and a MEMS sensor. Alternatively, the one or more pressure sensors 141S may have another suitable design.

[0121] In addition to being useful for determining the outer diameter 104BD of the balloon 104 as part of the diameter correlation system 147, the sensed internal balloon pressure sensed by one or more pressure sensors 141S of the pressure sensor assembly 141 may also be utilized to address other issues related to the performance, reliability, and safety of the catheter 102, particularly catheters that utilize an energy source 124 to generate a localized plasma that induces high-energy gas bubbles inside the balloon 104. For example, additional issues that may be addressed by the pressure sensor assembly 141 include, but are not limited to, (1) detecting a rupture or breakage of the balloon 104, (2) detecting successful firing of the plasma generator 133, (3) detecting failure of the plasma generator 133, and (4) monitoring the progress of a procedure and the effectiveness of the treatment.

[0122] The contact detector assembly 142 is configured to effectively detect and / or monitor the position of the balloon wall 130 of the balloon 104 relative to the vessel wall 108A of the blood vessel 108 at the treatment site 106. More specifically, in various embodiments of the contact detector assembly 142, the contact detector assembly 142 can be configured to: 1) provide feedback to the user when the balloon wall 130 is in optimal contact with the vessel wall 108A at the treatment site 106 to optimize energy delivery and therapeutic effect; 2) when the balloon 104 is too small for the blood vessel 108 being treated; and 3) detect any condition in which the balloon contact is not optimal for treatment.

[0123] In many embodiments, the catheter system 100 can function through multiple mechanisms. The first mechanism is to pump a nominal 4 atmospheres (atm) (4.053×10) of pressure through the balloon 104. 5The pressures applied to the balloon 104 include static loading of the vessel wall 108A due to hydrostatic pressure applied at a pressure of 100 psi (20 Pa). The static loading and contact with the vessel wall 108A create an optimal path for the transmission of acoustic energy from the plasma-driven energy source 124 to the vascular lesion 106A at the treatment site 106. The static loading of the vessel wall 108A, as well as the coupling efficiency of the acoustic energy, contribute to the effectiveness of the catheter system 100. For optimal operation of the catheter system 100, it is important that the balloon 104 is properly sized.

[0124] The second mechanism involves the coupling of acoustic energy from the local plasma to the vascular lesion 106A. For the effectiveness and performance of this type of catheter system 100, it is essential that the outer diameter 104BD of the balloon 104 be sized to precisely fit the inner diameter 108D of the blood vessel 108 being treated. Ideally, the catheter system 100 and / or contact detector assembly 142 assess the fit of the catheter 102 as it is inserted into the blood vessel 108 and provide feedback to the user regarding the sufficiency of the fit between the fully inflated balloon 104 and the blood vessel 108 being treated.

[0125] A balloon 104 that is properly sized for the blood vessel 108 being treated will clear the blood 305 from the blood vessel 108 when the balloon 104 is fully inflated and the balloon wall 130 is brought into contact with the vessel wall 108A. Alternatively, a balloon 104 that is too small for the blood vessel 108 being treated will not completely clear the blood 305 from the blood vessel 108 when inflated. As a result, a ring of blood 305 remains between the balloon wall 130 and the vessel wall 108A. As described herein, the presence or absence of blood 305 under such conditions can be detected by optical means. The absorption spectra of the blood 305 and the tissue that makes up the vessel wall 108A differ over a wide wavelength range in the visible and near-infrared (IR) spectrum. This concept allows the contact detector assembly 142 to effectively diagnose how much blood 305 is present between the balloon wall 130 and the vessel wall 108A and, therefore, whether optimal contact exists between the balloon wall 130 and the vessel wall 108A.

[0126] As described in detail herein, the primary fluid detected by the contact detector assembly 142 is blood 305. However, it should be understood that the contact detector assembly 142 may be configured and utilized to detect any type of fluid that may be present within the blood vessel 108, such as between the balloon wall 130 and the blood vessel wall 108A. For example, in certain embodiments, there may be a mixture of contrast agent and blood 305 or a mixture of saline and blood 305. Accordingly, one skilled in the art will understand that the contact detector assembly 142 may be configured to detect any fluid or blood-fluid mixture through wavelength selection.

[0127] It should also be understood that the polymer comprising the balloon wall 130 of the balloon 104 is optically transparent over the above range of wavelengths in the visible and near-IR spectrum.

[0128] It should be further understood that the contact detector assembly 142 may have any suitable design for the purpose of effectively detecting whether or not optimal contact exists between the balloon wall 130 and the vessel wall 108 A. Some non-exclusive examples of potential designs and applications for the contact detector assembly 142 are described in detail herein below.

[0129] In many embodiments, the contact detector assembly 142 can include an optical splitting and light detection device that provides a means for probing the space between the balloon wall 130 and the vessel wall 108A using existing optics and hardware for high-energy delivery and plasma generation. For example, in some embodiments, the contact detector assembly 142 uses the energy guide 122A and plasma generator 133 to deliver first light energy at a selected wavelength from the illumination sources 366, 368 to the space between the balloon wall 130 and the vessel wall 108A, after which the distal light receiver 122R collects backscattered light therefrom in the form of second light energy (sometimes referred to as a “return energy beam”) and returns it to the components of the contact detector assembly 142 for analysis to detect blood 305 or other fluids within the probed space. Alternatively, in other embodiments, the desired functions of the contact detector assembly 142 can be performed using separate energy guides and energy directing and collecting devices. In such alternative embodiments, the separate energy guide utilized by the contact detector assembly 142 may be an optical guide, while the original energy guide 122A may be replaced by any suitable type of energy guide, such as electrical, acoustic, pneumatic, mechanical, etc., in some non-exclusive embodiments.

[0130] In most, if not all, embodiments of the catheter system 100 including a contact detector assembly 142 having features of the present invention, if a suboptimal balloon wall 130 relative to the vessel wall 108A condition is detected by the contact detector assembly 142, the therapeutic procedure is prevented or stopped to mitigate the associated risk to the patient 109. In certain embodiments, this may include locking out the energy source 124 through the use of a safety shutdown system 362 (shown in FIG. 3A ), which in some such embodiments may include one or more of a safety interlock 362A (shown in FIG. 3A ) and a shutter 362B (shown in FIG. 3A ) that may be utilized in conjunction with the contact detector assembly 142. This provides the necessary safety interlock and mitigation measures for a potentially dangerous situation in which an undesirable risk to the patient 109 may exist. Furthermore, the system controller 126 may be used to instruct the operator, such as via the GUI 127, to stop treatment and / or remove the catheter 102 from the patient 109 undergoing treatment when such a suboptimal condition is determined to exist. It should be further understood that the safety interlock system 362 may also be used in the initial stages of using the contact detector assembly 142, in which case the energy source 124 may be locked out before the contact detector assembly 142 is utilized to determine whether optimal contact has been established between the balloon wall 130 of the balloon 104 and the vessel wall 108A of the blood vessel 108.

[0131] As with all embodiments shown and described herein, various features may be omitted from the drawings for purposes of clarity and ease of understanding. Additionally, the drawings may include certain features that may be omitted without departing from the spirit and scope of the present invention.

[0132] 2 is a flowchart illustrating a first mode of operation of an embodiment of a catheter system including an embodiment of a vessel wall contact detector assembly. It should be understood that any of the steps listed in the flowchart of FIG. 2 may be modified, deleted, and / or combined in any suitable manner, and / or the order of the steps may be changed, without departing from the intended spirit and scope of the present invention. Also, one or more steps may be added to the sequence of steps specifically shown and described in the flowchart without departing from the intended spirit and scope of the present invention.

[0133] Referring briefly to FIG. 3A, FIG. 3A is a simplified schematic diagram of a portion of an embodiment of a catheter system 300 including an embodiment of a vessel wall contact detector assembly 342 usable within a first mode of operation as described in connection with FIG. 2.

[0134] The design of the catheter system 300 and the contact detector assembly 342 may vary. It should be understood that various components of the catheter system 300 as shown in Figure 1 are not shown in Figure 3A for clarity and ease of illustration. However, it should be understood that the catheter system 300 is expected to include most, if not all, of such components.

[0135] In various embodiments, as illustrated in FIG. 3A , the catheter system includes one or more of a light source 324 (such as, in one non-exclusive embodiment, a pulsed infrared laser light source or another suitable energy source), a pulse generator 360 coupled to the light source 324, a safety shutdown system 362 including a safety interlock 362A and a shutter 362B, a first optical element 364 (such as, in one non-exclusive embodiment, a coupling lens), a light guide 322A (such as, in one non-exclusive embodiment, an optical fiber or another suitable energy guide), a plasma generator 333, a balloon 304 including a balloon wall 330, and a contact detector assembly 342. As further shown in FIG. 3A , the contact detector assembly 342 may include one or more of a first assembly illumination source 366, a first light source driver 366A, a second assembly illumination source 368, a second light source driver 368A, a first redirector 370, a second redirector 372, a first beam splitter 374, a filter 376, a second beam splitter 378, a second optical element 380 (such as an imaging lens in one non-exclusive embodiment), a photodetector 382, ​​an amplifier 384, and control electronics 386, which may include one or more processors or circuits. Alternatively, in other embodiments, the catheter system 300 and / or the contact detector assembly 342 may include more or fewer components than those specifically described above. Further alternatively, in still other embodiments, the various components of the catheter system 300 and / or the contact detector assembly 342 may be arranged in a manner different from that specifically illustrated in FIG. 3A .

[0136] It should be understood that the use of the terms “first assembly illumination source” and “second assembly illumination source” is used merely for convenience and ease of description. Accordingly, it should be further understood that either of the assembly illumination sources 366, 368 may be referred to as a “first assembly illumination source” and / or a “second assembly illumination source.” In addition, it should also be understood that the terms “first optical element” and “second optical element,” “first light source driver” and “second light source driver,” “first redirector” and “second redirector,” and “first beamsplitter” and “second beamsplitter” may also be used interchangeably to identify either of the optical elements 364, 380, either of the light source drivers 366A, 368A, either of the redirectors 370, 372, and either of the beamsplitters 374, 378, respectively.

[0137] FIG. 3A also illustrates that during use of the catheter system 300 and / or the contact detector assembly 342, the balloon wall 330 of the balloon 304 may be placed in (i) good and / or optimal contact with the vascular wall 308A of the blood vessel 308, such as a first state 390A, i.e., a state in which little or no blood 305 is present between the balloon wall 330 and the vascular wall 308A, and / or (ii) poor and / or sub-optimal contact with the vascular wall 308A of the blood vessel 308, such as a second state 390B, i.e., a state in which a relatively thick layer of blood 305 is present between the balloon wall 330 and the vascular wall 308A. In various embodiments, as described herein, the contact detector assembly 342 is uniquely configured to establish whether the balloon wall 330 of the balloon 304 is disposed relative to the vessel wall 308A of the blood vessel 308 in a first state 390A (good or optimal contact between the balloon wall 330 and the vessel wall 308A) or a second state 390B (poor or suboptimal contact between the balloon wall 330 and the vessel wall 308A).

[0138] In this embodiment, the contact detector assembly 342 includes multiple collimated assembly illumination sources 366, 368, each having a specific wavelength. More specifically, this approach involves using two separate assembly illumination sources 366, 368 having different wavelengths, where one assembly illumination source is highly transmitted by the blood 305 and reflected by the vessel wall 308A, and the other assembly illumination source is strongly reflected and / or scattered by the blood 305. Alternatively, the contact detector assembly 342 can include only a single assembly illumination source. Still alternatively, the contact detector assembly 342 can include assembly illumination sources having three or more specific wavelengths.

[0139] In certain embodiments, the assembly illumination sources 366, 368 may be diode lasers, high-intensity LEDs with optics for collimating the emitted beam, or other solid-state light sources. As mentioned above, this embodiment of the present invention uses two different wavelengths, one with a high absorption coefficient for blood 305 and the other with a low absorption coefficient for blood 305. Ideally, these are both at isosbestic points relative to the absorption spectra of O2Hb and deO2Hb, so that the relative oxygenation of blood 305 does not affect the relative absorption or transmission of light energy. Possible wavelengths for the assembly illumination sources 366, 368 are described in more detail below. Note that while a preferred wavelength may be at an isosbestic point relative to the absorption spectra of O2Hb and deO2Hb, it is not necessary for both wavelengths to be at isosbestic points.

[0140] 2, the light source (or other suitable energy source) utilized within the catheter system for the desired therapeutic procedure is disabled in step 201. The light source is disabled so that light energy from the light source is not directed into and through the light guide until optimal contact between the balloon wall and the vessel wall is properly established through the use of a contact detector assembly.

[0141] It should be appreciated that disabling the light source may be accomplished in any suitable manner. For example, in certain embodiments, the light source may be disabled through the use of a safety interlock system, which may employ safety interlocks and / or shutters, through the specific disabling of a pulse generator coupled to the light source, and / or otherwise through cutting off power to the light source.

[0142] 3A , prior to using the catheter system 300 as part of a therapeutic procedure, the control electronics 386 may be configured to send a signal to the safety shutdown system 362 to disable operation of the light source 324. More specifically, in one embodiment, a signal from the control electronics 386 to the safety shutdown system 362 may be used to activate the safety interlock 362A, blocking signals from the pulse generator 360 to the light source 324 and thus substantially ceasing generation of light pulses from the light source 324. Additionally, or alternatively, a signal from the control electronics 386 to the safety shutdown system 362 may be used to activate and close the shutter 362B, thereby blocking light pulses from the light source 324 that would otherwise be directed toward and coupled to the light guide 322A. Such a safety shutdown system 362 substantially prevents use of the catheter system 300 in the event of suboptimal contact between the balloon wall 330 and the vessel wall 308A.

[0143] Returning again to FIG. 2, in step 202, a first assembly illumination source and a second illumination source contained within the contact detector assembly are enabled. In step 203, a first pulse of light energy from a first assembly illumination source is generated and transmitted toward the light guide and through the light guide into the interior of the balloon. The first light energy of the first assembly illumination beam may then be redirected, in one embodiment, by a plasma generator or the like, toward a balloon wall of the balloon and / or a vessel wall of the blood vessel.

[0144] Referring now to FIG. 3B, FIG. 3B is a simplified schematic diagram of a portion of an embodiment of a catheter system 300 including an embodiment of a vessel wall contact detector assembly 342 shown in FIG. 3A, illustrating step 203 in a first mode of operation.

[0145] Specifically, as shown, first light source driver 366A activates first assembly illumination source 366 to generate a first pulse of light energy in the form of first assembly illumination beam 366B, which is directed from first assembly illumination source 366 into light guide 322A. The desired wavelength of first assembly illumination beam 366B can vary. In particular, the wavelength range useful for detecting blood and vessel walls spans the full visible range and the near-infrared. In this approach, the short wavelength side is limited by the transmission limit of optical fibers toward the UV, which for IR fused silica is approximately 250 nm. The long wavelength side is limited by the absorption spectrum of biological materials and the bandgap of solid-state photodetectors, which is 1.1 μm for silicon. The use of more specialized materials and detectors can extend this range. For example, UV fused silica is usable down to 180 nm, and InGaAs photodiodes can detect light up to 1.68 μm. Ultimately, the absorption spectrum of the biological materials involved becomes the limiting factor. As previously mentioned, it is preferable to use a wavelength at the isosbestic point of hemoglobin, but this is not essential for the function of the method. An isosbestic point refers to a specific wavelength at which the total absorbance of a sample does not change during a chemical reaction or physical change in the sample. In this case, it relates to the change from deO2Hb to its oxygenated form, O2Hb. Over the wavelength range of 200-900 nm, there are 11 isosbestic points for deO2Hb and O2Hb: 255, 350, 390, 422, 452, 500, 529, 545, 570, 584, and 805 nm.

[0146] In certain non-exclusive embodiments, first assembly illumination beam 366B can be at a wavelength (e.g., about 550 nm and 600 nm) that is generally strongly scattered and / or reflected upon contact with blood 305. Alternatively, first assembly illumination beam 366B can be at another suitable wavelength.

[0147] First assembly illumination beam 366B is initially directed toward and redirected by first redirector 370 (e.g., a mirror in one non-exclusive embodiment) (in certain implementations, first assembly illumination beam 366B may be redirected approximately 90 degrees). First assembly illumination beam 366B is directed through second redirector 372, such as a dichroic mirror that transmits certain wavelengths of light and redirects other wavelengths of light, before entering first beam splitter 374.

[0148] At least a portion of the first assembly illumination beam 366B is transmitted through the first beam splitter 374, which in certain non-exclusive embodiments may be a non-polarizing variable beam splitter, such as a 50 / 50 R / T. In one embodiment, if the first assembly illumination source 366 is a diode laser with high brightness, a low transmission beam splitter, such as a 90 / 10, may be used, which allows for a much larger return signal to the contact detector assembly 342. A polarizing beam splitter may also be used to polarize the first assembly illumination beam 366B from the first assembly illumination source 366 to obtain 100% transmission.

[0149] The portion of the first assembly illumination beam 366B transmitted through the first beam splitter 374 then passes through a filter 376, such as a short-pass filter in one non-exclusive embodiment. Thus, the illumination and detection system of the contactor assembly 342 is isolated from the high-energy light source 324 using the filter 376. This eliminates back-reflected light during pulsed plasma operation, improving the SNR to the photodetector 382 and allowing the contact detector assembly 342 to operate even when the catheter system 300 is in a treatment mode.

[0150] After passing through filter 376, the remaining portion of first assembly illumination beam 366B then enters second beam splitter 378, which, in certain embodiments, is a dichroic beam splitter that can transmit light at certain wavelengths and redirect light at other wavelengths. In certain embodiments, second beam splitter 378 is configured to pass or transmit light of wavelengths longer than the wavelength detectable by photodetector 382. Such a threshold wavelength may be referred to as a cutoff wavelength. Second beam splitter 378 is further configured to reflect all light having wavelengths shorter than the cutoff wavelength. It should be understood that first assembly illumination beam 366B is at a wavelength such that it is substantially entirely reflected by second beam splitter 378.

[0151] As shown, the remaining portion of first assembly illumination beam 366B is redirected by second beam splitter 378 before passing through first optical element 364 to collimate first assembly illumination beam 366B, and first light energy from this portion of first assembly illumination beam 366B is focused onto proximal guide end 322P of light guide 322A. First light energy from the portion of first assembly illumination beam 366B is guided through light guide 322A, emitted at distal guide end 322D of light guide 322A, and then incident on plasma generator 333. In certain embodiments, plasma generator 333 is provided in the form of a backstop-type structure having an angled surface 333F, which can redirect the first light energy toward balloon wall 330 of balloon 304 and / or toward vessel wall 308A of blood vessel 308 at treatment site 306. Thus, angled surface 333F of plasma generator 333 functions like a single-facet mirror. Due to the low numerical aperture of light guide 322A when immersed in catheter fluid 132 (shown in FIG. 1), the beam spot of first assembly illumination beam 366B at the surface of angled surface 333F is narrow, resulting in a highly focused spot on balloon wall 330 and nearby tissue (e.g., vessel wall 308A of blood vessel 308). As explained in more detail herein below, this intense spot is scattered by blood 305 or vessel wall 308A and redirected by angled surface 322F back toward guide distal end 322D of light guide 322A, where it is collected within the numerical aperture of guide distal end 322D of light guide 322A.

[0152] As shown in FIG. 3B, the first light energy from a portion of the first assembly illumination beam 366B is generally reflected upon contact with the blood 305, whether the balloon 390 is in a good contact state 304A or a poor contact state 390B.

[0153] Returning again to FIG. 2, in step 204, at least a portion of the first light energy from the first assembly illumination source is reflected and / or backscattered from the blood and directed back through the light guide and then analyzed by the contact detector assembly.

[0154] Referring now to FIG. 3C, FIG. 3C is a simplified schematic diagram of a portion of an embodiment of a catheter system 300 including an embodiment of a vessel wall contact detector assembly 342 shown in FIG. 3A, illustrating step 204 in a first mode of operation.

[0155] Specifically, as shown, a portion of the first light energy from the first assembly illumination source 366 incident on the balloon wall 330 is reflected and / or backscattered from the blood 305 and received by the distal light receiver 322R as second light energy and / or first return energy beam 366R, which couples the second light energy and / or first return energy beam 366R into the guide distal end 322D of the light guide 322A. In certain embodiments, the angled surface 333F of the plasma generator 333 can collect the second light energy reflected and / or backscattered from the blood 305 and redirect the second light energy back into the guide distal end 322D of the light guide 322A. Thus, the angled surface 333F of the plasma generator 333 can function like a single-facet mirror and function as at least a portion of the distal light receiver 322R.

[0156] The second optical energy and / or first return energy beam 366R then emits from the guide proximal end 322P, from where it is directed through a first optical element 364, which collimates the first return energy beam 366R. The collimated first return energy beam 366R is then directed to a second beam splitter 378, such as a dichroic beam splitter.

[0157] Due to the specific wavelength of first return energy beam 366R, at least a portion of first return energy beam 366R is redirected by second beam splitter 378 and then directed through filter 376 to enter first beam splitter 374. In other words, first beam splitter 374 is disposed in the optical path of first return energy beam 366R reflected from second beam splitter 378. This forms a bidirectional system that probes treatment site 306 through light guide 322A and detects conditions therein by second optical energy returned in the form of first return energy beam 366R. The two paths provide a path for transmitting first assembly illumination beam 366B (shown in FIG. 3B ) to proximal guide end 322P of light guide 322A and a path for collecting the second optical energy of first return energy beam 366R returning from distal guide end 322D.

[0158] At least a portion of the first returning energy beam 366R is then redirected by the first beam splitter 374 and passes through the second optical element 380 onto the photodetector 382. The second optical element 380 focuses the collimated first returning energy beam 366R and forms an image of the end face of the light guide 322A onto the photodetector 382, ​​thereby coupling out light emitted from the proximal guide end 322P of the light guide 322A. In certain non-exclusive alternative embodiments, the photodetector 382 can be a photodiode, an area sensor such as a CCD or CMOS camera, or a spectrophotometer. In an appropriate configuration, the sequence of optical elements 364, 380 can form a high-resolution image of the end face of the light guide 322A on the image sensor.

[0159] The photodetector 382 then generates a signal based on the intensity of the light at the particular wavelength. In some embodiments, the photodetector 382 generates a signal based on the second light energy or first return energy beam 366R reflected and / or backscattered from the blood 305 received by the distal light receiver 322R at or near the guide distal end 322D of the light guide 322A and collected by the photodetector 382.

[0160] The signal from the photodetector 382 is directed to an amplifier 384, which amplifies the signal from the photodetector 382 and then transmits it to control electronics 386 for processing and analysis. Alternatively, in other embodiments, the contact detector assembly 342 may be designed without an amplifier 384. In such alternative embodiments, the signal from the photodetector 382 may be transmitted to the control electronics 386 for processing and analysis. In either embodiment, the signal from the photodetector 382 may be used by the control electronics 386 to determine the contact condition between the balloon wall 330 and the vessel wall 308A (shown in FIG. 3A ).

[0161] In some embodiments, the control electronics 386 may be included as part of the system controller 126 (shown in FIG. 1 ). Alternatively, the control electronics 386 may be provided separately from the system controller 126 and in electrical communication with the system controller 126.

[0162] 2, in step 205, a first pulse of light energy from a second assembly light source is generated in the form of a second assembly illumination beam and transmitted through the light guide into the interior of the balloon. The first light energy of the second assembly illumination beam may then be redirected, in one embodiment, by a plasma generator or the like, toward a balloon wall of the balloon and / or a vessel wall of the blood vessel.

[0163] Referring now to FIG. 3D, FIG. 3D is a simplified schematic diagram of a portion of an embodiment of a catheter system 300 including an embodiment of a vessel wall contact detector assembly 342 shown in FIG. 3A, illustrating step 205 in a first mode of operation.

[0164] Specifically, as shown, second light source driver 368A activates second assembly illumination source 368 to generate a first pulse of light energy in the form of second assembly illumination beam 368B, which is directed from second assembly illumination source 368 into light guide 322A. The desired wavelength of second assembly illumination beam 368B can vary. In particular, the wavelength range useful for blood and vessel wall detection spans the full visible range and the near-infrared. In this approach, the short wavelength side is limited by the transmission limit of optical fibers toward the UV, which for IR fused silica is approximately 250 nm. The long wavelength side is limited by the absorption spectrum of biological materials and the bandgap of solid-state photodetectors, which is 1.1 μm for silicon. The use of more specialized materials and detectors can extend this range. For example, UV fused silica is usable down to 180 nm, and InGaAs photodiodes can detect light up to 1.68 μm. Ultimately, the absorption spectrum of the biological material involved becomes the limiting factor. As previously mentioned, it is preferable to use a wavelength at the isosbestic point of hemoglobin, but this is not essential for the function of the method. An isosbestic point refers to a specific wavelength at which the total absorbance of a sample does not change during a chemical reaction or physical change in the sample. In this case, it relates to the change from deO2Hb to its oxygenated form, O2Hb. Over the wavelength range of 200-900 nm, there are 11 isosbestic points for deO2Hb and O2Hb: 255, 350, 390, 422, 452, 500, 529, 545, 570, 584, and 805 nm.

[0165] In certain non-exclusive embodiments, the second assembly illumination beam 368B may be at a wavelength (e.g., approximately 640 nm and 750 nm) that passes through and / or is transmitted by the blood 305 and is then generally reflected upon contact with the blood vessel wall 308A. Alternatively, the second assembly illumination beam 368B may be at another suitable wavelength.

[0166] The second assembly illumination beam 368B is first directed toward and redirected by a second redirector 372 (e.g., a dichroic mirror that transmits certain wavelengths of light and redirects other wavelengths of light) (in certain embodiments, the second assembly illumination beam 368B may be redirected approximately 90 degrees). The second assembly illumination beam 368B is then directed toward and enters a first beam splitter 374.

[0167] At least a portion of the second assembly illumination beam 368B is transmitted through the first beam splitter 374, which in certain non-exclusive embodiments may be a non-polarizing variable beam splitter, such as a 50 / 50 R / T. In one embodiment, if the second assembly illumination source 368 is a diode laser with high brightness, a low transmission beam splitter, such as a 90 / 10, may be used, which allows for a much larger return signal to the contact detector assembly 342. A polarizing beam splitter may also be used to polarize the second assembly illumination beam 368B from the second assembly illumination source 368 to obtain 100% transmission.

[0168] The portion of second assembly illumination beam 368B transmitted by first beam splitter 374 then passes through filter 376 and enters second beam splitter 378, which, in certain embodiments, is a dichroic beam splitter that can transmit light at certain wavelengths and redirect light at other wavelengths. In certain embodiments, second beam splitter 378 is configured to pass or transmit light of wavelengths longer than the wavelength detectable by photodetector 382. Such a threshold wavelength is referred to as the cutoff wavelength. Second beam splitter 378 is further configured to reflect all light having wavelengths shorter than the cutoff wavelength. It should be understood that second assembly illumination beam 368B is of a wavelength such that it is substantially entirely reflected by second beam splitter 378.

[0169] As shown, the remaining portion of second assembly illumination beam 368B is redirected by second beam splitter 378 before passing through first optical element 364 to collimate second assembly illumination beam 368B, and first light energy from the portion of second assembly illumination beam 368B is focused onto proximal guide end 322P of light guide 322A. First light energy from the portion of second assembly illumination beam 368B is guided through light guide 322A, emitted at distal guide end 322D of light guide 322A, and then incident on plasma generator 333. In certain embodiments, angled surface 333F of plasma generator 333 redirects the first light energy of second assembly illumination beam 368B toward balloon wall 330 of balloon 304 and / or toward vessel wall 308A of blood vessel 308 at treatment site 306. Thus, angled surface 333F of plasma generator 333 functions like a single-facet mirror. Due to the low numerical aperture of light guide 322A when immersed in catheter fluid 132 (shown in FIG. 1), the beam spot of second assembly illumination beam 368B at the surface of angled surface 333F is narrow, resulting in a highly focused spot on balloon wall 330 and nearby tissue (e.g., vessel wall 308A of blood vessel 308). As explained in more detail herein below, this intense spot penetrates blood 305, is scattered by vessel wall 308A, and is redirected by angled surface 333F of plasma generator 333 back toward guide distal end 322D of light guide 322A and collected within the numerical aperture of guide distal end 322D of light guide 322A.

[0170] As shown in FIG. 3D, first light energy from a portion of second assembly illumination beam 368B passes through blood 305 and is then generally reflected upon contact with blood vessel wall 308A, whether balloon 390 is in good contact condition 304A or poor contact condition 390B.

[0171] Returning again to FIG. 2, in step 206, at least a portion of the first light energy from the second assembly illumination source is reflected and / or backscattered from the vessel wall and guided back through the light guide and then analyzed by the contact detector assembly.

[0172] Referring now to FIG. 3E, FIG. 3E is a simplified schematic diagram of a portion of an embodiment of a catheter system 300 including an embodiment of a vessel wall contact detector assembly 342 shown in FIG. 3A, illustrating step 206 in a first mode of operation.

[0173] Specifically, as shown, a portion of the first light energy from second assembly illumination source 368 reflects and / or backscatters from vessel wall 308A and returns as second light energy and / or second return energy beam 368R to be received by distal light receiver 322R, which couples the second light energy and / or second return energy beam 368R into guide distal end 322D of light guide 322A. In certain embodiments, angled surface 333F of plasma generator 333 can collect the second light energy reflected and / or backscattered from vessel wall 308A and redirect the second light energy back to guide distal end 322D of light guide 322A. Thus, angled surface 333F of plasma generator 333 can function like a single-facet mirror and function as at least a portion of distal light receiver 322R.

[0174] The second optical energy and / or second return energy beam 368R then emits from the guide proximal end 322P, from where it is directed through a first optical element 364, which collimates the second return energy beam 368R. The collimated second return energy beam 368R is then directed to a second beam splitter 378, such as a dichroic beam splitter.

[0175] Due to the specific wavelength of second return energy beam 368R, at least a portion of second return energy beam 368R is redirected by second beam splitter 378 and then directed through filter 376 and incident on first beam splitter 374. In other words, first beam splitter 374 is positioned in the optical path of second return energy beam 368R reflected from second beam splitter 378. This forms a bidirectional system that probes treatment site 306 through light guide 322A and detects conditions thereat by the second optical energy returned in the form of second return energy beam 368R. Two paths provide a path for transmitting second assembly illumination beam 368B to proximal guide end 322P of light guide 322A and a path for collecting the second optical energy of second return energy beam 322R returning from distal guide end 368D.

[0176] At least a portion of the second returning energy beam 368R is then redirected by the first beam splitter 374 and passes through the second optical element 380 onto the photodetector 382. The second optical element 380 focuses the collimated second returning energy beam 368R to form an image of the end face of the light guide 322A onto the photodetector 382, ​​thereby coupling out light emitted from the proximal guide end 322P of the light guide 322A.

[0177] The photodetector 382 then generates a signal based on the intensity of the light at the particular wavelength. In some embodiments, the photodetector 382 generates a signal based on a second light energy or second return energy beam 368R reflected and / or backscattered from the vessel wall 308A that is received by a distal light receiver 322R at or near the guide distal end 322D of the light guide 322A and collected by the photodetector 382.

[0178] The signal from the photodetector 382 is directed to an amplifier 384, which amplifies the signal from the photodetector 382 and then transmits it to control electronics 386 for processing and analysis. Alternatively, in other embodiments, the contact detector assembly 342 may be designed without an amplifier 384. In such alternative embodiments, the signal from the photodetector 382 may be transmitted to the control electronics 386 for processing and analysis. In either embodiment, the signal from the photodetector 382 may be used by the control electronics 386 to determine the contact condition between the balloon wall 330 and the vessel wall 308A (shown in FIG. 3A ).

[0179] Returning again to FIG. 2, in step 207, the signals generated during the analysis of the first and second returning energy beams are compared to determine the quality of contact that exists between the balloon wall and the vessel wall.

[0180] In particular, as described in this mode of operation, the contact detector assembly 342 can pulse or modulate the two assembly illumination sources 366, 368 in time to allow the photodetector 382 and / or control electronics 386 to distinguish between them through temporal analysis or gating. More specifically, the control electronics 386 analyzes the ratio of the return signals. This method provides a means of automatically calibrating for variability in light source intensity, coupling coefficient, transmission coefficient, and geometry and optical properties of the analyzed area.

[0181] Thus, in a specific embodiment, the method used herein is configured to pulse the two assembly illumination sources 366, 368 closely spaced in time. The control electronics 386 sends short pulses at a first wavelength to the first light source driver 366A for the first assembly illumination source 366 and then reads the amplified signal from the photodetector. This results in absorption for the first wavelength. The control electronics 386 then sends short pulses at a second wavelength to the second light source driver 368A for the second assembly illumination source 368 and then reads the amplified signal from the photodetector. This results in absorption for the second wavelength. The pulses have very short durations, on the order of a few microseconds to tens of microseconds, and are closely spaced in time. As the pulse shapes approach rectangular shapes, their FWHMs become shorter. This allows the contact detector assembly 342 to operate continuously at very high sampling rates. A variety of modulation and pulse shaping schemes are available.

[0182] However, it should be understood that there are other ways to achieve this spectral multiplexing. For example, in one non-exclusive alternative embodiment, the contact detector assembly 342 can include two separate photodetectors, each with a narrow bandpass filter (BPF). In one embodiment, the beam focused by the imaging lens can be split onto two separate photodetectors using a dichroic mirror. The dichroic mirror thus creates a symmetric multiplexer-demultiplexer (MDM). Both assembly illumination sources 366, 368 are then operated in continuous wave (CW) mode, allowing for continuous scanning. The photodetector 382 can be a spectrograph or multiple single detectors that split the beam using a dispersive element such as a grating or prism. The illumination and detection sections can be inverted across a beam splitter, with the detector and imaging lens on a transmissive surface and the probe illumination on a reflective surface.

[0183] As described, in this embodiment, two different wavelength light sources, λ1 and λ2, are used. The λ1 light from the first assembly illumination source 366 is attenuated when blood 305 is present in the space between the balloon wall 330 and the vessel wall 308A. The λ2 light from the second assembly illumination source 368 passes through the blood 305 and is scattered by the vessel wall 308A.

[0184] When blood 305 is present, as in the second (bad or suboptimal) condition 390B, λ1 is attenuated and very little light returns to the photodetector 382. The signal S(λ1) is very small. However, λ2 passes through the blood 305 and is scattered back to the photodetector 382. The signal S(λ2) is larger. Some loss occurs due to scattering by blood cells. Conversely, when little or no blood 305 is present, as in the first (good or optimal) condition 390A, both wavelengths are scattered back to the photodetector 382 and S(λ1) is equal to S(λ2).

[0185] The ratio of the two signals provides an indication of the presence or absence of blood 305 and the degree of thickness of that layer. Because both assembly illumination beams 366B, 368B are transmitted to guide distal end 322D along the same optical path, and both detected lights are also collected and transmitted along the same path including collection optics, this ratiometric approach cancels out all of these factors, allowing the system to self-calibrate.

[0186] Alternatively, as described below in connection with Figures 6 and 7A-7D, it is possible to practice the invention using a single wavelength light source. For example, using only wavelength λ1, which has high penetration through blood. As the thickness of the blood layer increases, the attenuation of light returning from the vessel wall through that layer increases. As less returning light is collected and the layer thickness increases, S(λ1) varies proportionally. This approach requires calibration to null out the effects of coupling and transmission through each portion of the optical path. This can serve as a go-no-go technique to indicate the presence of blood, which can cause a gap between the balloon wall and the vessel wall.

[0187] In other embodiments, the assembly illumination source(s) can include multiple narrow bands of wavelengths. The photodetector 382 can have multiple individual photodetectors and NBP filters, as described above, or can be a spectrometer. Detection schemes involve more complex calculations based on multiple wavelengths, accounting for transmission losses, coupling in the plasma generator 333, scattering in the blood, and many other physical phenomena that can affect the accuracy of the photodetector 382. In the broadest embodiment, the light source is broadband, such as a high-intensity white LED, and the photodetector 382 is a spectrometer. A supercontinuum white light laser (WLL) could work for this application, and many other light sources are possible. This approach can obtain the spectrum of the returned light and then separately resolve it into blood and tissue spectra using techniques such as eigendecomposition. This provides a highly accurate indication of the presence of blood or other fluid in the space between the balloon wall 330 and the vessel wall 308A. The two-wavelength approach is a limiting case.

[0188] In step 208, if the comparison performed in step 207 determines that there is poor or suboptimal contact between the balloon wall and the vessel wall, the current usage of the balloon is modified. In certain non-exclusive circumstances, modifying the usage of the balloon may include inflating the balloon to a different level (adjusting the internal balloon pressure), moving the balloon to a modified position relative to the treatment site, and / or removing the catheter and using a catheter with a balloon that is more appropriately sized for the treatment procedure.

[0189] In step 209, if the comparison made in step 207 determines that good or optimal contact exists between the balloon wall and the vessel wall, the light source (or other suitable energy source) is enabled and used within the catheter system for the desired therapeutic procedure.

[0190] Referring now to FIG. 3F, FIG. 3F is a simplified schematic diagram of a portion of an embodiment of a catheter system 300 including an embodiment of a vessel wall contact detector assembly 342 shown in FIG. 3A, illustrating step 209 in a first mode of operation.

[0191] In particular, as shown, light source 324 is enabled and safety interlock system 362, including interlock 362A and shutter 362B, no longer inhibits the generation and / or direction of light energy from light source 324. Pulse generator 360 is configured to trigger light source 324 such that a pulse of light energy is generated by light source 324. The light energy from light source 324, in the form of light source beam 324A, is directed toward second beam splitter 378, such as a dichroic beam splitter in one embodiment. In other words, second beam splitter 378 is disposed in the optical path of light source beam 324A between light source 324 and proximal guide end 322P of light guide 322A.

[0192] In certain embodiments, second beam splitter 378 is configured to pass or transmit light of wavelengths longer than the detectable wavelength for photodetector 382, ​​such that light source beam 324A is directed toward proximal guide end 322P of light guide 322A. Such threshold wavelength is referred to as the cutoff wavelength. Second beam splitter 378 is further configured to reflect all light having wavelengths shorter than the cutoff wavelength.

[0193] As shown in this embodiment, the first optical element 364 is disposed between the second beam splitter 378 and the light guide 322A and is configured to collimate the light source beam 324A and focus the light source beam 324A onto the guide base end 322P of the light guide 322A, thereby coupling the light source beam 324A into the light guide 322A.

[0194] In various embodiments, source beam 324A has a wavelength, such as in the infrared spectrum, and after transmitting through second beam splitter 378, the optical energy of source beam 324A passes through first optical element 364 and is focused onto proximal guide end 322P of light guide 322A. The optical energy of source beam 324A is then guided along and / or through light guide 322A and emitted at distal guide end 322D into balloon interior 146 (shown in FIG. 1 ) of balloon 304. The optical energy of source beam 324A is redirected to impinge on angled surface 333F of plasma generator 333, activating angled surface 333F to generate a localized plasma within catheter fluid 132 (shown in FIG. 1 ) in balloon interior 146.

[0195] In one embodiment, light guide 322A is a small diameter multimode optical fiber used to direct light transmitted from light source 324 and / or assembly illumination sources 366, 368, and plasma generator 333 includes a beveled backstop to direct light toward vessel wall 308A. The beveled backstop (sloped surface 333F) of light guide 333A and plasma generator 322 serves a dual purpose: to deliver high-energy light for plasma generation (as shown in FIG. 3F) and low-energy light for blood and tissue discrimination (as shown in FIGS. 3B and 3D). The beveled backstop (inclined surface 333F) of the plasma generator 333 is also used in conjunction with and / or as part of the terminal optical receiver 322R to collect light reflected and / or backscattered from the illuminated area and couple that light back into the light guide 322A for transmission back to the contact detector assembly 342 for detection and analysis (as shown in Figures 3C and 3E).

[0196] In another embodiment, the contact detector assembly 342 can include a separate illumination beam guide 892 (illustrated in FIG. 8) in the form of an optical fiber used for blood and tissue discrimination, in addition to the optical guide 322A in the form of an optical fiber used for high-energy delivery and plasma generation. In one embodiment, in conjunction with the illumination beam guide 892, an energy directing element, such as a mirror, can be attached to the distal end of the illumination beam guide 892 to direct a first optical energy from the assembly illumination beam 366B (illustrated in FIG. 3B), 368B (illustrated in FIG. 3D) toward the balloon wall 330 and / or the vessel wall 308A, and redirect the returning energy beam back to and through the illumination beam guide 892 for subsequent analysis by the contact detector assembly 342. Alternatively, the end face at the distal end of the illumination beam guide 892 can also be angled to have a side-emitting feature, directing the optical energy from the side and collecting scattered light within the numerical aperture of the illumination beam guide 892. 3F shows the state of the system when optimal contact is achieved between the balloon wall 330 and the vessel wall 308A. The control electronics 386 determines that conditions are optimal, turns off the assembly illumination sources 366, 368, opens the shutter 362B, and activates the light source 324, such as an infrared laser, to generate a plasma and produce therapeutic acoustic energy.

[0197] Figure 4 is a flowchart illustrating a second mode of operation of an embodiment of a catheter system including the embodiment of the vessel wall contact detector assembly of Figure 3 A. It should be understood that any of the steps listed in the flowchart of Figure 4 may be modified, deleted, and / or combined in any suitable manner, and / or the order of the steps may be changed, without departing from the intended spirit and scope of the present invention. Also, one or more steps may be added to the sequence of steps specifically shown and described in the flowchart without departing from the intended spirit and scope of the present invention.

[0198] The light source (or other suitable energy source) utilized within the catheter system for the desired therapeutic procedure is disabled in step 401. The light source is disabled so that light energy from the light source is not directed into and through the light guide until optimal contact between the balloon wall and the vessel wall is properly established through the use of a contact detector assembly.

[0199] It should be appreciated that disabling the light source may be accomplished in any suitable manner. For example, in certain embodiments, the light source may be disabled through the use of a safety interlock system, which may employ safety interlocks and / or shutters, through the specific disabling of a pulse generator coupled to the light source, and / or otherwise through cutting off power to the light source.

[0200] In step 402, a first assembly illumination source and a second illumination source contained within the contact detector assembly are enabled. In step 403, a first pulse of light energy from a first assembly illumination source is generated in the form of a first assembly illumination beam, and a second pulse of light energy from a second assembly illumination source is generated in the form of a second assembly illumination beam. As described herein, in a second mode of operation, such as shown in FIG. 4, the first assembly illumination beam and the second assembly illumination beam are generated substantially simultaneously and then combined and transmitted together into a light guide. The light guide then directs the combined beam into the interior of the balloon, from which the light energy of the combined beam is redirected toward a balloon wall of the balloon and / or a vessel wall of the blood vessel.

[0201] Referring now to FIG. 5A, FIG. 5A is a simplified schematic diagram of a portion of an embodiment of a catheter system 300 including an embodiment of the vessel wall contact detector assembly 342 of FIG. 3A, showing step 403 in a second mode of operation.

[0202] Specifically, as shown, first light source driver 366A activates first assembly illumination source 366 to generate a first pulse of light energy in the form of first assembly illumination beam 366B. Substantially simultaneously, second light source driver 368A activates second assembly illumination source 368 to generate a first pulse of light energy in the form of second assembly illumination beam 368B.

[0203] The desired wavelengths of the first assembly illumination beam 366B and the second assembly illumination beam 368B can vary. In particular, the wavelength range useful for detecting blood and vessel walls spans the entire visible range and into the near-infrared. In this approach, the short wavelength side is limited by the transmission limit of optical fibers toward the UV, approximately 250 nm for IR fused silica. The long wavelength side is limited by the absorption spectrum of biological materials and the band gap of solid-state photodetectors, which is 1.1 μm for silicon. The use of more specialized materials and detectors can extend this range. For example, UV fused silica can be used down to 180 nm, and InGaAs photodiodes can detect light up to 1.68 μm. Ultimately, the absorption spectrum of the biological material involved becomes the limiting factor. As mentioned above, using a wavelength at the isosbestic point of hemoglobin is preferred, but this is not essential for the functionality of the method. An isosbestic point refers to a specific wavelength at which the total absorbance of a sample does not change during a chemical reaction or physical change in the sample. In this case, it concerns the conversion of deO2Hb to its oxygenated form, O2Hb. Over the wavelength range of 200-900 nm, deO2Hb and O2Hb have 11 isosbestic points: 255, 350, 390, 422, 452, 500, 529, 545, 570, 584, and 805 nm.

[0204] In some non-exclusive embodiments, the first assembly illumination beam 366B can be at a wavelength (e.g., about 550 nm and 600 nm) that is generally strongly reflected upon contact with the blood 305. Additionally, in certain non-exclusive embodiments, the second assembly illumination beam 368B can be at a wavelength (e.g., about 640 nm and 750 nm) that is generally transmitted through the blood 305 and then strongly reflected upon contact with the vessel wall 308A of the blood vessel 308. Alternatively, the first assembly illumination beam 366B and / or the second assembly illumination beam 368B can be at another suitable wavelength.

[0205] The first assembly illumination beam 366B is initially directed toward and redirected by a first redirector 370 (e.g., a mirror in one non-exclusive embodiment) (in certain implementations, the first assembly illumination beam 366B may be redirected approximately 90 degrees). The first assembly illumination beam 366B is then directed toward a second redirector 372, such as a dichroic mirror that transmits certain wavelengths of light and redirects other wavelengths of light. At substantially the same time, the second assembly illumination beam 368B is initially directed toward the second redirector 372.

[0206] Due to the different wavelengths of the first and second assembly illumination beams 366B, 368B, and the particular design of the second redirector 372, the first assembly illumination beam 366B is transmitted through the second redirector 372, and the second assembly illumination beam 368B is redirected by the second redirector 372. Because the assembly illumination beams 366B, 368B are generated and directed substantially simultaneously, the second redirector 372 functions to combine the assembly illumination beams 366B, 368B into a combined illumination beam 566C, which is then directed towards and incident on the first beam splitter 374.

[0207] At least a portion of the combined illumination beam 566C is transmitted through a first beam splitter 374, which may have any suitable design, as described above. The portion of the combined illumination beam 566C transmitted through the first beam splitter 374 then passes through a filter 376 and is incident on a second beam splitter 378, which, in certain embodiments, is a dichroic beam splitter that can transmit light at certain wavelengths and redirect light at other wavelengths. In certain embodiments, the second beam splitter 378 is configured to pass or transmit light of wavelengths longer than the wavelength detectable by the photodetector 382. Such a threshold wavelength is referred to as the cutoff wavelength. The second beam splitter 378 is further configured to reflect all light having a wavelength shorter than the cutoff wavelength. It should be understood that the combined illumination beam 566C is at a wavelength such that it is substantially entirely reflected by the second beam splitter 378.

[0208] As shown, the remaining portion of combined illumination beam 566C is redirected by second beam splitter 378 before passing through first optical element 364 to collimate combined illumination beam 566C, and first light energy from the portion of combined illumination beam 566C is focused onto proximal guide end 322P of light guide 322A. The first light energy from the portion of combined illumination beam 566C is guided through light guide 322A, emitted at distal guide end 322D of light guide 322A, and then incident on plasma generator 333. In certain embodiments, angled surface 333F of plasma generator 333 redirects the first light energy of combined illumination beam 566C toward balloon wall 330 of balloon 304 and / or toward vessel wall 308A of blood vessel 308 at treatment site 306. Thus, angled surface 333F of plasma generator 333 functions like a single-faceted mirror. Due to the low numerical aperture of light guide 322A when immersed in catheter fluid 132 (shown in FIG. 1), the beam spot of combined illumination beam 566C on the surface of angled surface 333F is narrow. Due to the different wavelengths contained within combined illumination beam 566C, the redirected combined illumination beam 566C forms a highly focused spot on nearby tissue, such as balloon wall 330 and vessel wall 308A of blood vessel 308.

[0209] As described in more detail herein below, one intense spot from the portion of combined illumination beam 566C that originates from first assembly illumination beam 366B at a first wavelength is scattered by blood 305, and one intense spot from the portion of combined illumination beam 566C that originates from second assembly illumination beam 368B at a second wavelength is scattered by blood 305. The portion of combined illumination beam 566C that is scattered back from blood 305 and vessel wall 308A is redirected by angled surface 333F back toward guide end 322D of light guide 322A and collected within the numerical aperture of guide end 322D of light guide 322A.

[0210] As shown in FIG. 5A, the first light energy from the portion of the combined illumination beam 566C derived from the first assembly illumination beam 366B is generally reflected when it contacts the blood 305, whether the balloon 304 is in a good contact state 304A or a poor contact state 390B, and the first light energy from the portion of the combined illumination beam 566C derived from the second assembly illumination beam 368B passes through the blood 305 and then is generally reflected when it contacts the blood vessel wall 308A, whether the balloon 390 is in a good contact state 390A or a poor contact state 390B.

[0211] Thus, as illustrated, the contact detector assembly 342 includes two collimated assembly illumination sources 366, 368, each with a specific wavelength. These light sources can be diode lasers, high-intensity LEDs with optics for collimating the emitted beam, or other solid-state light sources. This embodiment of the invention uses two different wavelengths, one with a high absorption coefficient for blood and the other with a low absorption coefficient. Ideally, these are both isosbestic points relative to the absorption spectra of O2Hb and deO2Hb, so that the relative oxygenation of blood does not affect the relative absorption or transmission of light. In this embodiment, the assembly illumination beams 366B, 368B from the two assembly illumination sources 366, 368 are combined into a single combined illumination beam 566C using a second redirector 372, such as a dichroic mirror. The single dual-wavelength combined illumination beam 566C is reflected by a high-energy second beam splitter 378 and coupled to the proximal end 322P of the light guide 322A. Light is emitted from guide end 322D of light guide 322A and directed by angled surface 333F of plasma generator 333 towards balloon wall 330 and / or vessel wall 308A.

[0212] 4, in step 404, a portion of the first light energy from the combined illumination beam is reflected and / or backscattered from the blood, and another portion of the first light energy from the combined illumination beam is reflected and / or backscattered from the blood vessel wall, and these portions of light energy are then guided back through the light guide and analyzed by the contact detector assembly.

[0213] Referring now to FIG. 5B, FIG. 5B is a simplified schematic diagram of a portion of an embodiment of a catheter system 300 including an embodiment of the vessel wall contact detector assembly 342 of FIG. 3A, showing step 404 in a second mode of operation.

[0214] Specifically, as shown, a portion of the first light energy of combined illumination beam 566C (shown in FIG. 5A ) from first assembly illumination source 366 that is incident on balloon wall 330 is reflected and / or backscattered from blood 305, and a portion of the first light energy of combined illumination beam 566C from second assembly illumination source 368 that is incident on balloon wall 330 is reflected and / or backscattered from blood vessel wall 330A. A portion of such first light energy from combined illumination beam 566C is reflected and / or backscattered as second light energy and / or combined return energy beam 566R and received by distal light receiver 322R, which couples second light energy and / or combined return energy beam 566R into guide distal end 322D of light guide 322A. In certain embodiments, the angled surface 333F of the plasma generator 333 can collect secondary light energy reflected and / or backscattered from the blood 305 and vessel wall 308A and redirect the secondary light energy back toward the guide distal end 322D of the light guide 322A. Thus, the angled surface 333F of the plasma generator 333 can function like a single-facet mirror and function as at least a portion of the distal light receiver 322R.

[0215] The second optical energy and / or combined return energy beam 566R then emits from the guide proximal end 322P, from where it is directed through a first optical element 364, which collimates the combined return energy beam 566R. The collimated combined return energy beam 566R is then directed to a second beam splitter 378, such as a dichroic beam splitter.

[0216] Due to the specific wavelengths contained within combined return energy beam 566R, at least a portion of combined return energy beam 566R is redirected by second beam splitter 378 and then directed through filter 376 and incident on first beam splitter 374. In other words, first beam splitter 374 is positioned in the optical path of combined return energy beam 566R reflected from second beam splitter 378. This forms a bidirectional system that probes treatment site 306 through light guide 322A and detects conditions thereat by the second optical energy returned in the form of combined return energy beam 566R. Two paths provide a path for transmitting combined illumination beam 566C to proximal guide end 322P of light guide 322A and a path for collecting the second optical energy of combined return energy beam 566R returning from distal guide end 322D.

[0217] At least a portion of the coupled return energy beam 566R is then redirected by the first beam splitter 374 and passes through the second optical element 380 onto the photodetector 382. The second optical element 380 focuses the collimated coupled return energy beam 566R to form an image of the end face of the light guide 322A onto the photodetector 382, ​​thereby coupling out light emitted from the proximal guide end 322P of the light guide 322A. In some non-exclusive alternative embodiments, the photodetector 382 can be a photodiode, an area sensor such as a CCD or CMOS camera, or a spectrophotometer. In an appropriate configuration, the sequence of optical elements 364, 380 can generate a high-resolution image of the end face of the light guide 322A on the image sensor.

[0218] Photodetector 382 then generates signals based on the intensity of light at each of the two particular wavelengths. In some embodiments, photodetector 382 generates (i) a first signal based on the second light energy of combined return energy beam 566R reflected and / or backscattered from blood 305 received by distal light receiver 322R at or near guide distal end 322D of light guide 322A and collected by photodetector 382, ​​and (ii) a second signal based on the second light energy of combined return energy beam 566R reflected and / or backscattered from blood vessel wall 308A received by distal light receiver 322R at or near guide distal end 322D of light guide 322A and collected by photodetector 382. In other words, the photodetector 382 generates (i) a first signal based on the second optical energy of the combined return energy beam 566R at a first wavelength, and (ii) a second signal based on the second optical energy of the combined return energy beam 566R at a second wavelength.

[0219] The signal from the photodetector 382 is directed to an amplifier 384, which amplifies the signal from the photodetector 382 and transmits it to control electronics 386 for processing and analysis. Alternatively, in other embodiments, the contact detector assembly 342 may be designed without an amplifier 384. In such alternative embodiments, the signal from the photodetector 382 may be transmitted to the control electronics 386 for processing and analysis. In either embodiment, the signal from the photodetector 382 may be used by the control electronics 386 to determine the contact condition between the balloon wall 330 and the vessel wall 308A.

[0220] When the two assembly illumination sources 366, 368 are combined into one beam, both wavelengths are present at a single photodetector 382. Different wavelengths must be distinguished in a multispectral approach to obtain separate spectral signals for ratiometric analysis. The method used in this embodiment can separate the two return light sources using a dichroic beam splitter or other optical means, such as a grating or spectrometer. The photodetector 382 then generates separate first and second signals representing the absorption of the first and second wavelengths, respectively.

[0221] As mentioned above, like the previous embodiment, this embodiment uses two different wavelength light sources, λ1 and λ2. The λ1 light from the first assembly illumination source 366 is attenuated when blood 305 is present in the space between the balloon wall 330 and the vessel wall 308A. The λ2 light from the second assembly illumination source 368 passes through the blood 305 and is scattered by the vessel wall 308A.

[0222] When blood 305 is present, as in the second (bad or suboptimal) condition 390B, λ1 is attenuated and very little light returns to photodetector 382. The signal S(λ1) is very small. However, λ2 passes through the blood 305 and is scattered back to photodetector 382. The signal S(λ2) is larger. Some loss occurs due to scattering by blood cells. Conversely, when little or no blood 305 is present, as in the first (good or optimal) condition, both wavelengths are scattered back to photodetector 382 and S(λ1) is equal to S(λ2).

[0223] The ratio of the two signals provides an indication of the presence or absence of blood 305 and the degree of thickness of that layer. Because both assembly illumination beams 366B, 368B are transmitted to guide distal end 322D along the same optical path, and both detected lights are collected and transmitted along the same path including collection optics, this ratiometric approach cancels out all of these factors, allowing the system to self-calibrate.

[0224] 4, in step 408, if the analysis performed in step 404 determines that there is poor or suboptimal contact between the balloon wall and the vessel wall, then the current usage of the balloon is modified. In certain non-exclusive circumstances, modifying the usage of the balloon may include inflating the balloon to a different level (adjusting the internal balloon pressure), moving the balloon to a modified position relative to the treatment site, and / or removing the catheter and using a catheter with a balloon that is more appropriately sized for the treatment procedure.

[0225] In step 409, if the analysis performed in step 404 determines that good or optimal contact exists between the balloon wall and the vessel wall, the light source (or other suitable energy source) is enabled and used within the catheter system for the desired therapeutic procedure.

[0226] Referring now to FIG. 5C, FIG. 5C is a simplified schematic diagram of a portion of an embodiment of a catheter system 300 including an embodiment of a vessel wall contact detector assembly 342 shown in FIG. 3A, illustrating step 409 in a second mode of operation.

[0227] In particular, as shown, light source 324 is enabled and safety interlock system 362, including interlock 362A and shutter 362B, no longer inhibits the generation and / or direction of light energy from light source 324. Pulse generator 360 is configured to trigger light source 324 such that a pulse of light energy is generated by light source 324. The light energy from light source 324, in the form of light source beam 324A, is directed toward second beam splitter 378, such as a dichroic beam splitter in one embodiment. In other words, second beam splitter 378 is disposed in the optical path of light source beam 324A between light source 324 and proximal guide end 322P of light guide 322A.

[0228] In certain embodiments, second beam splitter 378 is configured to pass or transmit light of wavelengths longer than the detectable wavelength for photodetector 382, ​​such that light source beam 324A is directed toward proximal guide end 322P of light guide 322A. Such threshold wavelength is referred to as the cutoff wavelength. Second beam splitter 378 is further configured to reflect all light having wavelengths shorter than the cutoff wavelength.

[0229] As shown in this embodiment, the first optical element 364 is disposed between the second beam splitter 378 and the light guide 322A and is configured to collimate the light source beam 324A and focus the light source beam 324A onto the guide base end 322P of the light guide 322A, thereby coupling the light source beam 324A into the light guide 322A.

[0230] In various embodiments, source beam 324A has a wavelength, such as in the infrared spectrum, and after transmitting through second beam splitter 378, the optical energy of source beam 324A passes through first optical element 364 and is focused onto proximal guide end 322P of light guide 322A. The optical energy of source beam 324A is then guided along and / or through light guide 322A and emitted at distal guide end 322D into balloon interior 146 (shown in FIG. 1 ) of balloon 304. The optical energy of source beam 324A is redirected to impinge on angled surface 333F of plasma generator 333, activating angled surface 333F to generate a localized plasma within catheter fluid 132 (shown in FIG. 1 ) in balloon interior 146.

[0231] In one embodiment, the light guide 322A is a small-diameter, multimode optical fiber used to direct light transmitted from the light source 324 and / or assembly illumination sources 366, 368, and the plasma generator 333 includes a beveled backstop to direct light toward the vessel wall 308A. The beveled backstop (beveled surface 333F) of the light guide 322A and plasma generator 333 serves a dual purpose: to deliver high-energy light for plasma generation (as shown in FIG. 5C) and low-energy light for blood and tissue discrimination (as shown in FIG. 5A). The beveled backstop (beveled surface 333F) of the plasma generator 333 is also used in conjunction with and / or as part of the distal optical receiver 322R to collect reflected and / or backscattered light from the illuminated area and couple that light back into the light guide 322A for transmission back to the contact detector assembly 342 for detection and analysis (as shown in FIG. 5B).

[0232] Figure 6 is a flowchart illustrating an operational mode of another embodiment of a catheter system including another embodiment of a vessel wall contact detector assembly. It should be understood that any of the steps listed in the flowchart of Figure 6 may be modified, deleted, and / or combined in any suitable manner, and / or the order of the steps may be changed, without departing from the intended spirit and scope of the present invention. Also, one or more steps may be added to the sequence of steps specifically shown and described in the flowchart without departing from the intended spirit and scope of the present invention.

[0233] Referring to FIG. 7A, FIG. 7A is a simplified schematic diagram of a portion of an embodiment of a catheter system 700 including an embodiment of a vessel wall contact detector assembly 742 usable within the operational mode as described in connection with FIG. 6.

[0234] The design of the catheter system 700 is substantially similar to the embodiments shown and described herein above. It should be understood that various components of the catheter system 700, such as those shown in Figure 1, are not shown in Figure 7A for clarity and ease of illustration. However, it should be understood that the catheter system 700 is expected to include most, if not all, of such components.

[0235] As shown in FIG. 7A, the catheter system 700 also includes one or more of a light source 724 (such as a pulsed infrared laser light source, in one non-exclusive embodiment, or another suitable energy source), a pulse generator 760 coupled to the light source 724, a safety shutdown system 762 including a safety interlock 762A and a shutter 762B, a first optical element 764 (such as a coupling lens, in one non-exclusive embodiment), a light guide 722A (such as an optical fiber, in one non-exclusive embodiment, or another suitable energy guide), a plasma generator 733, a balloon 704 including a balloon wall 730, and a contact detector assembly 742.

[0236] However, the contact detector assembly 742 has a slightly different design than the previous embodiment. For example, as further shown in FIG. 7A , the contact detector assembly 742 may also include one or more of a first beam splitter 774, a filter 776, a second beam splitter 778, a second optical element 780 (such as an imaging lens in one non-exclusive embodiment), a photodetector 782, an amplifier 784, and control electronics 786, which may include one or more processors or circuits. However, in this embodiment, the contact detector assembly 742 includes only one assembly illumination source 766, one light source driver 766A, and one redirector 770. Alternatively, in other embodiments, the catheter system 700 and / or the contact detector assembly 742 may include more or fewer components than those specifically described above. Further alternatively, in still other embodiments, the various components of the catheter system 700 and / or the contact detector assembly 742 may be arranged in a manner different from that specifically illustrated in FIG. 7A .

[0237] FIG. 7A also illustrates that during use of the catheter system 700 and / or contact detector assembly 742, the balloon wall 730 of the balloon 704 may be in (i) good and / or optimal contact with the vascular wall 708A of the blood vessel 708, such as a first state 790A, i.e., a state in which little or no blood 705 is present between the balloon wall 730 and the vascular wall 708A, and / or (ii) poor and / or sub-optimal contact with the vascular wall 708A of the blood vessel 708, such as a second state 790B, i.e., a state in which a relatively thick layer of blood 705 is disposed between the balloon wall 730 and the vascular wall 708A. In various embodiments, the contact detector assembly 742 is similarly configured to establish whether the balloon wall 730 of the balloon 704 is disposed relative to the vessel wall 708A of the blood vessel 708 in a first state 790A (good or optimal contact between the balloon wall 730 and the vessel wall 708A) or a second state 790B (poor or suboptimal contact between the balloon wall 730 and the vessel wall 708A).

[0238] In this embodiment, the contact detector assembly 742 includes only one assembly illumination source 766 at a single specific wavelength. Specifically, in this embodiment, the simplest detection method is to illuminate the blood 705 with narrowband light having a center wavelength that passes through the blood 705 with high transmittance but is reflected from the vessel wall 708A. Ideally, this is an isosbestic point relative to the spectrum of oxyhemoglobin (OHb) and deoxyhemoglobin (deOHb). This reduces the effect of blood oxygenation on the signal. As shown, and as described in more detail herein below, the assembly illumination source 766 is coupled to the proximal guide end 722P of the light guide 722A, and light emitted from the distal guide end 722D is directed toward the vessel wall 708A. If blood 705 is present in the space between the balloon wall 730 and the vessel wall 708A, most of the light is absorbed, and only a small amount of light is scattered back and collected by the distal guide end 722D of the light guide 722A and returned to the photodetector 782. In the absence of blood 705, the light is transmitted to the vessel wall 708A and scattered back to the photodetector 782. Using this method, the system will detect a strong return signal indicating good contact between the balloon wall 730 and the vessel wall 708A, while a small or absent signal will indicate poor contact. This is an absolute detection method that relies on multiple factors related to intensity, coupling, and transmittance, and will likely require some means of calibration.

[0239] 6, the light source (or other suitable energy source) utilized within the catheter system for the desired therapeutic procedure is disabled in step 601. The light source is disabled so that light energy from the light source is not directed into and through the light guide until optimal contact between the balloon wall and the vessel wall is properly established through the use of a contact detector assembly.

[0240] It should be appreciated that disabling the light source may be accomplished in any suitable manner. For example, in certain embodiments, the light source may be disabled through the use of a safety interlock system, which may employ safety interlocks and / or shutters, through the specific disabling of a pulse generator coupled to the light source, and / or otherwise through cutting off power to the light source.

[0241] In step 602, an assembly illumination source contained within the contact detector assembly is enabled. In step 603, a first pulse of light energy from an assembly illumination source is generated in the form of an assembly illumination beam and transmitted toward the light guide and through the light guide into the interior of the balloon. The first light energy of the assembly illumination beam may then be redirected, in one embodiment, by a plasma generator or the like, toward a balloon wall of the balloon and / or a vessel wall of the blood vessel.

[0242] Referring now to FIG. 7B, FIG. 7B is a simplified schematic diagram of a portion of an embodiment of a catheter system 700 including an embodiment of a vessel wall contact detector assembly 742 shown in FIG. 7A, illustrating step 603 in an operational mode.

[0243] Specifically, as shown, light source driver 766A activates assembly illumination source 766 to generate a first pulse of light energy in the form of assembly illumination beam 766B, which is directed from assembly illumination source 766 into light guide 722A. The desired wavelength of assembly illumination beam 766B can vary. In particular, the wavelength range useful for blood and vessel wall detection spans the full visible range and the near-infrared. In this approach, the short wavelength side is limited by the transmission limit of optical fibers toward the UV, which for IR fused silica is approximately 250 nm. The long wavelength side is limited by the absorption spectrum of biological materials and the bandgap of solid-state photodetectors, which is 1.1 μm for silicon. The use of more specialized materials and detectors can extend this range. For example, UV fused silica is usable down to 180 nm, and InGaAs photodiodes can detect light up to 1.68 μm. Ultimately, the absorption spectrum of the biological materials involved is the limiting factor. As previously mentioned, it is preferable to use a wavelength at the isosbestic point of hemoglobin, although this is not essential for the functionality of the method. An isosbestic point refers to a specific wavelength at which the total absorbance of a sample does not change during a chemical reaction or physical change in the sample. In this case, it relates to the change from deO2Hb to its oxygenated form, O2Hb. Over the wavelength range of 200-900 nm, there are 11 isosbestic points for deO2Hb and O2Hb: 255, 350, 390, 422, 452, 500, 529, 545, 570, 584, and 805 nm.

[0244] In certain non-exclusive embodiments, assembly illumination beam 766B may be at a wavelength (e.g., about 640 nm, 750 nm, etc.) that passes through and / or is transmitted by blood 705 and is then generally reflected upon contact with blood vessel wall 708A. Alternatively, assembly illumination beam 766B may be at another suitable wavelength.

[0245] The assembly illumination beam 766B is first directed towards and redirected by a redirector 770 (e.g., a mirror in one non-exclusive embodiment) (in a particular implementation, the assembly illumination beam 766B is redirected approximately 90 degrees). The assembly illumination beam 766B is then directed towards and enters a first beam splitter 774.

[0246] At least a portion of the assembly illumination beam 766B is transmitted through a first beam splitter 774, which in certain non-exclusive embodiments may be a non-polarizing variable beam splitter, such as a 50 / 50 R / T. In one embodiment, if the assembly illumination source 766 is a diode laser with high brightness, a low transmission beam splitter, such as a 90 / 10, may be used, allowing for a much larger return signal to the contact detector assembly 742. A polarizing beam splitter may also be used to polarize the assembly illumination beam 766B from the assembly illumination source 766 to obtain 100% transmission.

[0247] The portion of the assembly illumination beam 766B transmitted through the first beam splitter 774 then passes through a filter 776, such as a short-pass filter in one non-exclusive embodiment. Thus, the illumination and detection system of the contact detector assembly 742 is isolated from the high-energy light source 724 using the filter 776. This eliminates back-reflected light during pulsed plasma operation, improving the SNR to the photodetector 782 and allowing the contact detector assembly 742 to operate even when the catheter system 700 is in a treatment mode.

[0248] After passing through filter 776, a portion of assembly illumination beam 766B then enters second beam splitter 778, which, in certain embodiments, is a dichroic beam splitter that can transmit light at certain wavelengths and redirect light at other wavelengths. In certain embodiments, second beam splitter 778 is configured to pass or transmit light of wavelengths longer than the wavelength detectable by photodetector 782. Such a threshold wavelength is referred to as the cutoff wavelength. Second beam splitter 778 is further configured to reflect all light having wavelengths shorter than the cutoff wavelength. It should be understood that assembly illumination beam 766B is at a wavelength such that it is substantially entirely reflected by second beam splitter 778.

[0249] As shown, the remaining portion of the assembly illumination beam 766B is redirected by the second beam splitter 778 before passing through the first optical element 764 to collimate the assembly illumination beam 766B, and first light energy from this portion of the assembly illumination beam 766B is focused onto the proximal guide end 722P of the light guide 722A. The first light energy from the portion of the assembly illumination beam 766B is guided through the light guide 722A, emitted at the distal guide end 722D of the light guide 722A, and then incident on the plasma generator 733. In certain embodiments, the plasma generator 733 is provided in the form of a backstop-type structure having an inclined surface 733F, which can redirect the first light energy toward the balloon wall 730 of the balloon 704 and / or toward the vessel wall 708A of the blood vessel 708 at the treatment site 706. The inclined surface 733F of the plasma generator 733 thus functions like a single-faceted mirror. Due to the low numerical aperture of light guide 722A when immersed in catheter fluid 132 (shown in FIG. 1 ), the beam spot of assembly illumination beam 766B at the surface of angled surface 733F is narrow, resulting in a very focused spot on balloon wall 730 and nearby tissue (e.g., vessel wall 708A of blood vessel 708). As explained in more detail herein below, this intense spot is scattered by blood 705 and / or vessel wall 708A and redirected by angled surface 722F back toward guide end 733D of light guide 722A, where it is collected within the numerical aperture of guide end 722D of light guide 722A.

[0250] As shown in FIG. 7B, the first light energy from a portion of the assembly illumination beam 766B is generally reflected upon contact with the vessel wall 708A of the blood vessel 708, whether the balloon 790 is in a good contact state 790A or a poor contact state 704B.

[0251] Returning again to FIG. 6, in step 604, at least a portion of the first light energy from the assembly illumination source is reflected and / or backscattered from the vessel wall and guided back through the light guide and then analyzed by the contact detector assembly.

[0252] Referring now to FIG. 7C, FIG. 7C is a simplified schematic diagram of an embodiment of a catheter system 700 including an embodiment of a vessel wall contact detector assembly 742 shown in FIG. 7A, illustrating step 604 in an operational mode.

[0253] Specifically, as shown, a portion of the first light energy from the assembly illumination source 766 incident on the balloon wall 730 is reflected and / or backscattered from the vessel wall 708A and received by the distal light receiver 722R as a second light energy and / or return energy beam 766R, which couples the second light energy and / or return energy beam 766R into the guiding distal end 722D of the light guide 722A. In certain embodiments, the angled surface 733F of the plasma generator 733 can collect the second light energy reflected and / or backscattered from the vessel wall 708A and redirect the second light energy back to the guiding distal end 722D of the light guide 722A. Thus, the angled surface 733F of the plasma generator 733 can function like a single-faceted mirror and function as at least a portion of the distal light receiver 722R.

[0254] The second optical energy and / or return energy beam 766R then emits from the guide proximal end 722P, from which it is directed through a first optical element 764, which collimates the return energy beam 766R. The collimated return energy beam 766R is then directed to a second beam splitter 778, such as a dichroic beam splitter.

[0255] Due to the particular wavelength of the return energy beam 766R, at least a portion of the return energy beam 766R is redirected by the second beam splitter 778 and then directed through the filter 776 and incident on the first beam splitter 774. In other words, the first beam splitter 774 is positioned in the optical path of the return energy beam 766R reflected from the second beam splitter 778. This forms a bidirectional system that probes the treatment site 706 through the light guide 722A and detects conditions thereat by the second optical energy returned in the form of the return energy beam 766R. The two paths provide a path for transmitting the assembly illumination beam 766B (shown in FIG. 7B ) into the proximal guide end 722P of the light guide 722A and a path for collecting the second optical energy of the return energy beam 722R returning from the distal guide end 766D.

[0256] At least a portion of the returning energy beam 766R is then redirected by the first beam splitter 774 and passes through the second optical element 780 onto the photodetector 782. The second optical element 780 focuses the collimated returning energy beam 766R and forms an image of the end face of the light guide 722A onto the photodetector 782, thereby coupling out light emitted from the proximal guide end 722P of the light guide 722A. In some non-exclusive alternative embodiments, the photodetector 782 can be a photodiode, an area sensor such as a CCD or CMOS camera, or a spectrophotometer. In an appropriate configuration, the sequence of optical elements 764, 780 can generate a high-resolution image of the end face of the light guide 722A on the image sensor.

[0257] The photodetector 782 then generates a signal based on the intensity of the light at the particular wavelength. In some embodiments, the photodetector 782 generates a signal based on a second light energy or return energy beam 766R reflected and / or backscattered from the vessel wall 708A that is received by a distal light receiver 722R at or near the guide distal end 722D of the light guide 722A and collected by the photodetector 782.

[0258] The signal from the photodetector 782 is directed to an amplifier 784, which amplifies the signal from the photodetector 782 and then transmits it to control electronics 786 for processing and analysis. Alternatively, in other embodiments, the contact detector assembly 742 may be designed without an amplifier 784. In such alternative embodiments, the signal from the photodetector 782 may be transmitted to the control electronics 786 for processing and analysis. In either embodiment, the signal from the photodetector 782 may be used by the control electronics 786 to determine the contact condition between the balloon wall 730 and the vessel wall 708A.

[0259] 6, in step 608, if the analysis performed in step 604 determines that there is poor or suboptimal contact between the balloon wall and the vessel wall, then the current usage of the balloon is modified. In certain non-exclusive circumstances, modifying the usage of the balloon may include inflating the balloon to a different level (adjusting the internal balloon pressure), moving the balloon to a modified position relative to the treatment site, and / or removing the catheter and utilizing a catheter with a balloon that is more appropriately sized for the treatment procedure.

[0260] In step 609, if the analysis performed in step 604 determines that good or optimal contact exists between the balloon wall and the vessel wall, the light source (or other suitable energy source) is enabled and used within the catheter system for the desired therapeutic procedure.

[0261] Referring now to FIG. 7D, FIG. 7D is a simplified schematic diagram of a portion of an embodiment of a catheter system 700 including an embodiment of a vessel wall contact detector assembly 742 shown in FIG. 7A, illustrating step 609 in an operational mode.

[0262] In particular, as shown, light source 724 is enabled and safety interlock system 762, including interlock 762A and shutter 762B, no longer inhibits the generation and / or direction of light energy from light source 724. Pulse generator 760 is configured to trigger light source 724 such that a pulse of light energy is generated by light source 724. The light energy from light source 724, in the form of light source beam 724A, is directed toward second beam splitter 778, such as a dichroic beam splitter in one embodiment. In other words, second beam splitter 778 is disposed in the optical path of light source beam 724A between light source 724 and proximal guide end 722P of light guide 722A.

[0263] In certain embodiments, the second beam splitter 778 is configured to pass or transmit light of wavelengths longer than the detectable wavelength for the photodetector 782, such that the light source beam 724A is directed toward the proximal guide end 722P of the light guide 722A. Such a threshold wavelength is referred to as the cutoff wavelength. The second beam splitter 778 is further configured to reflect all light having wavelengths shorter than the cutoff wavelength.

[0264] As shown in this embodiment, the first optical element 764 is disposed between the second beam splitter 778 and the light guide 722A and is configured to collimate the light source beam 724A and focus the light source beam 724A onto the guide base end 722P of the light guide 722A, thereby coupling the light source beam 724A into the light guide 722A.

[0265] In various embodiments, source beam 724A has a wavelength, such as in the infrared spectrum, and after transmitting through second beam splitter 778, the optical energy of source beam 724A passes through first optical element 764 and is focused onto proximal guide end 722P of light guide 722A. The optical energy of source beam 724A is then guided along and / or through light guide 722A and emitted at distal guide end 722D into balloon interior 146 (shown in FIG. 1 ) of balloon 704. The optical energy of source beam 724A is redirected to impinge on angled surface 733F of plasma generator 733, activating angled surface 733F to generate a localized plasma within catheter fluid 132 (shown in FIG. 1 ) in balloon interior 146.

[0266] In one embodiment, the light guide 722A is a small-diameter multimode optical fiber used to direct light transmitted from the light source 724 and / or assembly illumination source 766, and the plasma generator 733 includes a beveled backstop to direct light toward the vessel wall 708A. The beveled backstop (beveled surface 733F) of the light guide 722A and plasma generator 733 serves a dual purpose: to deliver high-energy light for plasma generation (as shown in FIG. 7D) and low-energy light for blood and tissue discrimination (as shown in FIG. 7B). The beveled backstop (beveled surface 733F) of the plasma generator 733 is also used in conjunction with and / or as part of the distal optical receiver 722R to collect reflected and / or back-scattered light from the illuminated area and couple that light back into the light guide 722A for return to the contact detector assembly 742 for detection and analysis (as shown in FIG. 7C).

[0267] In summary, all of the contact detector assembly embodiments presented above use a light guide and backstop to illuminate the space between the balloon wall and the vessel wall and collect light from this space for detection and analysis. This may be the preferred method for implementing a contact detector assembly in an existing hardware design because it 1) uses the catheter's existing configuration and does not increase its size or cross-sectional profile; 2) can be incorporated into existing multiplexer, connector, and laser designs; and 3) provides a detector for each emitter (or a series of emitters located at a single longitudinal position relative to the balloon's length). These are all important factors for successful implementation. The first factor is important because the catheter's dimensions are critical to its maneuverability and lesion-crossing performance. The third factor is more important in effectively detecting the blood layer, which indicates a gap or poor contact. The blood layer will be uneven around the annular region. If only one detector is present on one side of the balloon, that side may be compressed to make intimate contact while a large gap exists on the other side. The balloon may be too small for the vessel, but the detector will indicate to the user that it is within acceptable limits. This is true along the entire length of the balloon. Having one detector on one side of the balloon may result in many false positives.

[0268] Despite these advantages, one possible variation that could work around the presented embodiment is to use separate illumination beam guides to guide the assembly illumination beams to the balloon wall and the vessel wall. One such embodiment is shown in FIG. 8. This embodiment has a mirror attached to the distal end of the guide to direct the assembly illumination beam(s) from the assembly illumination source(s) toward the vessel wall and then collect the backscattered light for detection. An example of this is a microprism or bevel on the end face of the illumination beam guide itself, forming a side-emitting fiber through total internal reflection (TIR). This optical assembly is inserted through the catheter shaft and has a distal tip attached along the balloon's interior lumen. Multiple optical assemblies can be arranged in this manner along the balloon's length. However, each one would require a separate ferrule position in the connector to connect to the system. This is difficult with existing multiplexer systems and disposable connectors with a fixed number of ferrules. However, it is possible to implement it as an additional ferrule interposed between the initial ferrules for the high energy fiber, or as a second row of ferrules.

[0269] In this alternative approach, the entire coupling optics and contact detector assembly can be fixed relative to the illumination beam guide, eliminating the need for a multiplexer for channel switching. This can be a fixed system independent of the high-energy multiplexing system. This is outlined in FIG. 8. Multiple fibers can be connected to this system, and their proximal end faces can be fused together to form a single end cap for coupling the assembly illumination source to this subsystem. Without loss of generality, this can be implemented as a separate system coupled to one or more fibers running separately from the high-energy plasma-forming fiber. This can be implemented using a separate optical connector or integrated into the high-energy connector.

[0270] It should be further appreciated that this configuration of the contact detector assembly can be adapted to detect whether or not optimal contact exists between the balloon wall and the vessel wall in all types of catheter systems and catheters in which the contact detector assembly is incorporated.

[0271] Figure 8 is a simplified schematic diagram of yet another embodiment of a catheter system 800 including yet another embodiment of a vessel wall contact detector assembly 842. The design of the catheter system 800 is substantially similar to the embodiments shown and described herein above. It should be understood that various components of the catheter system 800, such as those shown in Figure 1, are not shown in Figure 8 for clarity and ease of illustration. However, it should be understood that the catheter system 800 is expected to include most, if not all, of such components.

[0272] As shown in FIG. 8, the catheter system 800 also includes one or more of a light source 824 (such as a pulsed infrared laser light source in one non-exclusive embodiment, or another suitable energy source), a pulse generator 860 coupled to the light source 824, a safety shutdown system 862 including a safety interlock 862A and a shutter 862B, a first optical element 864 (such as a coupling lens in one non-exclusive embodiment), a light guide 822A (such as an optical fiber in one non-exclusive embodiment, or another suitable energy guide), a plasma generator 833, a balloon 804 including a balloon wall 830, and a contact detector assembly 842.

[0273] 8, contact detector assembly 842 can include one or more of a first assembly illumination source 866, a first light source driver 866A, a second assembly illumination source 868, a second light source driver 868A, a first redirector 870, a second redirector 872, a beam splitter 874, a filter 876, a third redirector 894, a second optical element 896 (such as a coupling lens, in one non-exclusive embodiment), a third optical element 880 (such as an imaging lens, in one non-exclusive embodiment), a photodetector 882, an amplifier 884, and control electronics 886, which can include one or more processors or circuits. It should be understood that contact detector assembly 842 can operate in a substantially similar manner in a first mode of operation (as shown and described in connection with FIGS. 2 and 3A-3F) and / or a second mode of operation (as shown and described in connection with FIGS. 4 and 5A-5C). Alternatively, the contact detector assembly 842 may be designed with only a single assembly illumination source that operates in a manner substantially similar to the mode of operation shown and described in connection with FIGS. 6 and 7A-7D.

[0274] However, in this embodiment, assembly illumination beams 866B, 868B from assembly illumination sources 866, 868 are directed through a separate illumination beam guide 892 rather than through the light guide 822A used for the source beam from light source 824. In this embodiment, for simplicity, the second beam splitter is replaced with a third redirector 894 because source beam 824A is not directed through the third redirector 894 and therefore there is no reason to utilize a dichroic beam splitter that reflects certain wavelengths of light and transmits others.

[0275] In particular, as shown, assembly illumination beams 866B, 868B are first directed toward first redirector 870 and / or second redirector 872, and then directed toward and incident on first beam splitter 874. At least a portion of assembly illumination beams 866B, 868B are transmitted through first beam splitter 874 and pass through filter 876 before being directed toward and incident on third redirector 894.

[0276] The remaining portion of assembly illumination beams 866B, 868B is redirected by a third redirector 894, such as a mirror, and then passes through a second optical element 896, which collimates assembly illumination beams 866B, 868B so that assembly illumination beams 866B, 868B are focused onto proximal guide end 892P of illumination beam guide 892. Assembly illumination beams 866B, 868B are guided through illumination beam guide 892 and emitted at distal guide end 892D of illumination beam guide 892.

[0277] Assembly illumination beams 866B, 868B are then redirected by an energy directing element 898, such as a mirror, attached to guide distal end 892D of illumination beam guide 892, directing assembly illumination beams 866B, 868B toward balloon wall 830 and / or vessel wall 808A. Energy directing element 898 may be further configured to redirect return energy beams 866R, 868R reflected and / or backscattered from blood 805 and / or vessel wall 808A back into and through illumination beam guide 892 for subsequent analysis by contact detector assembly 842. Alternatively, the end face at guide distal end 892D of illumination beam guide 892 may also be angled to form a side-emitting feature that directs light energy out the side and similarly collects scattered light within its numerical aperture.

[0278] The returning energy beams 866R, 868R emitted from the proximal guide end 892P of the illumination beam guide 892 may then be directed through a second optical element 896, redirected by a third redirector 894, and subsequently redirected by the first beam splitter 874. The remaining portions of the returning energy beams 866R, 868R are then directed through a third optical element 880 to a photodetector 882. The photodetector 882 then generates a signal based on the intensity of light at the particular wavelengths in each of the returning energy beams 866R, 868R. The signal from the photodetector 882 is directed to an amplifier 884, which amplifies the signal from the photodetector 882 and transmits it to control electronics 886 for processing and analysis.

[0279] After good contact between balloon wall 830 and vessel wall 808A is determined, light source 824 is enabled and safety interlock system 862, including interlock 862A and shutter 862B, no longer inhibits the generation and / or direction of light energy from light source 824. Pulse generator 860 is configured to trigger light source 824 such that a pulse of light energy is generated by light source 824. The light energy from light source 824 is directed in the form of light source beam 824A towards first optical element 864, which is configured to collimate and focus light source beam 824A onto proximal guide end 822P of light guide 822A, thereby coupling light source beam 824A into light guide 822A.

[0280] The light energy of source beam 824A is then guided along and / or through light guide 822A and emitted at guide distal end 822D into balloon interior 146 (shown in FIG. 1 ) of balloon 804. The light energy of source beam 824A is redirected to impinge on angled surface 833F of plasma generator 833, activating angled surface 833F to generate a localized plasma within catheter fluid 132 (shown in FIG. 1 ) in balloon interior 146.

[0281] Thus, as described above, in various embodiments, the contact detector assembly of the present invention is uniquely configured to: 1) detect when the balloon walls are in optimal contact with the vessel wall at the treatment site to optimize energy delivery and therapeutic effect; 2) identify conditions when the balloon is too small for the vessel being treated and provide feedback to the user; and 3) detect any conditions where balloon contact is less than optimal for treatment.

[0282] However, in addition to the various embodiments detailed hereinabove, alternative approaches can be utilized. For example, more advanced approaches use multiple wavelengths for spectroscopic techniques. The assembly illumination source can be a broad-spectrum light source, such as a high-intensity white LED. In this case, the photodetector is a spectrometer. An example of this is a linear CCD array combined with a grating to disperse the signal. Other spectral separation methods can be used, such as a fixed filter array or a linear variable filter. In this approach, the returned light can be analyzed to extract the spectral characteristics of blood and tissue, which can then be used to determine the relative amounts of blood and tissue in the beam path through space. Eigendecomposition methods such as Principal Component Analysis (PCA) or template correlation can be used for this purpose, although other methods can also be used.

[0283] Other factors should also be considered when designing a suitable catheter system and / or contact detector assembly incorporating the features of the present invention. Such additional factors include, but are not limited to:

[0284] 1) The treatment site is most commonly an artery, so the catheter is exposed only to arterial blood, not venous blood. Because arterial blood is oxygenated, the predominant species is O2Hb. Therefore, the photodetector can operate using wavelengths that are not isosbestic. In this case, a much simpler illumination source, such as an RGB diode trio, can be used. For example, the TCW-RGBS-400R is a fully integrated, three-laser diode module with wavelengths of 450, 520, and 638 nm. In other words, in such an implementation, the integrated multi-wavelength illumination source typically requires only a single illumination assembly for the contact detector assembly.

[0285] 2) Small laser diode modules such as this one can be directly integrated into the multiplexer optical platen. This can be directly integrated into the plasma flash detector module. The photodetector in the plasma flash detector can serve a dual purpose and be the photodetector for the vessel wall contact detector assembly. This allows for significant simplification and miniaturization, making it a practical implementation.

[0286] 3) Another possible workaround is optical coherence tomography (OCT), which can be performed over a single optical fiber, but is very difficult to address with current catheter and multiplexer designs.

[0287] 9 is a simplified schematic diagram of an embodiment of a diameter correlation system 947 having features of the present invention, the diameter correlation system 947 incorporating inputs from and / or outputs to a pressure sensor assembly 941, a balloon compliance chart 955, a balloon diameter determination system 957, a contact detector assembly 942, a vessel diameter determination system 958, and a vessel diameter mapping system 959. In various embodiments, the diameter correlation system 947 is incorporated, at least in part, within the system controller 126 (shown in FIG. 1 ) and is uniquely configured to ensure that the outer diameter 104BD (shown in FIG. 1 ) of the balloon 104 (shown in FIG. 1 ) and the inner diameter 108D (shown in FIG. 1 ) of the blood vessel 108 (shown in FIG. 1 ) are properly correlated for most effective lithotripsy therapy and / or drug delivery at the treatment site 106 (shown in FIG. 1 ).

[0288] As shown, the use and operation of the diameter correlation system 947 involves a multi-step process by which the diameter correlation system 947 can effectively ensure that the outer diameter 104BD of the balloon 104 and the inner diameter 108D of the blood vessel 108 are properly correlated for the most effective lithotripsy therapy and / or drug delivery at the treatment site 106.

[0289] For example, within the balloon diameter determination system 957, a pressure sensor assembly 941 may be used to sense and / or monitor the internal balloon pressure within the balloon interior 146 (shown in FIG. 1 ) of the balloon 104. Thus, the pressure sensor assembly 941 may provide data and / or information regarding the internal balloon pressure to the system controller 126. The system controller 126 may then utilize that data and / or information regarding the internal balloon pressure in conjunction with a balloon compliance chart 955 configured to plot the outer diameter 104BD of the balloon 104 against the internal balloon pressure for a variety of different balloons, with respect to style, size, design, material, etc. Thus, in this manner, the balloon diameter determination system 957 may determine the outer diameter 104BD of the balloon 104 when the catheter system 100 (shown in FIG. 1 ) is utilized to perform a therapeutic procedure at the treatment site 106. In certain embodiments, the relationship between the outer diameter 104BD of the balloon 104 and the internal balloon pressure may be displayed on the GUI 127 (shown in FIG. 1 ) for use by an operator.

[0290] The vessel diameter determination system 958 can then be used to determine the inner diameter 108D of the blood vessel 108 in which the catheter system 100 is being used. In particular, the contact detector assembly 942 can be used in the manner described above to determine when good contact exists between the balloon wall 130 (shown in FIG. 1 ) of the balloon 104 and the vessel wall 108A of the blood vessel 108. Data and / or information regarding the outer diameter 104BD of the balloon 104, as determined through use of the balloon diameter determination system 957, can then be used in conjunction with data and / or information from the contact detector assembly 942 regarding when good contact exists between the balloon wall 130 and the vessel wall 108A to determine the inner diameter 108D of the blood vessel 108. In other words, when good contact exists between the balloon wall 130 of the balloon 104 and the vessel wall 108A of the blood vessel 108, the inner diameter 108D of the blood vessel 108 is equal to the outer diameter 104BD of the balloon 104. Thus, the vessel diameter determination system 958 can determine the inner diameter 108D of the blood vessel 108 at the particular location within the blood vessel 108 where the catheter system is currently being used.

[0291] Additionally, the vessel diameter mapping system 959 can be used to effectively map the inner diameter 108D of the blood vessel 108 at various locations along the region length 106L (shown in FIG. 1 ) of the treatment region 106. More specifically, the vessel diameter determination system 958 can be used in the manner described above to determine the inner diameter 108D of the blood vessel 108 at multiple locations along the region length 106L of the treatment region 106. In many embodiments, the determination of the inner diameter 108D of the blood vessel 108 may be performed at evenly spaced locations along the site length 106L of the treatment site 106, for example, every 0.1 mm, 0.2 mm, 0.5 mm, 0.8 mm, 1.0 mm, 1.5 mm, 2.0 mm, 2.5 mm, 3.0 mm, 3.5 mm, 4.0 mm, 4.5 mm, 5.0 mm, 5.5 mm, 6.0 mm, 6.5 mm, 7.0 mm, 7.5 mm, 8.0 mm, 8.5 mm, 9.0 mm, 9.5 mm, or 10.0 mm. Alternatively, the intervals between the determination of the inner diameter 108D of the blood vessel 108 along the site length 106L of the treatment site 106 may be different from those specifically described above. Thus, using data and / or information from the vessel diameter determination system 958 at multiple locations along the region length 106L of the treatment region 106, the vessel diameter mapping system 959 can effectively map the blood vessel 108 along the entire region length 106L of the treatment region 106. In certain embodiments, an image of the mapping of the inner diameter 108D of the blood vessel 108 along the region length 106L of the treatment region 106 may be displayed on the GUI 127 for use by the operator.

[0292] Finally, the diameter correlation system 947 can be utilized to ensure that the outer diameter 104BD of the balloon 104 and the inner diameter 108D of the blood vessel 108 are properly correlated for most effective lithotripsy and / or drug delivery at the treatment site 106. In particular, the diameter correlation system 947 can utilize data and / or information from the vessel diameter mapping system 959 regarding the inner diameter 108D of the blood vessel 108 along the site length 106L of the treatment site 106, in conjunction with data and / or information from the balloon diameter determination system 957 regarding the relationship between the outer diameter 104BD of the balloon 104 and the internal balloon pressure, to ensure that the outer diameter 104BD of the balloon 104 and the inner diameter 108D of the blood vessel 108 are properly correlated for most effective lithotripsy and / or drug delivery at the treatment site 106. More specifically, the diameter correlation system 947 and / or the system controller 126 can ensure that the balloon 104 is properly inflated (pressurized) during lithotripsy and / or drug delivery at the treatment site 106 so that the outer diameter 104BD of the balloon 104 effectively correlates with the inner diameter 108D of the blood vessel 108 at a particular location of the balloon 104 along the site length 106L of the treatment site 106.

[0293] Figure 10 is a flow chart illustrating a first (testing and / or mapping) mode of operation of the radial correlation system of Figure 9. It should be understood that any of the steps listed in the flow chart of Figure 10 may be modified, deleted, and / or combined in any suitable manner, and / or the order of the steps may be changed, without departing from the intended spirit and scope of the present invention. Also, one or more steps may be added to the sequence of steps specifically shown and described in the flow chart without departing from the intended spirit and scope of the present invention.

[0294] In step 1001, a user or operator positions a balloon catheter adjacent to the treatment site within the blood vessel to be treated. FIG. 11A illustrates a portion of one embodiment of a GUI 1127A. The GUI 1127A illustrates an image 1160A showing the placement of the catheter 102 (shown in FIG. 1 ), along with a method for ensuring proper placement of the catheter 102, balloon 104 (shown in FIG. 1 ), and / or emitter 135 (shown in FIG. 1 ) of the catheter system 100 (shown in FIG. 1 ) relative to the treatment site 106 (shown in FIG. 1 ). As used herein, the term “image” may include, by way of non-exclusive example, a still image or a video image. During an angiogram using fluoroscopy, the fluoroscopy system records images and / or video of the blood vessel 108 (shown in FIG. 1 ). The image 1160A, such as that shown in FIG. 11A , may be recorded and / or saved for reference by a physician or operator during or after the procedure. The system console 123 (shown in FIG. 1 ) and / or GUI 1127A, through use of the system controller 123, can save one or more images, such as image files (not shown), which can then be used to annotate the vessel diameter onto the image 1160A, as described herein. In certain embodiments, the system controller 123 can utilize image recognition software to determine the location(s) of radiopaque material included within the catheter 102, such as within the balloon 104, incorporated into the emitter 135, which may be provided via an optical sensor, or the like, and then annotate the image 1160A with the inner diameter of the blood vessel 108 at a particular location along the length of the treatment site 106.

[0295] Returning now to FIG. 10 , in step 1002, the balloon is inflated to a desired internal balloon pressure level. It should be understood that the initial internal balloon pressure level needs to be somewhat conservative to ensure that the outer diameter of the inflated balloon is not greater than the inner diameter of the blood vessel and thus does not overstretch the blood vessel. For example, recognizing that blood vessels in different regions of the body may have inner diameters ranging from 2 mm to 4 mm, or from 2 mm to 8 mm, the initial internal balloon pressure level for the particular balloon used may be such that the outer diameter of the balloon does not exceed approximately 2 mm. In some embodiments, the diameter correlation system may include a warning regarding the danger of possible overstretching of the blood vessel to further ensure that the initial internal balloon pressure and initial outer balloon diameter are not excessive.

[0296] In step 1003, the system controller and / or diameter correlation system uses a balloon compliance chart (corresponding to the appropriate balloon being used) to determine the outer diameter of the balloon based on the internal balloon pressure.

[0297] In step 1004, a contact detector assembly is used to determine whether there is good contact between the balloon wall and the vessel wall at the particular internal balloon pressure being applied.

[0298] If, in (optional) step 1005, the contact detector assembly determines that good contact does not exist between the balloon wall and the vessel wall at the particular internal balloon pressure being applied, the internal balloon pressure should be increased incrementally such that the outer diameter of the balloon is incrementally increased in an appropriate manner toward good contact between the balloon wall and the vessel wall while continuing to ensure that the balloon does not over-distend the vessel. For example, in certain non-exclusive embodiments, the incremental increase in internal balloon pressure may be performed such that the outer diameter of the balloon does not increase by more than 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, or 1.0 mm from one step to the next. The incremental increase in internal balloon pressure within the balloon essentially returns the procedure to step 1002, from which the procedure continues as previously described.

[0299] In step 1006, if the contact detector assembly determines that there is good contact between the balloon wall and the vessel wall at the particular internal balloon pressure being applied, the inner diameter of the vessel is recorded as equal to the outer diameter of the balloon at that particular location along the length of the treatment site.

[0300] FIG. 11B illustrates a portion of one embodiment of GUI 1127B. GUI 1127B displays image 1160B illustrating the entire region length 1161 (spanning the width of FIG. 11B) of treatment site 106 (shown in FIG. 1) with markings (shown as "X's") at specific periodic locations along region length 1161 that can indicate the inner diameter of blood vessel 108 (shown in FIG. 1) at those locations as part of a vessel diameter mapping system. As shown in FIG. 11B, in certain embodiments, a radiopaque ruler 1162 can be placed on the patient and used to take reference measurements for part or all of region length 1161 of treatment site 106 within blood vessel 108. Additionally, image 1160B displayed on GUI 1127B can be annotated with multiple annotations relating to the inner diameter of blood vessel 108 along the entire region length 1161 of treatment site 106, thereby enabling accurate measurement of the inner diameter of blood vessel 108 along the entire region length 1161 of treatment site 106 to be treated. It should be appreciated that this data can later be used to increase the likelihood that appropriately sized balloons are used during lithotripsy and / or medical therapy employed at various locations along the overall length 1161 of the treatment site 106.

[0301] 10, in step 1007, the diameter correlation system evaluates whether there are an adequate number of locations along the entire length of the treatment site within the blood vessel at which the internal diameter of the blood vessel is recorded. It should be understood that the number of locations required for purposes of determining whether there are an adequate number of locations at which the internal diameter of the blood vessel is recorded will depend, at least in part, on the complete length of the treatment site.

[0302] In (optional) step 1008, if the diameter correlation system determines that the inner diameter of the blood vessel has not been recorded at an adequate number of locations along the entire length of the treatment site, the catheter is moved to a new location within the blood vessel adjacent to the treatment site. In particular, the catheter may be moved along the length of the treatment site by an incremental distance corresponding to, for example, approximately 0.1 mm, 0.2 mm, 0.5 mm, 0.8 mm, 1.0 mm, 1.5 mm, 2.0 mm, 2.5 mm, 3.0 mm, 3.5 mm, 4.0 mm, 4.5 mm, 5.0 mm, 5.5 mm, 6.0 mm, 6.5 mm, 7.0 mm, 7.5 mm, 8.0 mm, 8.5 mm, 9.0 mm, 9.5 mm, 10.0 mm, or another appropriate value. Incremental movement of the catheter along the length of the treatment site essentially returns the procedure to step 1001, from which the procedure continues as previously described.

[0303] In step 1009, if the diameter correlation system determines that the inner diameter of the vessel has been recorded at an adequate number of locations along the entire length of the treatment site, the testing and / or mapping mode of operation for the diameter correlation system ends.

[0304] Figure 12 is a flow chart illustrating a second (therapeutic use) mode of operation of the diameter correlation system of Figure 9. It should be understood that any of the steps listed in the flow chart of Figure 12 may be modified, deleted, and / or combined in any suitable manner, and / or the order of the steps may be changed, without departing from the intended spirit and scope of the present invention. Also, one or more steps may be added to the sequence of steps specifically shown and described in the flow chart without departing from the intended spirit and scope of the present invention.

[0305] In step 1201, the physician or operator selects a catheter having an appropriately sized balloon for the purpose of the desired treatment of the treatment site. As discussed above, the appropriately sized balloon is selected based on data obtained through use of the vessel diameter mapping system. It should be understood that it may be desirable to select a catheter having an appropriately sized balloon for both the desired lithotripsy procedure and the desired blood therapy procedure for various locations along the entire length of the treatment site.

[0306] In step 1202, a catheter incorporating an appropriately sized balloon is positioned adjacent to the treatment site within the blood vessel. In step 1203, the balloon is inflated to an appropriate internal balloon pressure to ensure good contact between the balloon wall and the vessel wall, in other words, to ensure that the outer diameter of the balloon (based on data and / or information for the balloon diameter determination system) effectively correlates with the inner diameter of the vessel (based on data and / or information from the vessel diameter mapping system) at a specific location of the balloon along the entire length of the treatment site.

[0307] In step 1204, the physician or operator administers a desired treatment to the blood vessel at the treatment site. It is understood that the desired treatment may include a lithotripsy procedure and / or a medical therapy applied to the blood vessel at the treatment site.

[0308] It should be understood that these steps are repeated as many times as necessary to ensure that the desired treatment for the blood vessel is effectively applied at all appropriate and / or desired locations along the entire length of the treatment site.

[0309] It should be noted that as used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the content and / or context clearly dictate otherwise. It should also be noted that the term "or" is generally used in the sense that it includes "and / or" unless the content or context clearly dictates otherwise.

[0310] It should also be noted that, as used in this specification and the appended claims, the phrase "configured" describes a system, apparatus, or other structure that is constructed or configured to perform a particular task or adopt a particular configuration. The phrase "configured" may be used interchangeably with other similar phrases, such as arranged, configured, constructed, arranged, constructed, manufactured, arranged, etc.

[0311] The headings used herein are provided for consistency with recommendations under 37 CFR 1.77 or to otherwise provide an organizational guide. These headings should not be construed as limiting or characterizing the invention(s) set forth in any claims that may issue from this disclosure. By way of illustration, a description of technology in the "Background" section is not an admission that that technology is prior art with respect to any invention(s) in this disclosure. Neither the "Summary" nor the "Abstract" should be considered to characterize the invention(s) set forth in the claims that may issue.

[0312] The embodiments described herein are not intended to be exhaustive or to limit the invention to the precise form disclosed in the detailed description provided herein. Rather, the embodiments are chosen and described so that others skilled in the art can appreciate and understand its principles and practices. Thus, aspects have been described with reference to various specific and preferred embodiments and techniques. However, it should be understood that many variations and modifications may be made while remaining within the spirit and scope of the description.

[0313] Although several different embodiments of the catheter system, diameter correlation system, and / or contact detector assembly have been illustrated and described herein, it will be understood that one or more features of any one embodiment may be combined with one or more features of one or more of the other embodiments, provided such combinations remain within the scope of the present invention.

[0314] While several exemplary aspects and embodiments of the catheter system, diameter correlation system, and / or contact detector assembly have been discussed above, those skilled in the art will recognize certain modifications, permutations, additions, and subcombinations thereof. Accordingly, the following appended claims and any claims thereafter introduced are intended to be construed to include all such modifications, permutations, additions, and subcombinations that fall within the true spirit and scope thereof, and no limitations are intended to the details of construction or design shown herein.

Claims

1. 1. A catheter system for treating a treatment site within or adjacent to a vessel wall of a blood vessel, comprising: a balloon positionable substantially adjacent to a vessel wall at a treatment site, the balloon having a balloon wall defining a balloon interior; a first assembly illumination source that generates a first assembly illumination beam that moves in a first direction toward the interior of the balloon; a contact detector assembly configured to optically analyze a first return energy beam traveling from inside the balloon in a second direction opposite the first direction, the contact detector assembly configured to analyze the first return energy beam to determine a contact condition between the balloon wall and a blood vessel wall.

2. 10. The catheter system of claim 1, wherein the balloon is configured to receive and retain a catheter fluid within the balloon interior, and the catheter system further comprises a pressure sensor assembly including a pressure sensor configured to sense an internal balloon pressure of the catheter fluid within the balloon interior.

3. The catheter system of claim 2 , wherein the pressure sensor is in fluid communication with the catheter fluid held within the balloon interior.

4. The catheter system according to claim 2 or 3, wherein the pressure sensor is disposed inside the balloon.

5. 4. The catheter system of claim 2, further comprising a handle assembly coupled to the balloon, the handle assembly being spaced apart from the balloon, the handle assembly being usable by a user to operate the catheter system, and the pressure sensor being disposed within the handle assembly.

6. The catheter system according to claim 2 or 3, further comprising a catheter shaft, the balloon being connected to the catheter shaft, and the pressure sensor being disposed within the catheter shaft.

7. The catheter system according to claim 2 or 3, further comprising a fluid pump for holding the catheter fluid introduced into the balloon, wherein the pressure sensor is disposed in the fluid pump.

8. The catheter system according to claim 2 or 3, further comprising an inflation conduit for introducing the catheter fluid into the interior of the balloon, the pressure sensor being disposed in the inflation conduit.

9. The catheter system according to any one of claims 2 to 8, wherein the pressure sensor is selected from the group consisting of an optical fiber sensor, a diaphragm sensor, and a MEMS sensor.

10. 10. The catheter system according to claim 2, further comprising: a balloon compliance chart that plots the outer diameter of the balloon against the internal balloon pressure; and a balloon diameter determination system that determines the outer diameter of the balloon based on the sensed internal balloon pressure and the balloon compliance chart.

11. The catheter system of claim 10, further comprising a graphic user interface configured to visually display the outer diameter of the balloon.

12. 11. The catheter system of claim 10, wherein the contact detector assembly is configured to analyze the first return energy beam to determine when good contact exists between the balloon wall and a vessel wall.

13. 13. The catheter system of claim 12, further comprising a vessel diameter determination system configured to determine an inner diameter of a blood vessel, wherein when the contact detector assembly determines that good contact exists between the balloon wall and a blood vessel wall, the vessel diameter determination system determines that the inner diameter of the blood vessel is equal to the outer diameter of the balloon.

14. 14. The catheter system of claim 13, wherein the treatment site has a site length, and the vessel diameter determination system is configured to determine an inner diameter of the blood vessel at a plurality of locations along the site length of the treatment site.

15. 15. The catheter system of claim 14, wherein the locations along the length of the treatment site are spaced apart from one another by at least about 0.5 millimeters.

16. 16. The catheter system of claim 14, further comprising a vessel diameter mapping system including an image of a treatment site in a vessel wall of a blood vessel, wherein an inner diameter of the blood vessel at the plurality of locations along a length of the treatment site is annotated onto the image of the treatment site using the vessel diameter mapping system.

17. 17. The catheter system of claim 16, further comprising a graphic user interface configured to visually display (i) an outer diameter of the balloon and (ii) the image of the treatment site including the annotation of an inner diameter of a blood vessel at the plurality of locations along a length of the treatment site.

18. 18. The catheter system of claim 16 or 17, further comprising: a system controller including one or more processors; and a diameter correlation system at least partially integrated within the system controller, wherein the diameter correlation system is configured to use data from the balloon diameter determination system regarding the outer diameter of the balloon and data from the vessel diameter determination system regarding the inner diameter of the vessel at the plurality of locations along a length of a treatment site to ensure proper correlation between the outer diameter of the balloon and the inner diameter of a vessel during use of the catheter system in a therapeutic procedure.

19. 20. The catheter system of claim 18, wherein the system controller controls the internal balloon pressure of the catheter fluid within the balloon to ensure proper correlation between the outer diameter of the balloon and the inner diameter of a blood vessel during use of the catheter system in a therapeutic procedure.

20. 20. The catheter system of claim 1, further comprising a beam guide, wherein the first assembly illumination beam travels in the first direction through the beam guide from a guide proximal end to a guide distal end disposed within the balloon interior, and the first return energy beam travels in the second direction through the beam guide from the guide distal end to the guide proximal end.

21. 21. The catheter system of claim 20, wherein the first assembly illumination beam includes a first light energy and the first return energy beam includes a second light energy from at least a portion of the first light energy reflected from a blood vessel wall.

22. 22. The catheter system of claim 20, further comprising a second assembly illumination source generating a second assembly illumination beam traveling in the first direction toward an interior of the balloon, wherein the contact detector assembly is configured to optically analyze a second return energy beam from the interior of the balloon traveling in the second direction opposite the first direction, and the contact detector assembly is configured to analyze the first return energy beam and the second return energy beam to determine a contact state between the balloon wall and a blood vessel wall.

23. 23. The catheter system of claim 22, wherein the second assembly illumination beam travels in the first direction through the beam guide from the guide proximal end to the guide distal end disposed within the balloon interior, and the second return energy beam travels in the second direction through the beam guide from the guide distal end to the guide proximal end.

24. 24. The catheter system of claim 23, wherein the second assembly illumination beam includes first light energy and the second return energy beam includes second light energy from at least a portion of the first light energy from the second assembly illumination beam reflected from blood located between the balloon wall and a blood vessel wall.

25. 25. The catheter system of claim 22, wherein the first assembly illumination beam is at a first wavelength and the second assembly illumination beam is at a second wavelength different from the first wavelength.

26. 26. The catheter system of claim 25, wherein the first assembly illumination beam and the second assembly illumination beam are transmitted sequentially through the beam guide from the proximal guide end to the distal guide end.

27. 27. The catheter system of claim 26, wherein the first return energy beam travels in the second direction through the beam guide from the guide distal end to the guide proximal end, and thereafter the second assembly illumination beam travels in the first direction through the beam guide from the guide proximal end to the guide distal end.

28. 26. The catheter system of claim 25, wherein the first assembly illumination beam and the second assembly illumination beam travel substantially simultaneously through the beam guide as a combined illumination beam from the proximal guide end to the distal guide end.

29. 30. The catheter system of claim 28, wherein the first return energy beam and the second return energy beam travel substantially simultaneously through the beam guide from the distal guide end to the proximal guide end as a combined return energy beam.

30. The catheter system according to any one of claims 20 to 29, further comprising an energy source that generates a light source beam directed into the interior of the balloon.

31. The catheter system of claim 30 , wherein the energy source is a light source.

32. 32. The catheter system of claim 31, wherein the light source is an infrared laser.

33. 33. The catheter system according to claim 30, wherein the light source beam is directed through the beam guide from the proximal guide end to the distal guide end disposed within the balloon.

34. 31. The catheter system of claim 30, further comprising an energy guide separate from the beam guide, the light source beam being directed through the energy guide from a proximal guide end to a distal guide end disposed within the balloon interior.

35. 35. The catheter system of claim 34, wherein the energy source is a light source and the energy guide is a light guide.

36. 36. The catheter system of claim 35, wherein the light source is an infrared laser.

37. 35. The catheter system of claim 34, wherein the energy source is a high-voltage energy source that supplies high-voltage pulses.

38. 38. The catheter system of claim 37, wherein the energy guide includes an electrode pair including spaced apart electrodes extending within the balloon interior, and high voltage pulses from the energy source are applied to the electrodes to form an electrical arc between the electrodes.

39. 39. The catheter system according to claim 30, wherein the balloon is configured to receive and hold a catheter fluid within the balloon interior, and the light source beam directed toward the balloon interior induces plasma generation in the catheter fluid within the balloon interior.

40. 40. The catheter system of claim 39, wherein the generation of the plasma causes rapid bubble formation and imparts a pressure wave to the balloon wall adjacent the treatment site.

41. 41. The catheter system of claim 20, wherein the contact detector assembly includes a beam splitter and a photodetector, the beam splitter configured to receive return energy that has traveled through the beam guide in the second direction from the guide distal end to the guide proximal end and to direct at least a portion of the return energy to the photodetector.

42. 42. The catheter system of claim 41, wherein the contact detector assembly further includes an optical element disposed along a beam path between the beam splitter and the photodetector, the optical element configured to couple a portion of the returned energy to the photodetector.

43. 43. The catheter system of claim 41 or 42, wherein the photodetector generates a signal based at least in part on the portion of the returned energy directed to the photodetector.

44. 44. The catheter system of claim 43, wherein the signal from the photodetector is amplified by an amplifier to provide an amplified signal directed to control electronics for determining contact conditions between the balloon wall and a vessel wall.

45. 1. A catheter system for treating a treatment site within or adjacent to a heart valve, comprising: a balloon positionable substantially adjacent to the heart valve at the treatment site, the balloon having a balloon wall defining a balloon interior; a first assembly illumination source that generates a first assembly illumination beam that moves in a first direction toward the interior of the balloon; a contact detector assembly configured to optically analyze a first return energy beam traveling from inside the balloon in a second direction opposite the first direction, the contact detector assembly configured to analyze the first return energy beam to determine a contact state between the balloon wall and a heart valve.

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