Imaging probe with fluid pressurization element

Abstract

To reduce nonuniform rotation of an optical assembly rotatably disposed within an imaging probe.SOLUTION: The imaging probe includes an elongated shaft, a rotatable optical core, an optical assembly, a damping fluid, and a fluid pressurization element. The elongated shaft includes a proximal end, a distal end, and a lumen extending between the proximal end and the distal end. The rotatable optical core includes a proximal end and a distal end. At least a portion of the rotatable optical core is disposed within the lumen of the elongated shaft. The optical assembly is disposed proximate to the distal end of the rotatable optical core, and is configured to direct light to tissue and collect reflected light from the tissue. The damping fluid is disposed between the elongated shaft and the rotatable optical core, and is configured to reduce nonuniform rotation of the optical assembly. The fluid pressurization element increases the pressure of the damping fluid to reduce the presence of air bubbles that are closer to the optical assembly.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present concepts relate generally to imaging systems, and more particularly to intravascular imaging systems that include an imaging probe and a delivery device. [Background technology]

[0002] Imaging probes have been commercialized for imaging various locations within a patient's body, such as intravascular probes for imaging a patient's heart. Current imaging probes are limited in their ability to reach certain anatomical locations due to their size and stiffness. Current imaging probes are inserted over a guidewire, which may limit the placement of the probe and the use of one or more delivery catheters through which the imaging probe is inserted. Thus, there is a need for imaging systems including small diameter, flexible probes, and systems having one or more delivery devices that are compatible with these improved imaging probes. Summary of the Invention

[0003] In accordance with one aspect of the inventive concept, an imaging system for a patient includes an imaging probe comprising an elongate shaft including a proximal end, a distal portion, and a lumen extending between the proximal end and the distal portion, a rotatable optical core including a proximal end and a distal end, where at least a portion of the rotatable optical core is disposed within the lumen of the elongate shaft, an optical assembly disposed proximate the distal end of the rotatable optical core and configured to direct light to tissue and collect reflected light from the tissue, a damping fluid disposed between the elongate shaft and the rotatable optical core and configured to reduce uneven rotation of the optical assembly, a fluid pressurizing element configured to increase pressure of the damping fluid to reduce the presence of air bubbles proximate the optical assembly, and an imaging assembly configured and arranged to optically couple to the imaging probe, to illuminate the imaging probe, and to receive reflected light collected by the optical assembly.

[0004] In some embodiments, the fluid pressurizing element is configured to reduce the formation of air bubbles.

[0005] In some embodiments, the fluid pressurizing element is configured to reduce the growth of one or more gas bubbles.

[0006] In some embodiments, the fluid pressurizing element is configured to reduce the size of one or more gas bubbles.

[0007] In some embodiments, the system comprises an optical beam path, and the fluid pressurizing element is configured to propel the one or more gas bubbles away from the optical beam path.

[0008] In some embodiments, the fluid pressurizing element is configured to create a pressure gradient in the damping fluid.

[0009] In some embodiments, the fluid pressurizing element is configured to increase the pressure of the damping fluid for a limited period of time.

[0010] In some embodiments, the fluid pressurizing element is configured to increase the pressure of the damping fluid intermittently. The fluid pressurizing element can be configured to increase the pressure of the damping fluid only when imaging is possible. The fluid pressurizing element can be configured to increase the pressure of the damping fluid only when the rotatable optical core rotates. The fluid pressurizing element can be configured to increase the pressure of the damping fluid for discrete periods of time of 2 minutes or less. The fluid pressurizing element can be configured to increase the pressure of the damping fluid for discrete periods of time of 30 seconds or less. The fluid pressurizing element can be configured to increase the pressure of the damping fluid for discrete periods of time of 5 seconds or less.

[0011] In some embodiments, the fluid pressurizing element is configured to generate a pressure in the damping fluid of at least 3.6 psi, 5.0 psi, 10 psi, 15 psi, 20 psi, 30 psi, and / or 40 psi.

[0012] In some embodiments, the fluid pressurizing element is configured to generate a pressure in the damping fluid of at least 75 psi, 100 psi, 125 psi, and / or 150 psi.

[0013] In some embodiments, the fluid pressurizing element is configured to create regions of high pressure and low pressure within the damping fluid.

[0014] In some embodiments, the fluid pressurizing element comprises a pressurized source. The pressurized source may comprise a pump. The fluid pressurizing element may further comprise a valve configured to allow the passage of gas while restricting the passage of damping fluid.

[0015] In some embodiments, the fluid pressurizing element is configured to increase the pressure of the damping fluid when the rotatable optical core rotates. The fluid pressurizing element may include at least one protrusion extending radially from the rotatable optical core. The at least one protrusion may include a plurality of protrusions, each protrusion extending radially from the rotatable optical core. The fluid pressurizing element may include a helical protrusion extending radially from the rotatable optical core. The fluid pressurizing element may comprise a helical coil surrounding the rotatable optical core. The helical coil may have a uniform pitch. The fluid pressurizing element may comprise an element having a propeller-like structure. The fluid pressurizing element may comprise a spring-type element.

[0016] In some embodiments, the fluid pressurizing element comprises a first fluid pressurizing element and a second fluid pressurizing element, the second fluid pressurizing element being disposed proximal to the first fluid pressurizing element, the second fluid pressurizing element being configured to prime the first fluid pressurizing element when rotated.

[0017] In some embodiments, the fluid pressurizing element is adhesively attached to the rotatable optical core.

[0018] In some embodiments, the fluid pressurizing element is molded onto and / or with the rotatable optical core.

[0019] In some embodiments, the fluid pressurizing element is fused to the rotatable optical core.

[0020] In some embodiments, the fluid pressurizing element is formed on the rotatable optical core. The system can be formed on the rotatable optical core via deposition and / or three-dimensional (3D) printing.

[0021] In some embodiments, the fluid pressurizing element comprises a material selected from the group consisting of metal, plastic, stainless steel, nickel-titanium alloy, nylon, polyetheretherketone, polyimide, and combinations thereof.

[0022] In some embodiments, the rotatable optical core has a diameter D1, the elongate shaft lumen has a diameter D2, and the fluid pressurizing element extends from the rotatable optical core at a radial height H1, where H1 is at least 5% and / or no more than 95% of half the difference between D1 and D2.

[0023] In some embodiments, the rotatable optical core has a diameter D1, the elongate shaft lumen has a diameter D2, the fluid pressurizing element extends from the rotatable optical core at a radial height H1, and a clearance C1 has a value equal to half the difference between D1 and D2 minus H1, and the clearance C1 has a length equal to or less than 100 μm and / or equal to or less than 75 μm.

[0024] In some embodiments, the fluid pressurizing element comprises a coating, which may comprise a member selected from the group consisting of a sheath, a heat shrink tubing, a painted coating, a sprayed coating, and combinations thereof.

[0025] In some embodiments, the fluid pressurizing element is further configured to generate a motive force configured to translate the rotatable optical core. The fluid pressurizing element can be configured to advance the rotatable optical core when rotated in a first direction and to retract the rotatable optical core when rotated in a second direction opposite the first direction.

[0026] In some embodiments, the damping fluid comprises a non-Newtonian fluid.

[0027] In some embodiments, the damping fluid comprises a shear thinning fluid.

[0028] In some embodiments, the damping fluid has a static viscosity of at least 500 centipoise. The damping fluid may have a shear viscosity that is less than its static viscosity. The damping fluid may have a static viscosity to shear viscosity ratio of at least 1.2:1 and / or less than or equal to 100:1.

[0029] In some embodiments, the damping fluid comprises a first fluid and a second fluid, The first fluid may comprise a low viscosity fluid and the second fluid may comprise a high viscosity fluid.

[0030] In some embodiments, the damping fluid comprises a low viscosity fluid configured to reduce the formation of air bubbles. The damping fluid may comprise a fluid having a viscosity of 1000 centipoise or less.

[0031] In some embodiments, the damping fluid comprises a fluid having a high surface tension configured to reduce bubble formation. The damping fluid may comprise a fluid having a surface tension of at least 40 dynes / cm.

[0032] In some embodiments, the imaging probe comprises a distal portion having a diameter of 0.020 inches or less. The distal portion of the imaging probe may have a diameter of 0.016 inches or less.

[0033] In some embodiments, the imaging probe further includes a sealing element at a distal portion of the elongate shaft.

[0034] According to another aspect of the inventive concept, an imaging probe includes an elongate shaft including a proximal end, a distal portion, and a lumen extending between the proximal end and the distal portion, a rotatable optical core including a proximal end and a distal end, and an optical assembly, where at least a portion of the rotatable optical core is disposed within the lumen of the elongate shaft and disposed proximate the distal end of the rotatable optical core, configured to direct light to tissue and collect reflected light from the tissue. The shaft includes a proximal shaft and a distal shaft attached thereto. The proximal shaft includes a first tubular member having a first lumen. The distal shaft includes a second tubular member having a second lumen. The shaft further includes a third tubular member extending into the first lumen and the second lumen. The shaft further includes a fourth tubular member having a proximal portion surrounding the distal portion of the first tubular member and a distal portion located between the proximal portion of the second tubular member and the third tubular member.

[0035] In some embodiments, the first tubular member comprises a spiral cut hypotube.

[0036] In some embodiments, the second tubular member comprises a transparent material.

[0037] In some embodiments, the third tubular member has a larger outer diameter than the first lumen.

[0038] In some embodiments, the fourth tubular member comprises a heat shrink material.

[0039] In some embodiments, the imaging probe further comprises an adhesive disposed between two or more of the first tubular member, the second tubular member, the third tubular member, and / or the fourth tubular member.

[0040] In some embodiments, the imaging probe further comprises a fluid propulsion element having a diameter D1, and the third tubular member comprises a lumen having a diameter smaller than D1.

[0041] In some embodiments, the second tubular member includes a protrusion extending toward the third tubular member.

[0042] In some embodiments, the second tubular member has a maximum diameter adjacent to the third tubular member and the fourth tubular member has a maximum diameter adjacent to the third tubular member, each maximum diameter not exceeding a diameter of 0.02 inches, 0.0175 inches, and / or 0.0155 inches.

[0043] In some embodiments, the fluid pressurizing element comprises a first fluid pressurizing element and a second fluid pressurizing element, the first and second fluid pressurizing elements being capable of creating opposing pressure gradients when rotated.

[0044] According to another aspect of the present invention, a method of manufacturing a fluid propulsion element for an optical probe includes providing a tube with a mandrel inserted therein, forming two or more helical channels along a length of the tube, removing a first fluid propulsion element from the mandrel, and removing a second fluid propulsion element from the mandrel.

[0045] In some embodiments, the method further comprises generating a first optical probe using at least a first fluidic driving element. The method can further comprise generating a second optical probe using a second fluidic driving element.

[0046] The technology described herein, together with its features and attendant advantages, will best be understood in view of the following detailed description taken in conjunction with the accompanying drawings in which exemplary embodiments are set forth, by way of example.

[0047] <Incorporated by reference> All publications, patents, and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference. The contents of all publications, patents, and patent applications mentioned in this specification are incorporated by reference in their entirety for all purposes.

[0048] <Related Applications> This application claims the benefit of U.S. Provisional Application Serial No. 62 / 840,450, entitled “Imaging Probe with Fluid Pressurization Element,” filed April 30, 2019, the contents of which are incorporated by reference in their entirety.

[0049] This application claims the benefit of U.S. Provisional Application Serial No. 63 / 017,258, entitled "Imaging System," filed April 29, 2020, the contents of which are incorporated by reference in their entirety.

[0050] This application claims the benefit of U.S. Provisional Application Serial No. 62 / 850,945, entitled “OCT-Guided Treatment of a Patient,” filed May 21, 2019, the contents of which are incorporated by reference in their entirety.

[0051] This application claims the benefit of U.S. Provisional Application Serial No. 62 / 906,353, entitled “OCT-Guided Treatment of a Patient,” filed September 26, 2019, the contents of which are incorporated by reference in their entirety.

[0052] This application is related to U.S. Provisional Application Serial No. 62 / 148,355, entitled "Micro-Optic Probes for Neurology," filed April 16, 2015, the contents of which are incorporated by reference in their entirety.

[0053] This application is related to U.S. Provisional Application Serial No. 62 / 322,182, entitled "Micro-Optic Probes for Neurology," filed April 13, 2016, the contents of which are incorporated by reference in their entirety.

[0054] This application is related to International PCT Patent Application Serial No. PCT / US2016 / 027764, entitled "Micro-Optic Probes for Neurology," filed April 15, 2016, publication number WO 2016 / 168605, published October 20, 2016, the contents of which are incorporated by reference in their entirety.

[0055] This application is related to U.S. Patent Application Serial No. 15 / 566,041, entitled "Micro-Optic Probes for Neurology," filed October 12, 2017, and U.S. Publication No. 2018-0125372, published May 10, 2018, the contents of which are incorporated by reference in their entirety.

[0056] This application is related to U.S. Provisional Application Serial No. 62 / 212,173, entitled "Imaging System Includes Imaging Probe and Delivery Devices," filed on August 31, 2015, the contents of which are incorporated by reference in their entirety.

[0057] This application is related to U.S. Provisional Application Serial No. 62 / 368,387, entitled "Imaging System Includes Imaging Probe and Delivery Devices," filed on July 29, 2016, the contents of which are incorporated by reference in their entirety.

[0058] This application is related to International PCT Patent Application Serial No. PCT / US2016 / 049415, entitled "Imaging System Includes Imaging Probe and Delivery Devices," filed August 30, 2016, and Publication No. WO 2017 / 040484, published March 9, 2017, the contents of which are incorporated by reference in their entirety.

[0059] This application is related to U.S. patent application Ser. No. 15 / 751,570, entitled "Imaging System Includes Imaging Probe and Delivery Devices," filed February 9, 2018, and U.S. Patent No. 10,631,718, issued April 28, 2020, the contents of which are incorporated by reference in their entirety.

[0060] This application is related to U.S. Provisional Application Serial No. 62 / 591,403, entitled "Imaging System," filed November 28, 2017, the contents of which are incorporated by reference in their entirety.

[0061] This application is related to U.S. Provisional Application Serial No. 62 / 671,142, entitled "Imaging System," filed May 14, 2018, the contents of which are incorporated by reference in their entirety.

[0062] This application is related to International PCT Patent Application Serial No. PCT / US2018 / 062766, entitled "Imaging System," filed November 28, 2018, and Publication No. WO2019 / 108598, published June 6, 2019, the contents of which are incorporated by reference in their entirety.

[0063] This application is related to U.S. Provisional Application Serial No. 62 / 732,114, entitled "Imaging System with Optical Pathway," filed September 17, 2018, the contents of which are incorporated by reference in their entirety.

[0064] This application is related to International PCT Patent Application Serial No. PCT / US2019 / 051447, entitled "Imaging System with Optical Pathway," filed September 17, 2019, and Publication No. WO 2020 / 0611001, published March 26, 2020, the contents of which are incorporated by reference in their entirety. [Brief description of the drawings]

[0065] [Figure 1] 1 is a schematic diagram of an imaging system including an imaging probe having a fluid pressurizing element consistent with the concepts of the present invention; [Figure 1A] FIG. 2 is an enlarged view of the components within circle M1 of FIG. 1 consistent with the concepts of the present invention. [Diagram 2]1 is a schematic diagram of a distal portion of an imaging probe and delivery catheter consistent with the concepts of the present invention. [Figure 2A] FIG. 1 is an enlarged view of components within circle M2 consistent with the concepts of the present invention. [Figure 2B] 1 is a schematic diagram of a distal portion of an imaging probe showing fluid flow patterns consistent with the concepts of the present invention. [Figure 2C] 1 shows a simulation of a fluid flow consistent with the concepts of the present invention. [Figure 3A] 1 is a schematic diagram of a distal portion of an imaging probe consistent with the concepts of the present invention; [Figure 3B] 1 is a schematic diagram of a distal portion of an imaging probe consistent with the concepts of the present invention; [Figure 4] 1 is a schematic diagram of a distal portion of an imaging probe and delivery catheter consistent with the concepts of the present invention. [Figure 4A] FIG. 13 is an enlarged view of the components within circle M3 consistent with the concept of the present invention. [Diagram 5] 1 is a schematic diagram of a distal portion of an imaging probe and delivery catheter consistent with the concepts of the present invention. [Figure 5A] FIG. 1 is an enlarged view of the components within circle M4 consistent with the concept of the present invention. [Figure 6A] 1 is a schematic diagram of a distal portion of an optical probe consistent with the concepts of the present invention. [Figure 6B] 1 is a schematic diagram of a distal portion of an optical probe consistent with the concepts of the present invention. [Figure 6C] 1 is a schematic diagram of a distal portion of an optical probe consistent with the concepts of the present invention. [Figure 7] 1 is a cross-sectional view of a segment of an imaging probe having a shaft with a multi-component construction consistent with the concepts of the present invention; [Figure 8] 1 is a cross-sectional view of a portion of an imaging probe including a bi-directional fluid propulsion element consistent with the concepts of the present invention; [Figure 9A] 1A-1D are perspective views of four steps of a process for manufacturing a fluid propulsion element consistent with the concepts of the present invention. [Figure 9B]1A-1D are perspective views of four steps of a process for manufacturing a fluid propulsion element consistent with the concepts of the present invention. [Figure 9C] 1A-1D are perspective views of four steps of a process for manufacturing a fluid propulsion element consistent with the concepts of the present invention. [Figure 9D] 1A-1D are perspective views of four steps of a process for manufacturing a fluid propulsion element consistent with the concepts of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0066] Reference will now be made in detail to the present embodiments of the present technology, examples of which are illustrated in the accompanying drawings. Like reference numerals may be used to refer to like elements. However, this description is not intended to limit the disclosure to the particular embodiments, which should be construed to include various modifications, equivalents, and / or alternatives to the embodiments described herein.

[0067] It is understood that the words "comprising" (and any form of comprising, such as "comprise" or "comprises"), "having" (and any form of having, such as "have" or "has"), "including" (and any form of including, such as "includes" or "include"), or "containing" (and any form of containing, such as "contains" or "contain") are used herein to specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0068] Furthermore, although terms such as first, second, third, etc. may be used herein to describe various limitations, elements, components, regions, layers, and / or sections, it is understood that these limitations, elements, components, regions, layers, and / or sections should not be limited by these terms. These terms are used only to distinguish one limitation, element, component, region, layer, or section from another limitation, element, component, region, layer, or section. Thus, a first limitation, element, component, region, layer, or section described below can be referred to as a second limitation, element, component, region, layer, or section without departing from the teachings of the present application.

[0069] It is further understood that when an element is referred to as "on," "attached," "connected," or "coupled" to another element, the element is directly on or on, connected to, or coupled to the other element, or one or more intervening elements may be present. On the other hand, when an element is referred to as "directly on," "directly attached," "directly connected," or "directly coupled" to another element, there are no intervening elements present. Other words used to describe the relationship between elements should be interpreted similarly (e.g., "between" vs. "direct between," "adjacent" vs. "direct adjacent," etc.).

[0070] Furthermore, when a first element is referred to as being "in," "on," and / or "within" a second element, it is understood that the first element can be disposed within an interior space of the second element, a portion of the second element (e.g., within a wall of the second element), an exterior and / or interior surface of the second element, and any combination of one or more of these.

[0071] As used herein, the term "proximate" when used to describe a first component or location being proximate to a second component or location should be interpreted to include one or more locations near the second component or location, as well as locations within, on, and / or within the second component or location. For example, a component located proximate to an anatomical site (e.g., the location of a target tissue) is intended to include not only a component located proximate to the anatomical site, but also a component located within, on, and / or within the anatomical site.

[0072] Spatially relative terms such as "below," "lower," "bottom," "top," and the like may be used to describe the relationship of one element and / or feature to another element and / or feature, for example, as illustrated in the figures. It is further understood that the spatially relative terms are intended to encompass different orientations of the device during use and operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements that are described as "below" and / or "below" other elements or features would then be oriented "above" the other elements or features. The device may be otherwise oriented (e.g., rotated 90 degrees or otherwise oriented) and the spatially relative descriptors used herein would be interpreted accordingly.

[0073] As used herein, the terms "reduce," "reducing," "reduction," and the like are intended to include the reduction of a quantity, including reduction to zero. Reducing the likelihood of occurrence is intended to include the prevention of occurrence. Correspondingly, the terms "prevent," "preventing," and "prevention" are intended to include the acts of "reduce," "reduction," and "reduction," respectively.

[0074] As used herein, the term "and / or" is deemed to specifically disclose each of the two specified features or components with or without the other. For example, "A and / or B" is deemed to specifically disclose each of (i) A, (ii) B, and (iii) A and B, as if each were individually set forth herein.

[0075] As used herein, the term "one or more" can mean up to any number, such as one, two, three, four, five, six, seven, eight, nine, ten, or more.

[0076] The terms "and combinations thereof" and "and combinations thereof," each may be used herein following a list of items to be included, either singly or collectively, e.g., components, processes, and / or other items selected from the group consisting of: A; B; C; and combinations thereof, shall include a set of one or more components consisting of one, two, three or more of item A, one, two, three or more of item B, and / or one, two, three or more of item C.

[0077] As used herein, "and" means "or," and "or" can mean "and," unless otherwise indicated. For example, if a feature is described as having A, B, or C, the feature can have A, B, and C, or any combination of A, B, and C; similarly, if a feature is described as having A, B, and C, the feature can have only one or two of A, B, or C.

[0078] The phrase "configured (or configured) to" as used in this disclosure may be used interchangeably with, for example, "suitable for," "capable of," "designed to," "adapted for," "has been," or "can," depending on the context. Also, the phrase "configured (or configured) to" does not only mean "specially designed to" in terms of hardware. Alternatively, depending on the context, the phrase "a device configured to" may mean that the device is "capable" of operating with other devices or components.

[0079] As used herein, the term "threshold" refers to a maximum level, a minimum level, and / or a range of values ​​associated with a desired or undesirable condition. In some embodiments, a system parameter is maintained above a minimum threshold, below a maximum threshold, within a threshold range, and / or outside a threshold range to cause a desired effect (e.g., effective treatment) and / or prevent or otherwise reduce (hereinafter "prevent") an undesirable event (e.g., adverse device and / or clinical events). In some embodiments, a system parameter is maintained above a first threshold (e.g., above a first temperature threshold to cause a desired therapeutic effect on tissue) and below a second threshold (e.g., below a second temperature threshold to prevent undesirable tissue damage). In some embodiments, the thresholds are determined to include a safety margin, taking into account patient variability, system variability, tolerances, etc. As used herein, "above a threshold" refers to a parameter being above a maximum threshold, below a minimum threshold, within a threshold range, and / or outside a threshold range.

[0080] As used herein, "room pressure" is intended to mean the pressure of the environment surrounding the systems and devices of the inventive concept. Positive pressure includes pressures above room temperature or simply pressures above other pressures, such as a positive pressure differential across a fluid path component such as a valve. Negative pressure includes pressures below room pressure or pressures below other pressures, such as a negative pressure differential across the path of a fluid component such as a valve. Negative pressure can include a vacuum, but does not mean a pressure below a vacuum. As used herein, the term "vacuum" can be used to refer to a full or partial vacuum, or any negative pressure as described above.

[0081] The term "diameter" as used herein to describe non-circular shapes is considered to be the diameter of an imaginary circle that approximates the shape being described. When describing a cross-section, such as a cross-section of a part, the term "diameter" is intended to represent the diameter of an imaginary circle having the same cross-sectional area as the cross-section of the part being described.

[0082] The "major axis" and "minor axis" of a part herein refer to the length and diameter of an imaginary cylinder of minimum volume that can completely surround the part.

[0083] As used herein, the term "functional element" is intended to include one or more elements constructed and arranged to perform a function. A functional element may include a sensor and / or a transducer. In some embodiments, a functional element is configured to deliver energy and / or treat tissue (e.g., a functional element configured as a therapeutic element). Alternatively or additionally, a functional element (e.g., a functional element comprising a sensor) may be configured to record one or more parameters, such as a patient physiological parameter, a patient anatomical parameter (e.g., a tissue shape parameter), a patient environmental parameter, and / or a system parameter. In some embodiments, a sensor or other functional element is configured to perform a diagnostic function (e.g., collect data used to perform a diagnosis). In some embodiments, a functional element is configured to perform a therapeutic function (e.g., provide therapeutic energy and / or a therapeutic agent). In some embodiments, the functional element comprises one or more elements constructed and arranged to perform a function selected from the group consisting of: supplying energy, extracting energy (e.g., cooling a component), supplying a drug or the like, manipulating a system component or a patient's tissue, recording or otherwise sensing a parameter, such as a patient's physiological parameter or a system parameter, and combinations of one or more of the foregoing. The functional element comprises a fluid and / or a fluid delivery system. The functional element may include a reservoir, such as an expandable balloon or other fluid-holding reservoir. A "functional assembly" may comprise an assembly constructed and arranged to perform a function, such as a diagnostic and / or therapeutic function. The functional assembly may include an expandable assembly. The functional assembly may include one or more functional elements.

[0084] The term "transducer" as used herein is intended to include any component or combination of components that receives energy or some input and produces an output. For example, a transducer can include an electrode that receives electrical energy and distributes the electrical energy to tissue (e.g., based on the size of the electrode). In some configurations, a transducer converts an electrical signal into any output, such as light (e.g., a transducer made of a light emitting diode or a light bulb), sound (e.g., a transducer made of a piezo crystal configured to deliver ultrasonic energy), pressure, thermal energy, cryogenic energy, chemical energy, mechanical energy (e.g., a transducer made of a motor or a solenoid), magnetic energy, and / or another electrical signal (e.g., a Bluetooth or other wireless communication element). Alternatively or additionally, a transducer can convert a physical quantity (such as a change in a physical quantity) into an electrical signal. A transducer can include any component that delivers energy and / or an agent to tissue. For example, the transducer may be configured to deliver one or more of electrical energy to tissue (e.g., a transducer including one or more electrodes), optical energy to tissue (e.g., a transducer comprised of lasers, light emitting diodes, optical components such as lenses or prisms), mechanical energy to tissue (e.g., a transducer with a tissue manipulation element), acoustic energy to tissue (e.g., a transducer with a piezoelectric crystal), chemical energy, electromagnetic energy, magnetic energy, and combinations of one or more of these.

[0085] As used herein, the term "fluid" refers to a liquid, gas, gel, or any flowable material, eg, a material that can be propelled through a lumen and / or opening.

[0086] It will be understood that certain features of the inventive concepts, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the inventive concepts, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination. For example, it will be understood that all features recited in any of the claims (whether independent or dependent) may be combined in any manner.

[0087] It will be understood that the illustrations and descriptions of at least some of the inventive concepts have been simplified to focus on elements relevant to a clear understanding of the inventive concepts, while excluding for purposes of clarity other elements that one of ordinary skill in the art would understand may also form part of the inventive concepts, but because such elements are well known in the art and do not necessarily facilitate a better understanding of the invention, a description of such elements will not be provided herein.

[0088] The terms defined in this disclosure are used only to describe certain embodiments of the disclosure and are not intended to limit the scope of the disclosure. Terms provided in the singular are intended to include the plural, unless the context clearly indicates otherwise. All terms used herein, including technical or scientific terms, have the same meaning as commonly understood by those skilled in the relevant art, unless otherwise specifically defined herein. Terms defined in commonly used dictionaries should be interpreted to have the same or similar meaning as in the context of the relevant art, and should not be interpreted to have an ideal or exaggerated meaning, unless otherwise explicitly defined herein. In some cases, the terms defined in this disclosure should not be interpreted to exclude embodiments of the disclosure.

[0089] Provided herein is an imaging system for a patient, including an imaging probe and an imaging assembly optically coupled to the imaging probe. The probe comprises an elongated shaft, a rotatable optical core, and an optical assembly. The rotatable optical core is disposed within a lumen of the elongated shaft. The optical assembly is disposed proximate a distal end of the optical core and configured to direct light to tissue and collect reflected light from the tissue. When optically coupled to the imaging probe, the imaging assembly is configured to illuminate the imaging probe with light and receive reflected light collected by the optical assembly, for example, to provide an image of a blood vessel and a device disposed within the blood vessel. The probe can include a damping fluid disposed between the elongated shaft and the rotatable optical core, which can be configured to reduce non-uniform rotation of the optical assembly and, as a result, reduce undesirable distortion of an image generated by the system. The probe can further include a fluid pressurizing element configured to increase pressure of the damping fluid to reduce the presence of air bubbles proximate the optical assembly (e.g., air bubbles that limit or reduce the quality of an image generated by the system).

[0090] Vascular imaging is the primary diagnostic tool in planning and applying therapeutics such as thrombolytics and stent retrievers for clot removal (e.g., ischemic stroke) or coils and flow diverters for aneurysm repair (e.g., hemorrhagic stroke). External non-invasive imaging such as X-ray angiography and magnetic resonance imaging (MRI) are the primary imaging techniques, but these techniques only provide information about the size and shape of the vessel and have a moderate resolution (~0.2 mm or 200 um). Such a resolution does not allow imaging important small features present inside the vessel. The inability to adequately image these vessels limits preoperative planning and acute evaluation of treatment results. When coils are used, the effectiveness of these imaging techniques is further limited by shadows and localized image loss caused by treatments. There is therefore a desire to also perform intravascular imaging of the inventive concept to examine the detailed morphology of the vessel inner wall and / or to better plan and evaluate the results of catheter-based interventions. Currently, intravascular imaging techniques such as intravascular ultrasound (IVUS) and intravascular optical coherence tomography (OCT) have been developed and approved for use in coronary arteries. IVUS has also been used in peripheral vessels. However, intravascular imaging has not been extended to neurovasculature, except for the large carotid artery. This limitation is mainly due to two reasons: the very small size of neurovasculature, less than 1 mm in diameter, and the very high degree of tortuosity of the vessels. Therefore, there is a need for smaller and more flexible imaging probes that can safely and effectively navigate the tortuous carotid sinus to reach and image the middle cranial artery and its more distal branches and segments.

[0091] There are fundamental limitations in ultrasound resolution, especially when using small transducers, due to the inevitable beam divergence, which makes optical techniques preferred. The use of optical techniques has become highly advantageous both from a clinical performance and commercial point of view, especially with the emergence of new light sources such as broadband superluminescent light-emitting diodes (SLEDs), supercontinuum lasers, miniature swept sources, micro-optical systems, and interferometric detection of return light, using techniques such as optical coherence tomography (OCT), all of which are compatible with single-mode fibers. Furthermore, the use of single-mode fibers allows the smallest imaging probes to be considered.

[0092] Typically, to create a three-dimensional (3D) image of the vessel interior wall, light emitted by imaging optics located at the distal end of the inserted probe can be swept over the surface of the lumen by simultaneously axially moving ("pulling back") and rotating the optical fiber connected to the optics. To obtain accurate, distortion-free images, it is desirable for the rotational speed of the distal section to be uniform. For size and cost reasons, the drive motor that induces the rotation is located proximally, outside the patient, and separate from the imaging probe (e.g., configured in a reusable arrangement for use with multiple imaging probes). The fiber in the imaging probe has a natural tendency to "whip" at its distal end, a phenomenon called Non-Uniform Rotational Distortion (NURD). To overcome this undesirable effect, tightly wound spring-like coils called torque wires are used, with the fiber located at the center of the coil to reduce non-uniform rotation of the distal optics. These torque wires increase the size of the catheter (e.g., diameter) and exceed the limit of labyrinthiness, which leads to recurrence of NURD and cost. Furthermore, the torque wire is sensitive to the total amount of bending accumulated along the length of the catheter, and because the torque wire must be attached to a proximal drive source, this total amount of bending accumulated can be large (e.g., causing NURD to reappear). Since uniform rotation is required only for the optics at the distal tip, the rotation of components proximal to the distal optics does not need to be as controlled. In other words, as long as the rotation speed of the distal optics is relatively constant, the fiber can be twisted or untwisted in the proximal region in response to changes in labyrinthness without causing NURD. Thus, a configuration that uniformly controls the rotation of the distal optics without the use of a torque wire provides many advantages while avoiding many limitations.

[0093] To overcome the limitations of torque wires, damping fluids have been used to control the change in rotational speed. For example, U.S. Patent No. 6,891,984 ('984 patent) describes the use of viscous fluids to "unwind" the fiber and store rotational energy. Also, the unwinding speed is determined by the viscosity of the fluid, providing an effective feedback mechanism for rotation control. The fluid covering the lens must meet the desired optical properties, in particular an acceptable optical index to minimize cylindrical distortion, and low absorption at the operating wavelength. The liquid selected can comprise a biocompatible liquid since it is temporarily placed in the body. If it is not biocompatible, an additional layer of protection can be added to protect against undesirable single failure conditions (e.g., leak conditions).

[0094] Systems of the inventive concept may include non-Newtonian fluids and / or shear thin-walled fluids that are compatible with high speed rotation, such as those described in Applicant's co-pending U.S. patent application Ser. No. 15 / 566,041, entitled "Micro-Optic Probes for Neurology," filed on October 12, 2017.

[0095] All fluid-based rotation control solutions (e.g., fluid damping solutions) suffer from the problem of air bubbles being easily generated in the fluid. Generally, air bubbles have little effect on mechanical performance, but it is easy to see that air bubbles located in the light transmission and reception path (the "light beam path") have a significant negative effect on image quality. Air bubble formation is inherent to rotating bodies in fluids, for example a phenomenon called cavitation. Air bubbles can also be generated in fluids by nucleation at fluid-solid interfaces, but cavitation usually dominates at high speed rotation. Due to the need to orthogonalize the light beam relative to the axis of the probe, some asymmetry exists in the distal optics (e.g., a lens assembly with a beveled distal end configured to direct the light 90° from the axis of the distal end of the attached fiber), which generally tends to generate low pressure regions at high speed rotation.

[0096] Cavitation is the presence of small vapor-filled regions ("bubbles") that occurs when a liquid is subjected to a sudden change in pressure, forming cavities in areas of relatively low pressure. The systems of the present invention have several general characteristics that can be optimized to minimize cavitation and the associated formation of bubbles. For example, the geometry of the imaging probe (e.g., the space in which the damping fluid is placed) can be constructed and arranged to minimize bubble formation. The viscosity of the included damping fluid can be selected to limit bubble formation. The damping fluid can comprise a fluid with a low vapor pressure and / or low levels of dissolved gas (or gases). The damping fluid can comprise a fluid with a high surface tension (e.g., that tends to collapse bubbles). The damping fluid can comprise a fluid with a low surface tension, such as a wetting agent (e.g., where bubble formation is caused via nucleation). A low viscosity fluid tends to reduce bubble formation, but may not be enough by itself to effectively control NURD. A combination of two or more fluids (e.g., a stacked arrangement) can be used, such as where one or more sealing elements are included to keep the fluids separated. A low viscosity fluid can be placed over the distal optics (e.g., over only the distal optics) and a high viscosity fluid can be placed proximal to the low viscosity fluid and extend over a relatively long segment of the imaging probe. In some embodiments, one or more damping fluids are used, where the one or more damping fluids have a viscosity selected to reduce bubble formation, low vapor pressure, low levels of dissolved gases, low surface tension, and / or high surface tension.

[0097] In some embodiments, the pressure of the included damping fluid (or other fluid) can be increased to cause an effect selected from the group consisting of: a reduction in bubble formation, a reduction in the growth of one or more bubbles (e.g., one or more pre-existing bubbles), a reduction in the size of one or more bubbles (e.g., one or more pre-existing bubbles), a propulsion of one or more bubbles away from the optical beam path, and combinations thereof. The increased pressurization of the damping fluid can be performed for a limited time, since a prolonged pressurization can cause the fluid to adsorb additional gas and establish new vapor pressure. The pressurization elements of the inventive concept can be small in size (e.g., compact) to be contained within the probe. These pressurization elements can be activated (e.g., generating increased pressure of the damping fluid) only when actual imaging is occurring (e.g., when the fiber and distal optics are rotating at high speed) to avoid the establishment of undesirable equilibrium conditions caused by prolonged pressurization.

[0098] All of the above air bubble reduction configurations may be applied alone and / or in combination to prevent, limit, and / or reduce air bubble formation near the distal optics of the probe.

[0099] Systems of the present concept can include a probe having a fluid pressurizing element configured to "minimize the bubble effect" (e.g., reduce the presence of air bubbles in one or more locations), including preventing, limiting, and / or reducing the formation of one or more air bubbles, limiting and / or reducing the expansion of one or more air bubbles, reducing the size of one or more air bubbles, and / or moving one or more air bubbles away from the light beam path (e.g., moving one or more air bubbles away from an optical assembly that delivers light to and / or from the tissue).

[0100] With reference to FIG. 1, a schematic diagram of an imaging system is shown that includes an imaging probe having a fluid pressurizing element consistent with the concepts of the present invention. With additional reference to FIG. 1A, a close-up view of the components within circle M1 is shown that is consistent with the concepts of the present invention. The imaging system 10 is constructed and arranged to collect image data and generate one or more images based on the recorded data, such as when the imaging system 10 includes an optical coherence tomography (OCT) imaging system constructed and arranged to collect image data of an imaging location (e.g., a segment of a blood vessel, such as during a pull-back procedure). The imaging system 10 includes an imaging probe 100 that is a catheter-based probe, and a rotating assembly 500 and a retracting assembly 800, each of which can be operably attached to the imaging probe 100. The imaging system 10 can further include a console 50 configured to operably connect to the imaging probe 100, such as via the rotating assembly 500 and / or the retracting assembly 800. The imaging probe 100 can be introduced into a patient's conduit, such as a vascular conduit, via one or more delivery catheters, such as the illustrated delivery catheter 80. Additionally or alternatively, the imaging probe 100 can be introduced through an introducer device, such as an endoscope, arthroscope, balloon dilator, or the like. In some embodiments, the imaging probe 100 is configured to be introduced into a conduit selected from the group consisting of: an artery, a vein, an artery in or adjacent to the heart, a vein in or adjacent to the heart, an artery in or adjacent to the brain, a vein in or adjacent to the brain, a peripheral artery, a peripheral vein, via a natural body orifice into a conduit, such as the esophagus, via a surgically created orifice into a body cavity, such as the abdomen, and combinations of one or more of the above. The imaging system 10 can further include additional imaging devices, such as the illustrated second imaging device 15. The imaging system 10 can further include a device configured to treat the patient, a treatment device 16.Imaging system 10 may further include a fluid injector, such as injector 20, which may be configured to inject one or more fluids, such as a flushing fluid, an imaging contrast agent (e.g., a radiopaque contrast agent, hereafter “contrast agent”), and / or other fluids, such as the illustrated injectate 21. Imaging system 10 may further include an implant, such as implant 31, which may be implanted in a patient via a delivery device, such as implant delivery device 30 and / or delivery catheter 80.

[0101] In some embodiments, the imaging probe 100 and / or other components of the imaging system 10 may be similarly constructed and arranged as similar components described in Applicant's co-pending U.S. patent application Ser. No. 15 / 566,041, entitled "Micro-Optic Probes for Neurology," filed Oct. 12, 2017, and / or Applicant's co-pending U.S. provisional patent application Ser. No. 62 / 732,114, entitled "Imaging System with Optical Pathway," filed Sep. 17, 2018. The imaging probe 100 may be constructed and arranged to collect image data from a patient site, such as an intravascular cardiac site, an intracranial site, or other site accessible via the patient's vasculature. In some embodiments, the imaging system 10 may be constructed and arranged similarly to similar systems and methods of use described in Applicant's co-pending U.S. patent application Ser. No. 15 / 751,570, entitled "Imaging System Includes Imaging Probe and Delivery Devices," filed on February 9, 2018.

[0102] The delivery catheter 80 comprises a shaft 81, which is an elongate shaft, a lumen 84 therein, and a connector 82 disposed at its proximal end. The connector 82 may comprise a Touhy or other valved connector, such as a valved connector configured to prevent the exit of fluids from an associated delivery catheter 80 (with and / or without a separate shaft disposed within the connector 82). The connector 82 may comprise a port 83, such as a port configured and arranged to allow the introduction and / or removal of fluids into and from the delivery catheter 80. In some embodiments, a flushing fluid is introduced through one or more ports 83, as described below, to remove blood or other undesirable material from a location proximate to the optical assembly (e.g., from a location proximate to a location distal to the optical assembly, e.g., the optical assembly 115, described below). The port 83 may be disposed on a side of the connector 82 and may include a luer fitting and a cap and / or a valve. The shaft 81, connector 82, and port 83 may each comprise standard materials and have a construction similar to commercially available introducers, guide catheters, diagnostic catheters, mid-catheters, and microcatheters used in interventional procedures. The delivery catheter 80 may comprise a catheter configured to deliver the imaging probe 100 (via lumen 84) to a location in the brain, a location in the heart, and / or another location in the patient.

[0103] The imaging system 10 can include two or more delivery catheters 80, e.g., three or more delivery catheters 80. The multiple delivery catheters 80 can include at least a vascular introducer and other delivery catheters 80 that can be inserted into a patient from the vascular introducer after the vascular introducer is placed through the patient's skin. The two or more delivery catheters 80 can collectively include a set of inner diameters (ID) and outer diameters (OD), such that a first delivery catheter 80 slidably receives a second delivery catheter 80 (e.g., the second delivery catheter OD is equal to or smaller than the first delivery catheter ID), the second delivery catheter 80 slidably receives a third delivery catheter 80 (e.g., the third delivery catheter OD is equal to or smaller than the second delivery catheter ID), and so on. In these configurations, a first delivery catheter 80 can be advanced to a first anatomical location and a second delivery catheter 80 can be advanced through the first delivery catheter to a second anatomical location distal or otherwise distant (hereinafter "distal") relative to the first anatomical location, suitably using successively smaller diameter delivery catheters 80. The probe 100 can be advanced through and / or alongside one or more of the delivery catheters 80 (e.g., through the lumen of the smallest delivery catheter 80). In some embodiments, the delivery catheters 80 can be of similar construction and arrangement to similar components described in Applicant's co-pending U.S. patent application Ser. No. 15 / 751,570, entitled "Imaging System Includes Imaging Probe and Delivery Devices," filed Feb. 9, 2018.

[0104] The imaging probe 100 has an elongate body comprised of one or more elongate shafts and / or other tubes, herein an elongate shaft 120. The shaft 120 has a proximal end 1201, a distal end 1209, and a lumen 1205 extending therebetween. In some embodiments, the lumen 1205 includes multiple coaxial lumens within the one or more elongate shafts 120, e.g., one or more lumens are adjacent to one another to define a single lumen 1205. In some embodiments, at least a portion of the shaft 120 comprises a torque shaft. In some embodiments, a portion of the shaft 120 comprises a braided structure. The shaft 120 operatively surrounds a rotatable optical fiber, an optical core 110 (e.g., the optical core 110 is disposed within the lumen 1205), having a proximal end 1101 and a distal end 1109 (the proximal end 1101 is not shown, but is adjacent the proximal end 1201 of the shaft 120). The optical core 110 may comprise a dispersion shifted fiber, such as a depressurized cladding dispersion shifted fiber. The shaft 120 further comprises a distal portion 1208 including a transparent window 130 (e.g., a window relatively transparent to one or more frequencies of light transmitted through the optical core 110). The window 130 may comprise a full circumferential portion of the distal portion 1208 of the shaft 120. An optical assembly 115 is operably attached to the distal end 1109 of the optical core 110 (e.g., such that the optical assembly 115 rotates unitarily with the optical core 110). The optical assembly 115 is disposed within the window 130 of the shaft 120. A connector assembly 150 is disposed at the proximal end of the shaft 120. The connector assembly 150 operably attaches the imaging probe 100 to a rotating assembly 500, which is operably attached to the optical core 110. The rotation assembly 500 can be configured to rotate the optical core 110 within the shaft 120 as described herein.The connector assembly 150 may be of similar construction and arrangement to similar components described in Applicant's co-pending International PCT Patent Application Serial No. PCT / US2018 / 062766, entitled "Imaging System," filed November 28, 2018, and Applicant's co-pending U.S. Provisional Patent Application Serial No. 62 / 732,114, entitled "Imaging System with Optical Pathway," filed September 17, 2018. A second connector, a pullback connector 858, is disposed on the shaft 120. The connector 858 may be removably attached and / or adjustably disposed along the length of the shaft 120. The connector 858 may be disposed along the shaft 120 by an operator, such as proximal to the proximal end of the delivery catheter 80 (e.g., proximal to the connector 82 of the delivery catheter 80) after the imaging probe 100 is inserted into the patient via the delivery catheter 80. The shaft 120 may include a portion that accommodates slack in the shaft 120 between the connector assembly 150 and the location of the connector 858, a proximal portion of the shaft 120 (e.g., a proximal portion of the imaging probe 100), and a service loop 185.

[0105] The imaging probe 100 may include one or more visible markers along its length (e.g., along the shaft 120), with markers 131a-b shown (herein marker 131). The markers 131 may comprise markers selected from the group consisting of: radiopaque markers; ultrasound reflective markers; magnetic markers; ferrous; visible markers; and combinations of one or more of these. In some embodiments, the markers 131 comprise markers located in positions (e.g., within and / or at least near the distal portion 1208) that aid the operator of the imaging system 10 in performing a pullback procedure (e.g., a pullback procedure in which fluoroscopy and / or external ultrasound imaging is used). For example, the distal end 1209 of the shaft 120 may be located at a position distal to the proximal end of the implant after the pullback is completed (e.g., so that the imaging probe 100 may be safely advanced through the implant after the pullback).

[0106] In some embodiments, the imaging probe 100 includes a gel 180, which is a viscous damping fluid or other damping material disposed within the lumen 1205 of the shaft 120 and configured to reduce non-uniform rotation of the optical assembly 115. The gel 180 can surround at least a distal portion of the optical core 110. The gel 180 can further surround the optical assembly 115. The gel 180 can comprise a non-Newtonian fluid, for example a shear thinning fluid. In some embodiments, the gel 180 has a static viscosity of at least 500 centipoise and a shear viscosity that is less than the static viscosity. In these embodiments, the ratio of the static viscosity to the shear viscosity of the gel 180 can be between 1.2:1 and 100:1. The gel 180 may comprise a gel as described with reference to the applicant's co-pending U.S. patent application Ser. No. 15 / 566,041, entitled "Micro-Optic Probes for Neurology," filed on October 12, 2017, and the applicant's co-pending International PCT patent application Ser. No. PCT / US2018 / 062766, entitled "Imaging System," filed on November 28, 2018.

[0107] The imaging probe 100 can include a distal tip, distal tip 119. In some embodiments, the distal tip 119 comprises a spring tip or the like configured to improve the "navigability" of the imaging probe 100 (e.g., improve the "trackability" and / or "steerability" of the imaging probe 100), for example, within tortuous paths (e.g., within the blood vessels of the brain or heart, which have tortuous paths). In some embodiments, the tip 119 has a length between 5 mm and 100 mm (e.g., a spring having a length between 5 mm and 100 mm). Alternatively or additionally, the tip 119 can comprise a cap, plug, or other element configured to seal the distal opening of the window 130. In some embodiments, the tip 119 comprises a radiopaque marker configured to enhance visibility of the imaging probe 100 under x-ray or fluoroscopy. In some embodiments, the tip 119 includes a relatively short lumen guidewire pathway to allow for “quick exchange” translation of the imaging probe 100 .

[0108] In some embodiments, at least a distal portion of the imaging probe 100 (eg, the distal portion of the shaft 120 that surrounds the optical assembly 115) has an outer diameter of 0.020 inches or less, or 0.016 inches or less.

[0109] In some embodiments, the imaging probe 100 is configured and arranged for use in an intravascular neuro-procedure (e.g., a procedure for visualizing blood, vasculature, and other tissues adjacent to the brain and / or a procedure for visualizing a device placed temporarily or permanently adjacent to the brain). An imaging probe 100 configured for use in a neuro-procedure may have an overall length of at least 150 cm, for example, a length of about 300 cm.

[0110] Alternatively or additionally, the imaging probe 100 can be constructed and arranged for use in intravascular cardiac procedures (e.g., procedures for visualizing blood, vasculature, and other tissues proximate the heart and / or for visualizing devices placed temporarily or permanently proximate the heart). An imaging probe 100 configured for use in a cardiovascular procedure can have an overall length of at least 120 cm, such as an overall length of about 280 cm. In some embodiments, the imaging probe 100 has a length of at least 260 cm and / or up to 320 cm.

[0111] The rotating assembly 500 is operably attached to the connector 150 of the imaging probe 100. The rotating assembly 500 can include one or more rotational joints, optical connectors, rotational energy sources, and / or linkages configured to operably attach and rotate the optical core 110. The connector 150 can be configured and arranged to be removably attached to the rotating assembly 500 and to enable a rotational connection between the proximal end 1101 and a rotating fiber optic joint (such as a fiber optic rotary joint or FORJ). The rotating assembly 500 can be of similar construction and arrangement to similar components described in Applicant's co-pending International PCT Patent Application Serial No. PCT / US2018 / 062766, filed November 28, 2018, entitled "Imaging System," and Applicant's co-pending U.S. Provisional Patent Application Serial No. 62 / 732,114, filed September 17, 2018, entitled "Imaging System with Optical Pathway." The rotating assembly 500 can be configured to rotate the optical core 110 at a speed of at least 100 revolutions per second, e.g., at least 200 revolutions per second or 250 revolutions per second, or between 20 revolutions per second and 1000 revolutions per second. The rotating assembly 500 can comprise a source of rotational energy selected from the group consisting of a motor, a servo, a stepper motor (e.g., a stepper motor including a gear box), a linear actuator, a hollow core motor, and combinations thereof. In some embodiments, the rotating assembly 500 is configured to rotate the optical assembly 115 and the optical core 110 in unison.

[0112] The retraction assembly 800 is operably attached to the imaging probe 100 to retract the imaging probe 100 relative to the patient's access site. A retraction element 850 can be operably attached to the retraction assembly 800 and the imaging probe 100 to transmit a retraction force from the retraction assembly 800 to the imaging probe 100. The retraction element 850 can include a conduit 855 surrounding a linkage 856 slidably received therein. The retraction element 850 can include a connector 852 that operably attaches to the retraction assembly 800 such that the retraction assembly 800 can retract the linkage 856 relative to the conduit 855. In some embodiments, the conduit 855 includes a connector 857 that operably attaches to a reference point near the patient's access site, such as the connector 82 of the delivery catheter 80, to establish a reference for retraction of the imaging probe 100 relative to the patient. The connector 857 can be attached to a reference point, such as a patient introduction device, a surgical table, and / or other fixed or semi-fixed reference point. The linkage 856 can be releasably attached to a connector 858 of the imaging probe 100. The retraction assembly 800 retracts at least a portion of the imaging probe 100 (e.g., a portion of the imaging probe 100 distal from the attached connector 858) relative to the established reference by retracting the linkage 856 relative to the conduit 855 (e.g., retracting a portion of the linkage 856 out of a portion of the conduit 855 as shown). In some embodiments, the retraction assembly 800 is configured to retract at least a portion of the imaging probe 100 (e.g., at least a portion of the optical assembly 115 and shaft 120) at a rate between 5 mm / sec and 200 mm / sec, or between 5 mm / sec and 100 mm / sec, for example at a rate of about 60 mm / sec. Additionally or alternatively, the pullback procedure can be performed for a time period between 0.5 seconds and 25 seconds, such as about 20 seconds (eg, over a distance of 100 mm at 5 mm / sec).The service loop 185 of the imaging probe 100 can be positioned between the connector 857 and the rotating assembly 500 such that the imaging probe 100 can be retracted relative to the patient while the rotating assembly 500 remains stationary (e.g., attached to a portion of the operating table and / or console 50).

[0113] The retraction assembly 800 further comprises a motivation element configured to retract the linkage 856. In some embodiments, the motivation element comprises a linear actuator, a worm drive operably attached to a motor, a pulley system, and / or other linear force transmission mechanism. The linkage 856 can be operably attached to the motivation element via one or more linkages and / or connectors. The retraction assembly 800 can be of similar construction and arrangement to similar components described in Applicant's co-pending International PCT Patent Application Serial No. PCT / US2018 / 062766, entitled "IMAGING SYSTEM," filed November 28, 2018.

[0114] In some embodiments, the imaging system 10 includes a patient interface unit 200. The patient interface unit 200 may include a single housing that includes both the rotating assembly 500 and the retracting assembly 800. Alternatively or additionally, the patient interface unit 200 may include two or more housings, such as separate housings for each of the rotating assembly 500 and the retracting assembly 800. In some embodiments, the connector 150, the service loop 185, the retracting element 850, and the connector 852 are housed in a single housing configured to operably attach to both the rotating assembly 500 and the retracting assembly 800 (e.g., when the rotating assembly 500 and the retracting assembly 800 are housed within a single housing).

[0115] The console 50 comprises an imaging assembly 300, a user interface 55, a processor 52, and one or more algorithms 51. The imaging assembly 300 may be configured to provide light to the optical assembly 115 (e.g., via the optical core 110) and collect light from the optical assembly 115 (e.g., via the optical core 110). The imaging assembly 300 may include a light source 310. The light source 310 may comprise one or more light sources, such as one or more light sources configured to provide light of one or more wavelengths to the optical assembly 115 via the optical core 110. The light source 310 is configured to provide light to the optical assembly 115 (via the optical core 110) so that image data can be collected that comprises cross-sectional, longitudinal and / or volumetric information associated with the patient site or implanted device being imaged. The light source 310 can be configured to provide light such that the collected image data includes characteristics of tissue within the patient region being imaged, for example, to quantify, qualify, or otherwise provide information related to a patient disease or disorder present within the patient region being imaged. The light source 310 can be configured to deliver broadband light, having a central wavelength in the range of 350 nm to 2500 nm, in the range of 800 nm to 1700 nm, in the range of 1280 nm to 1310 nm, or in the range of about 1300 nm (e.g., light delivered in a swept range of 1250 nm to 1350 nm). The bandwidth of the light source 310 can be selected to achieve a desired resolution, which may vary depending on the needs of the intended use of the imaging system 10. In some embodiments, the bandwidth is about 5% to 15% of the central wavelength, which allows for a resolution between 20 μm and 5 μm. The light source 310 can be configured to provide light at a power level that meets ANSI Class 1 ("eye-safe") limits, although higher power levels can be employed. In some embodiments, the light source 310 emits light in the 1.3 μm band at a power level of approximately 20 mW. Increasing the central wavelength of the delivered light reduces light scattering in tissue but increases water absorption. The light source 310 can deliver light at wavelengths closer to 1300 nm to balance these two effects.The light source 310 can be configured to deliver shorter wavelength light (e.g., about 800 nm light) to traverse a patient region being imaged that contains a large amount of fluid. Alternatively or additionally, the light source 310 can be configured to deliver longer wavelength light (e.g., about 1700 nm light) to reduce high levels of scattering within the patient region being imaged. In some embodiments, the light source 310 comprises a tunable light source (e.g., the light source 310 emits a single wavelength that varies repeatedly over time) and / or a broadband light source. The light source 310 can comprise a single spatial mode light source or a multimode light source (e.g., a multimode light source with spatial filtering). The imaging assembly 300 can be similarly constructed and arranged with similar components described in applicant's co-pending U.S. Provisional Patent Application Serial No. 62 / 732,114, entitled "Imaging System with Optical Pathway," filed September 17, 2018.

[0116] The console 50 may comprise one or more algorithms, such as the illustrated algorithm 51, configured to adjust (e.g., automatically and / or semi-automatically adjust) one or more operating parameters of the imaging system 10, such as operating parameters of the console 50, the imaging probe 100 and / or the delivery catheter 80. The console 50 may further comprise a processing assembly, processor 52, configured to execute the algorithm 51 and / or perform any type of data processing, such as digital signal processing, as described below with reference to FIG. 4. Additionally or alternatively, the algorithm 51 may be configured to adjust an operating parameter of another device, such as the injector 20 or the implant delivery device 30, as described below. In some embodiments, the algorithm 51 is configured to adjust the operating parameter based on one or more sensor signals, such as sensor signals provided by a sensor-based functional element of the inventive concepts described herein. The algorithm 51 can be configured to adjust operating parameters selected from the group consisting of rotational parameters such as the rotational speed of the optical core 110 and / or the optical assembly 115, retraction parameters such as the retraction speed, distance, start position, end position and / or retraction start timing (e.g., when retraction is initiated) of the shaft 120 and / or the optical assembly 115, positional parameters such as the position of the optical assembly 115, line spacing parameters such as the number of lines per frame, image display parameters such as scaling of display size relative to vessel diameter, configuration parameters of the imaging probe 100, injectate 21 parameters such as a saline to contrast ratio configured to determine an appropriate refractive index, light source 310 parameters such as the power and / or frequency of the emitted light, and combinations of one or more of these.In some embodiments, the algorithm 51 is configured to adjust a retraction parameter, such as a parameter that triggers the initiation of a pullback, such as a pullback initiated based on a parameter selected from the group consisting of: flushing of the lumen (the lumen proximate the optical assembly 115 being sufficiently cleared of blood or other material that would interfere with imaging), receiving an indicator signal from the injector 20 (e.g., a signal indicating that sufficient flushing fluid has been delivered), a change in collected image data (e.g., a change in the image that correlates to adequate evacuation of blood from around the optical assembly 115 is detected based on the collected image data), and a combination of one or more of the above. In some embodiments, the algorithm 51 is configured to adjust a configuration parameter of the imaging system 10 associated with the imaging probe 100, such as when the algorithm 51 identifies the attached imaging probe 100 (e.g., automatically identifies via RF or other embedded ID) and adjusts a parameter of the imaging system 10, such as an arm path length parameter, a dispersion parameter, and / or other parameters as described above.

[0117] The imaging system 10 may include one or more interconnecting cables (bus 58 shown). The bus 58 may operatively connect the rotating assembly 500 to the console 50, the retracting assembly 800 to the console 50, and / or the assembly 500 to the retracting assembly 800 (e.g., by connecting the patient interface unit 200 to the console 50). The bus 58 may include one or more optical transmission fibers, electrical transmission cables, fluid conduits, and combinations of one or more of these. In some embodiments, the bus 58 includes at least an optical transmission fiber that optically couples the rotating assembly 500 to the imaging assembly 300 of the console 50. Additionally or alternatively, the bus 58 includes at least a power and / or data transmission cable that conveys power and / or synchronization information to the retracting assembly 800.

[0118] The user interface 55 may include an output 56 and an input 57. The output 56 may include one or more outputs selected from the group consisting of a screen, an indicator light, a tactile transducer such as a vibration transducer, a speaker, an output signal such as a wireless signal received by an external device, and combinations thereof. The input 57 may include an input selected from the group consisting of a button, two or more buttons, a touch screen, a mouse, an input signal such as a wireless signal received from an external device, and combinations thereof. In some embodiments, the output 56 and / or the input 57 are integrated into the patient interface unit 200 and / or into either or both of the rotation assembly 500 and the retraction assembly 800.

[0119] The second imaging device 15 may comprise an imaging device such as one or more imaging devices selected from the group consisting of an x-ray, a fluoroscope, such as a single or double plane fluoroscope, a CT scanner, an MRI, a PET scanner, an ultrasound imaging device, and combinations of one or more of the foregoing. In some embodiments, the second imaging device 15 comprises a device configured to perform rotational angiography.

[0120] The treatment device 16 may comprise an occlusion treatment or other treatment device selected from the group consisting of a balloon catheter configured and arranged to dilate a narrowing in a blood vessel, a drug eluting balloon, an aspiration catheter, a sonolysis device, an atherectomy device, a clot removal device such as a stent retriever device, a Trevo® stentriever, a Solitaire® stentriever, a Revive® stentriever, an Erick® stentriever, a Lazarus® stentriever, a stent retriever catheter, a microblade implant, an embolization system, a WEB® Embolization System, a Luna® Embolization System, a Medina® Embolization System, and one or more combinations thereof. In some embodiments, the imaging probe 100 is configured to collect data related to the treatment device 16 (e.g., position, orientation and / or other configuration data of the treatment device 16) after the treatment device 16 is inserted into the patient.

[0121] The injector 20 may comprise a power injector, a syringe pump, a peristaltic pump, or other fluid delivery device configured to inject contrast agents, such as radiopaque contrast agents, and / or other fluids. In some embodiments, the injector 20 is configured to deliver contrast agents and / or other fluids (e.g., contrast agents, saline, and / or dextran). In some embodiments, the injector 20 delivers the fluids in a flushing procedure as described below. In some embodiments, the injector 20 delivers the contrast agents or other fluids via a delivery catheter 80 having an ID between 5Fr and 9Fr, a delivery catheter 80 having an ID between 0.53 inches and 0.70 inches, or a delivery catheter 80 having an ID between 0.0165 inches and 0.027 inches. In some embodiments, the contrast agents or other fluids are delivered via a delivery catheter as small as 4Fr (e.g., for distal injection). In some embodiments, the injector 20 delivers contrast and / or other fluids through the lumen of one or more delivery catheters 80 while one or more smaller delivery catheters 80 are also present in the lumen. In some embodiments, the injector 20 is configured to deliver two dissimilar fluids simultaneously and / or sequentially, such as a first fluid delivered from a first reservoir and containing a first concentration of contrast and a second fluid delivered from a second reservoir and containing less or no contrast.

[0122] The injectate 21 may comprise a fluid selected from the group consisting of an optically transparent material, saline, a visualizable material, a contrast agent, dextran, an ultrasound reflective material, a magnetic material, and combinations thereof. The injectate 21 may include a contrast agent and saline. The injectate 21 may comprise at least 20% contrast agent. For example, a flushing procedure may be performed during collection of image data by delivering one or more fluids, the injectate 21 (e.g., as propelled by the injector 20 or other fluid delivery device), to remove blood or other somewhat opaque material (hereinafter, non-transparent material) in the vicinity of the optical assembly 115 (e.g., to remove non-transparent material between the optical assembly 115 and a delivery catheter and / or between the optical assembly 115 and a blood vessel wall) so that light directed from the optical assembly 115 reaches and reflects back to all tissues and other objects to be imaged. In these flushing embodiments, the injectate 21 may comprise an optically transparent material, such as saline. Injectate 21 may comprise one or more visualizeable materials, as described below.

[0123] Alternatively, or in addition to use in a flushing procedure, the injectate 21 may comprise a material configured to be visible to the second imaging device 15, such as where the injectate 21 comprises a contrast agent configured to be visible to the second imaging device 15 comprising a fluoroscope or other X-ray device, an ultrasound reflective material configured to be visible to the second imaging device 15 comprising an ultrasound imager, and / or a magnetic material configured to be visible to the second imaging device 15 comprising an MRI.

[0124] The implant 31 can comprise an implant (e.g., a temporary or chronic implant) that treats one or more of a vascular occlusion or an aneurysm. In some embodiments, the implant 31 comprises one or more implants selected from the group consisting of a flow diverter, a Pipeline® flow diverter, a Surpass® flow diverter, an embolic coil, a stent, a Wingspan® stent, a covered stent, an aneurysm treatment implant, and combinations of one or more of the foregoing.

[0125] The implant delivery device 30 may comprise a catheter or other tool used to deliver the implant 31, such as when the implant 31 comprises a self-expanding or balloon-expandable portion. In some embodiments, the imaging system 10 comprises an imaging probe 100, one or more implants 31 and / or one or more implant delivery devices 30. In some embodiments, the imaging probe 100 is configured to collect data related to the implant 31 and / or implant delivery device 30 (e.g., anatomical position, orientation and / or other configuration data of the implant 31 and / or implant delivery device 30) after the implant 31 and / or implant delivery device 30 are inserted into a patient.

[0126] In some embodiments, one or more system components, such as the console 50, the delivery catheter 80, the imaging probe 100, the patient interface unit 200, the rotation assembly 500, the retraction assembly 800, the treatment device 16, the injector 20, and / or the implant delivery device 30, further comprise one or more functional elements (herein "functional elements"), such as the illustrated functional elements 59, 89, 199, 299, 599, 899, 99a, 99b, and / or 99c, respectively. Each functional element may comprise at least two functional elements. Each functional element may comprise one or more elements selected from the group consisting of a sensor; a transducer; and combinations thereof. The functional element may comprise a sensor configured to generate a signal. The functional elements may comprise sensors selected from the group consisting of physiological sensors, pressure sensors, strain gauges, position sensors, GPS sensors, acceleration sensors, temperature sensors, magnetic sensors, chemical sensors, biochemical sensors, protein sensors, flow sensors such as ultrasonic flow sensors, gas detection sensors such as ultrasonic bubble detectors, sound sensors such as ultrasonic sensors, and combinations thereof. The sensors may comprise physiological sensors selected from the group consisting of pressure sensors such as blood pressure sensors, flow sensors such as blood gas sensors, blood flow sensors, temperature sensors such as blood or other tissue temperature sensors, and combinations thereof. The sensors may comprise position sensors configured to generate signals related to the geometry of the vascular pathway (e.g., the geometry of the vascular pathway in 2D or 3D). The sensors may comprise magnetic sensors. The sensors may comprise flow sensors. The system may further comprise algorithms configured to process the signals generated by the sensor-based functional elements. Each functional element may comprise one or more transducers.Each functional element can include one or more transducers selected from the group consisting of a heater, such as a heating element configured to provide sufficient heat to ablate tissue, a cooler, such as a cooling element configured to provide cryogenic energy to ablate tissue, a sound transducer, such as an ultrasound transducer, a vibration transducer, and combinations thereof.

[0127] In some embodiments, the imaging probe 100 includes a "bubble handling" mechanism, as illustrated, a fluid pressurizing element (FPE) 1500, such as for preventing or at least reducing the presence of air bubbles proximate the optical assembly 115, as described in detail herein. The FPE 1500 may be configured to generate a pressure differential within the volume of gel 180 and / or otherwise increase the pressure of one or more volumes of gel 180. The FPE 1500 may include a distal end disposed relatively close to a proximal end of the optical assembly 115. In some embodiments, the FPE 1500 is configured to increase the pressure and / or generate a pressure differential within a volume of gel 180 proximate to the optical assembly 115. Additionally or alternatively, the FPE 1500 may generate a flow of gel 180 (e.g., a flow of gel 180 containing one or more air bubbles that moves the air bubbles away from the optical assembly 115). The FPE 1500 may include a protrusion extending from the optical core 110 that increases the pressure of the gel 180 when the FPE 1500 rotates (via rotation of the optical core 110). Alternatively or additionally, the FPE 1500 may include a pump, pressurized reservoir, and / or other pressurized source (herein "pump") fluidly attached to one or more lumens (e.g., lumen 1205 of shaft 120) to increase the pressure of the gel 180 (e.g., intermittently, upon demand by system 10).

[0128] As shown in FIG. 1A, one or more gas bubbles B may be present in the gel 180. For example, as the optical core 110 and optical assembly 115 rotate within the gel 180, gas bubbles B may form, such as through cavitation and / or other gas bubble formation anomalies as described above. Additionally or alternatively, one or more gas bubbles B may be (already) present in the gel 180, such as a result of the manufacturing process of the imaging probe 100. In operation, gas bubbles B in proximity to the optical assembly 115 may cause undesirable imaging artifacts and / or other imaging problems. The FPE 1500 may be configured and arranged to prevent or at least reduce the formation of gas bubbles B, reduce the expansion of the one or more gas bubbles B, reduce the size of the one or more gas bubbles B, and / or move the one or more gas bubbles away from the optical assembly 115. In an initial start-up state (e.g., when the FPE 1500 has just begun to rotate), pressure in the gel 180 distal to the FPE 1500 increases, causing bubbles distal to the FPE 1500 to migrate distally and compress due to the increasing pressure, and bubbles proximal to the FPE 1500 initially migrate toward the FPE 1500 (as fluid moves to fill the space created by the compressed bubbles) but then stop migrating when an equilibrium pressure gradient is reached. In some embodiments, the FPE 1500 is configured to manipulate (e.g., propel) the gel 180 to create a region of high pressure HP surrounding the optical assembly 115 (e.g., the volume of the gel 180 proximate the optical assembly 115) and a region of low pressure LP proximate the FPE 1500 (e.g., the volume of the gel 180 proximate the optical assembly 115).

[0129] In some embodiments, one or more gas bubbles B may be trapped at a distal portion of the high pressure area HP, but the FPE 1500 is configured and arranged to manipulate the gel 180 at a proximal portion of the optical assembly 115 to prevent the gas bubbles B from being trapped at a proximal portion of the assembly 115 (e.g., to prevent any gas bubbles B trapped at the distal portion from migrating towards the optical assembly 115). Additionally or alternatively, the increased pressure of the high pressure area HP can cause a reduction in size of any existing gas bubbles B proximate the optical assembly 115 (e.g., compression of any gas bubbles B within the high pressure area HP) and / or the increased pressure can prevent new gas bubbles B from forming. In some embodiments, the high pressure area HP generated by the FPE 1500 has a pressure of at least 3.6 psi (e.g., at least about 0.25 atmospheres), e.g., a pressure of at least 5 psi, at least 10 psi, at least 15 psi, at least 20 psi, at least 30 psi, and / or at least 40 psi. In some embodiments, the FPE 1500 generates a pressure in the area HP of at least 75 psi, at least 100 psi, at least 125 psi, and / or at least 150 psi. In some embodiments, the high pressure area HP has a pressure at least 5 psi higher than the pressure in the low pressure area LP, e.g., at least 10 psi, at least 20 psi, and / or at least 30 psi higher. In some embodiments, each bubble B is compressed by a factor of two or three (i.e., 1 / 2 or 1 / 3 of its original size) under the high pressure conditions of the high pressure area HP.

[0130] In some embodiments, gel 180 comprises a low viscosity fluid, such as a shear thinning fluid, having a low starting viscosity such that air bubbles B are unlikely to form. For example, gel 180 can have a viscosity of 1000 centipoise or less. Additionally or alternatively, gel 180 can have a high surface tension, for example, a surface tension of at least 40 dynes / cm, such that air bubbles B are unlikely to form.

[0131] In some embodiments, the gel 180 is pressurized by the pump (intermittently pressurized to a pressure above atmospheric pressure) when the lumen 1205 is pressurized, e.g., via a pump fluidly connected to the lumen 1205 and located within the console 50 or patient interface unit 200 (e.g., the FPE 1500 includes this pump that is external but fluidly connected to the lumen 1205). In some embodiments, the gel 180 is pressurized by an external source, and the FPE 1500 is configured and arranged (e.g., when rotated) to generate a pressure differential within the gel 180 in addition to the pressure applied by the separate pump. Intermittent pressurization (e.g., via an external pump or via rotation of the FPE 1500) can provide a number of advantages, such as preventing a buildup of dissolved gases within the gel 180 due to constant applied pressure, as described herein.

[0132] In some embodiments, the FPE 1500 comprises a spiral protrusion extending radially from the optical core 110 configured to increase the pressure in the gel 180 and / or create a pressure differential within the gel 180 when the optical core 110 rotates, as described below with reference to FIG. 2. In some embodiments, the FPE 1500 comprises one or more radially extending protrusions from the optical core 110 configured to create a pressure differential within the gel 180 when the optical core 110 rotates, as described below with reference to FIG. 3. In some embodiments, the FPE 1500 comprises a pump, pressurized vessel, and / or other pressurized source (herein a “pump”), e.g., a fluid conduit fluidly attached at its proximal end to the pump and exiting into the lumen 1205 proximate the optical assembly 115, as described below with reference to FIG. 4.

[0133] In some embodiments, the FPE 1500 is configured to operate intermittently to intermittently create a pressure differential within the gel 180, such as to intermittently increase the pressure in the gel 180. For example, the FPE 1500 may include one or more radially extending protrusions from the optical core 110 configured to create a pressure differential within the gel 180 only when the optical core 110 is rotating, as described below with reference to FIG. 4A. In these embodiments, while the FPE 1500 is not operating (e.g., not rotating), the pressure in the gel 180 may normalize, such as to a pressure lower than the pressure of the high pressure region HP, while the FPE 1500 is operating (e.g., rotating). The intermittent pressurization may be implemented to prevent an increase in dissolved gas within the gel 180. In some embodiments, the FPE 1500 is configured to operate continuously for only limited periods of time, such as for discrete periods of 2 minutes or less at a time, e.g., 30 seconds or less, or 5 seconds or less (e.g., by intermittently pressurizing the gel 180 to prevent undesirable dissolved gases within the gel 180).

[0134] 2 and 2A, there is shown a schematic diagram of a distal portion of an imaging probe and delivery catheter, and a close-up view of components within circle M2, respectively, consistent with the concepts of the present invention. The imaging probe 100 and delivery catheter 80 may be similar in construction and arrangement to the imaging probe 100 and delivery catheter 80 described above with reference to FIGS. 1 and 1A. In the embodiment shown in FIGS. 2-2A, the fluid pressurizing mechanism, the illustrated FPE 1500s, comprises a helical protrusion extending radially from the optical core 110. In operation, as the optical core 110 rotates, the FPE 1500s rotates in unison, generating fluid flow adjacent the FPE 1500s and generating a pressure gradient within the gel 180 (e.g., across the FPE 1500s). Modeling of example fluid flow dynamics is described below with reference to FIGS. 2B-C.

[0135] In some embodiments, the FPE 1500s comprises a helical coil, such as a spring or other winding, affixed along a portion of the length of the optical core 110 (e.g., surrounding the core 110). The FPE 1500s can be attached to the optical core 110 via an adhesive or other adhesive substance. In some embodiments, the FPE 1500s is molded on and / or with the core 110, formed within the core 110 (e.g., via a material removal process), fused onto the core 110, and / or otherwise manufactured with or attached to the core 110. In some embodiments, the FPE 1500s comprises a material selected from the group consisting of metal; plastic; stainless steel; nickel-titanium alloy; nylon; polyetheretherketone (PEEK); polyimide; and combinations thereof. In some embodiments, the FPE 1500s can be formed directly on the optical core 110 using deposition and / or 3D printing techniques. In some embodiments, a selectively curable material is applied to the optical core 110 and cured in a helical pattern to form the FPE1500s. For example, a high strength UV curable adhesive can be applied to the surface of the optical core 110 and selectively cured using a rotating focused UV beam. In some embodiments, the FPE1500s can include a material selected to minimize deformation of the FPE1500s while a pressure gradient is applied. For example, during rotation, a pressure gradient may develop across the length of the FPE1500s, such that a shorter FPE1500s would require a harder material to prevent deformation than a longer FPE1500s configured to generate the same pressure gradient.

[0136] The FPE 1500s has a radial height, H1, which is the distance from the surface of the optical core 110 to the outer edge of the FPE 1500s. The optical core 110 has a diameter D1. The lumen 1205 of the shaft 120 has an inner diameter D2. In some embodiments, the diameters D1 and D2 vary along the length of the probe 100, and the following dimensions are for a segment of the probe 100, such as the distal segment (e.g., the proximal and proximal segments of the optical assembly 115) shown in FIG. 2A. The probe 100 can have a clearance C1 between the FPE 1500s (e.g., the outer diameter of the FPE 1500s) and the inner wall of the shaft 120. The clearance C1 is related to both the difference between the diameters D1 and D2 and the height H1 of the FPE 1500s, such that C1 is equal to half the difference between D1 and D2 minus H1. In some embodiments, the clearance C1 has a clearance of 100 μm or less, 75 μm or less, for example, between 10 μm and 75 μm. In some embodiments, the height H1 has a height that is 5% to 95% of half the difference between D1 and D2 (e.g., a height H1 that occupies at least 5% and / or 95% or less of the space between the outer surface of the core 110 and the inner wall of the shaft 120). In some embodiments, the optimal height H1 depends on factors such as the damping fluid viscosity (e.g., gel 180 viscosity), the desired rotational speed of the optical core 110, the desired pressure gradient, and / or the clearance between the FPE 1500s and the inner wall of the shaft 120 (e.g., tighter clearance creates higher pressure). In some embodiments, the coil profile of the FPE 1500s has a width W1 as shown. The width W1 can have a width of 1% to 95% of the diameter D1. The FPE 1500s can also have a pitch P1 as shown. The pitch P1 can have a gap between adjacent coils that is 0.5 to 20 times the diameter D1. In some embodiments, adjacent coils do not contact each other. In some embodiments, the pitch P1 is uniform along the length of the FPE 1500s.In some embodiments, the pitch P1 can have a pitch between 0.2 mm and 1.2 mm, such as a pitch of about 0.5 mm or 1 mm. In some embodiments, the length and / or pitch P1 of the FPE 1500s can be selected to achieve a desired pressure generated when the optical core 110 rotates.

[0137] In some embodiments, the gel 180 comprises a high viscosity, shear thinning fluid, as described with reference to FIG. 1 above. In some embodiments, the maximum functional clearance C1 (e.g., the maximum allowable clearance C1 at which rotation of the FPE 1500s generates sufficient fluid pressurization in the lumen 1205) is proportional to the viscosity of the gel 180. For example, the more viscous the gel 180, the greater the maximum clearance C1. In some embodiments, the clearance C1 is proportional to the pressure differential that can be generated in the gel 180 by rotating the FPE 1500s, as described herein. For example, the smaller the clearance C1, the greater the pressure differential that can be generated. In some embodiments, the clearance C1 and height H1 are minimized to limit turbulence, recirculation, and / or other unwanted fluid flow proximate the optical core 110. In some embodiments, the gel 180 comprises a Newtonian fluid (non-shear thinning). The dimensions C 1 , H 1 , D 1 , and D 2 can be optimized for different properties of the gel 180 .

[0138] In some embodiments, the FPE1500s comprises a coating (not shown). The coating can comprise a sheath, such as heat shrink tubing, and / or a painted or sprayed coating. The coating can be configured to improve coupling of the FPE1500s to the optical core 110 and / or to control the dimensions of the FPE1500s (e.g., to hold the FPE1500s securely to the optical core 110, to limit undesirable variations in height H1). Additionally or alternatively, the coating can be configured to modify surface characteristics of either or both of the optical core 110 and the FPE1500s. In some embodiments, the coating has a thickness that does not significantly affect the fluid propulsion and / or other fluid pressurization (herein "fluid pressurization") performance of the FPE1500s. Alternatively or additionally, the FPE1500s can be configured and positioned such that dimensions C1, H1, and D1 are optimized after application of the coating.

[0139] In some embodiments, the pressurization of the gel 180 within the lumen 1205 caused by rotation of the FPE 1500s exerts a functional torsional shear force on the inner wall of the lumen 1205. The shaft 120 can have a torsional resistance greater than the functional torsional shear force exerted by the gel 180. In some embodiments, the gel 180 exerts a torque of about 0.004 N·cm and the shaft 120 has a torsional resistance of at least 0.01 N·cm, e.g., 0.03 N·cm. Additionally or alternatively, the FPE 1500s can exert a "roll-up" stress on the optical core 110 as the optical core 110 is rotated, driving the FPE 1500s within the gel 180. The optical core 110 can be constructed and arranged such that it is not adversely affected (e.g., does not break or otherwise fail) by shear stresses induced by rotation of the core 110 and FPE 1500s within the gel 180, as well as shear stresses induced by pullback motion within the gel 180. In some embodiments, the additional roll-up stresses on the optical core 110 caused by the FPE 1500s function as a NURD reduction mechanism, similar to the NURD reduction caused by the gel 180, as described in Applicant's co-pending International PCT Patent Application Serial No. PCT / US2018 / 062766, entitled "Imaging System," filed November 28, 2018.

[0140] 2B and 2C, a schematic diagram of a distal portion of an imaging probe showing fluid flow patterns and a fluid flow simulation, respectively, consistent with the concepts of the present invention are shown. The movement of gel 180 is indicated by fluid flow arrows FF in FIG. 2B and path FP in FIG. 2C. P and F.P. D2B. The optical core 110 and FPE 1500s are depicted as rotating while the top end of the FPE 1500s rotates into the page. Along with the axial movement shown, the fluid flow also includes a rotational component, as shown in FIG. 2C. The distal tip 1209 and / or at least a distal portion of the shaft 120 can be sealed, such as when the distal tip 119 includes a cap or plug configured as a sealing element, plug 1209a shown in FIG. 2B. Rotating the FPE 1500s as shown causes fluid proximate to the optical core 110 to flow distally toward the high pressure region HP. When the pressure in the high pressure region HP increases to match the pressure of the distal fluid flow, a closed loop recirculation pattern emerges, as shown. Fluid propelled distally by the FPE 1500s encounters the pressure in the high pressure area HP and redirects proximally along the surface of the lumen 1205 (e.g., along the path of least resistance). This fluid flow pattern creates a "dead head" pressure profile (e.g., no net fluid flow) and maintains a pressure gradient along the FPE1500s from the low pressure area LP to the high pressure area HP. As shown in Figure 2C, the fluid path FP D illustrates the flow of fluid proximal to the optical core 110 and toward the distal high pressure region HP. P illustrates fluid flow adjacent the surface of lumen 1205 and proximally toward low pressure area LP.

[0141] 3A and 3B, there are shown schematic diagrams of the distal portions of two imaging probes including fluid propulsion elements consistent with the concepts of the present invention. FIG. 3A shows a rapid exchange distal tip 119. RX FIG. 3B illustrates a distal portion of the imaging probe 100a, including the spring tip 119. S3A and 3B depict a distal portion of imaging probe 100b including a lens assembly 1151. Imaging probes 100a and 100b of FIGS. 3A and 3B may include similar components and may be similarly constructed and arranged as imaging probe 100 of FIGS. 1 and 1A described herein. Optical assembly 115 may include a lens assembly, assembly 1151, optically and physically coupled to a distal end of optical core 110. Lens assembly 1151 may include a GRIN lens including a beveled distal end. The beveled distal end of lens assembly 1151 may include a total internal reflection surface. An elongated tube, tube 1154, surrounds at least a distal portion of optical core 110, lens assembly 1151, and sealing element, plug 1153 (e.g., a sealing element similar to plug 1209a of FIG. 2B). Tube 1154 may include a heat shrink material. Tube 1154 may include PET. At least a portion of the tube 1154 can be glued or otherwise secured to at least a portion of the lens assembly 1151, the optical core 110, and / or the plug 1153. The plug 1153 is configured to prevent and / or limit the escape of the gel 180 into a cavity (space 1152 as shown) created between the lens assembly 1151 and the plug 1153. The space 1152 can be filled with air and / or one or more other fluids. The fluid in the space 1152 can be configured to provide desired optical properties between the lens assembly 1151 and the fluid (e.g., provide a glass-air interface). The optical core 110 can include a support element 1102. The support element 1102 can include a torque wire disposed proximal to the optical assembly 115. The support element 1102 can be configured to reinforce a distal portion of the optical core 110, such as to provide rotational reinforcement to the optical core 110.

[0142] In some embodiments, the FPE 1500 may include, as shown in FIGS. 3A and 3B, S1 and 1500 S2 Distal FPE1500 S1may be configured to generate a pressure gradient across the optical assembly 115, as described herein. S2 The gel 180 is proximal (e.g., FPE1500 S2 and / or FPE1500 S1 to prevent cavitation proximal to the S1 To prevent air bubble formation proximal to the S1 The FPE1500 can be configured to "prime" the S2 may be located proximate the proximal end of the gel 180 (eg, proximate the location within the shaft 120 where the gel 180 is inserted from the distal end of the shaft 120 during manufacture).

[0143] 4 and 4A, there is shown a schematic diagram of a distal portion of an imaging probe and delivery catheter, and a close-up view of the components within circle M3, respectively, consistent with the concepts of the present invention. The imaging probe 100 of FIG. 4 and FIG. 4A may include similar components and be similarly constructed and arranged as the imaging probe 100 of FIG. 1 described herein. The imaging probe 100 of FIG. 4 and FIG. 4A includes a pressure element, FPE1500, having a propeller-like structure. P Includes: FPE1500 P The FPE 1500 may include one or more radial protrusions 1501 extending from the optical core 110. The protrusions 1501 have a profile configured to propel the fluid when the optical core 110 rotates, similar to a propeller blade. P can be configured to create a pressure gradient within the gel 180, as described above.

[0144] 5 and 5A, there is shown a schematic diagram of a distal portion of an imaging probe and delivery catheter, and a close-up of the components within circle M4, respectively, consistent with the concepts of the present invention. The imaging probe 100 of FIGS. 5 and 5A is comprised of similar components and may be of similar construction and arrangement as the imaging probe 100 of FIG. 1, as described herein. The imaging probe 100 of FIGS. 5 and 5A is coupled to a pump, the FPE1500. PS The pressure element comprises: PS The FPE 1500 can include a fluid lumen 1502 having an exit port 1503 that exits into a lumen 1205 proximal to the optical assembly 115. The lumen 1205 can be fluidly connected to a pump, not shown, such as the pump in the console 50 of FIG. 1. The pump can be used to fluidly pump the FPE 1500 before, during, and / or after an imaging procedure. PS The FPE1500 can be configured to apply pressure to the gel 180 via the PS The FPE 1500 may further include a fluid restricting element, a valve 1504. The valve 1504 is shown disposed proximal to the exit port 1503 within the lumen 1205. The valve 1504 may be disposed in the FPE 1500. PS The FPE 1500 may be configured to restrict the flow of fluid (e.g., gel 180) proximally within the lumen 1205 such that the valve 1504 can generate increased pressure in the gel 180 at a location distal to the valve 1504. The valve 1504 may be configured to restrict the passage of the gel 180 (e.g., due to the viscosity and / or molecular size of the gel 180) while allowing the passage of air and / or other gases (e.g., air bubbles B described herein). PS can be configured to generate a pressure gradient within the gel 180, as described herein with reference to Figures 1 and 1A.

[0145] 6A, 6B, and 6C, there are shown cross-sectional views of a distal portion of an optical probe consistent with the concepts of the present invention. The imaging probe 100 may be similar in construction and arrangement to the imaging probe 100 described above with reference to FIGS. 1 and 1A. In some embodiments, the optical core 110 is configured to be retracted and advanced within the shaft 120, as shown in FIGS. 6A-C. The optical core 110 may be retracted (here as shown in FIG. 1) via a linkage 856 operably attached to a proximal portion of the optical core 110. A fluid pressurizing element optically coupled to the optical core 110 may be a spring-type element, FPE 1500, as described herein with reference to FIGS. 2-3B. S It can include: FPE1500 S may be configured to generate a pressure gradient from a low pressure area LP to a high pressure area HP within the gel 180, as described herein. In some embodiments, when the optical core 110 is retracted within the shaft 120, the retraction may result in voids (e.g., one or more air bubbles formed due to the pressure drop caused by the retraction of the optical core 110) within the gel 180. S The FPE 1500 can be configured to minimize the creation of these voids by creating a pressure gradient within the gel 180 while the optical core 110 is rotating and retracting. S can be configured to generate a motive force configured to drive at least the distal end of the optical core 110 longitudinally (e.g., proximally and / or distally) within the lumen 1205 of the shaft 120.

[0146] FPE1500 S can be configured to generate both a motive force and a pressure gradient within the gel 180, giving rise to one or more resulting scenarios, as shown in Figures 6A-C. In Figure 6A, the optical core 110 (FPE 1500 S When rotated in a first direction (such that the gel 180 is urged distally), a pulling force F acts on the optical core 110. R, which creates a pressure gradient from the low pressure area LP to the high pressure area HP. The optical core 110 is held in place by a retention force F, such as the force exerted by the retraction assembly 800, as described above with reference to FIG. H In this state, the optical core 110 does not move longitudinally (e.g., proximally and / or distally) within the shaft 120.

[0147] As shown in FIG. 6B, the retention force F H When is removed, the force F R The force F acts to retract at least a distal portion of the optical core 110 into the shaft 120. In some embodiments, the retraction assembly 800 also applies a retraction force to the optical core 110. R can be configured to assist in the retraction of the optic core 110 within the shaft 120, thereby limiting stress on the optic core 110 during application of a retraction force from the proximal portion.

[0148] In some embodiments, as shown in FIG. 6C, the optical core 110 (and FPE 1500 S ) is FPE1500 S drives the gel 180 in the proximal direction, exerting a forward force F on the optical core 110. A In some embodiments, the retraction assembly 800 can apply an advancing force to the proximal portion of the optical core 110. The force F A applies a force F while the retraction assembly 800 applies a force against the proximal portion. A It can be configured to limit and / or prevent kinking of the optical core 110 within the shaft 120 by applying a (pulling force) to a distal portion of the optical core 110 .

[0149] 7, there is shown a cross-sectional view of a segment of an imaging probe having a shaft of multi-component construction consistent with the concepts of the present invention. The imaging probe 100 of the concepts of the present invention can include a shaft having multiple components, such as the components of shaft 120 shown in FIG. 7. The shaft 120 can include at least a first (proximal) portion of a tube 121 fixedly attached to a second (distal) portion of a window 130 via a joint 125. The tube 121 can include an elongated hollow member, such as a hypotube (e.g., a metal tube that can include one or more engineered features along its length). In some embodiments, the tube 121 includes a hypotube that includes a helical cut along at least a portion of its length. In some embodiments, the tube 121 includes a nickel titanium alloy (e.g., Nitinol). In some embodiments, the tube 121 includes a plastic material, such as polyimide or PEEK. In some embodiments, the window 130 includes a transparent elongated hollow member, such as described above with reference to FIG. 1.

[0150] The joint 125 can comprise at least a distal portion of the tube 121 and at least a proximal portion of the window 130. The distal portion of the tube 121 can comprise a tapered portion, a taper 1211. The taper 1211 can be configured such that an outer diameter of the tube 121 decreases from a proximal end of the taper 1211 toward a distal end of the taper 1211. The tube 121 comprises a lumen 1215 therethrough. An elongated segment, tube 123, is partially inserted into the lumen 1215 of the tube 121. The tube 123 can have an outer diameter approximately equal to a diameter of the lumen 1215. In some embodiments, tube 123 has an outer diameter slightly larger than the diameter of lumen 1215 (e.g., so that tube 123 can be press-fitted into lumen 1215), or tube 123 has a diameter the same as or slightly smaller than the diameter of lumen 1215 (e.g., to provide space for adhesive between tube 125 and tube 121). Tube 123 includes a lumen 1235 therein. In some embodiments, lumen 1235 has a diameter larger than the outer diameter of optical core 110 (e.g., so that optical core 110 can be slidably disposed therein). Additionally or alternatively, lumen 1235 can be configured to accommodate FPE 1500. S cannot translate proximally beyond the tube 123 (e.g., FPE1500 S The proximal translation of FPE1500 S contacts the end of the tube 123, and the FPE1500 S (to prevent 1235 from entering the lumen), FPE1500 S The inner diameter of the tube 123 may be smaller than the outer diameter of the tube 123 (eg, the tube 123 may constitute the inner diameter).

[0151] The joint 125 can further include an overtube 122 configured to surround at least a distal portion of the tube 121 and at least a portion of the tube 123 (e.g., at least a portion of the tube 123 extending distally from the lumen 1215). The overtube 122 can comprise a “heat shrink” material (e.g., a material configured to shrink when heat is applied). In these embodiments, the overtube 122 can have a first diameter (e.g., a pre-shrunk diameter) that is equal to or greater than an outer diameter of the tube 121 such that the tube 121 is slidably received within the overtube 122. After the overtube 122 is positioned relative to the tubes 121, 123, heat can be applied such that the overtube 122 shrinks and conforms to the outer profile of the tubes 121, 123. Additionally or alternatively, the overtube 122 can comprise a resilient material. In some embodiments, the overtube 122 can have an elastic material and an inner diameter equal to or less than the outer diameter of the tube 123. In these embodiments, the overtube 122 can be positioned relative to the tubes 121, 123 by stretching the overtube 122 to slidably receive the tubes 121, 123, and then contracting to conform to the outer profile of the tubes 121, 123. In some embodiments, the overtube 122 can be "rolled" over the tubes 121, 123, such that the overtube 122 stretches and deforms as it is rolled over the tubes 121, 123. The overtube 122 can comprise PET.

[0152] The proximal portion of the window 130 can include an inwardly directed radial protrusion 1302. The radial protrusion 1302 can have an inner diameter configured and arranged to match the outer diameter of the tube 123, 122 (e.g., the outer diameter of the tube 122 compressed relative to the tube 123). In some embodiments, the window 130 does not include a radial protrusion 1302, and the inner diameter of the window 130 is configured and arranged to match the outer diameter of the tube 123, 122. In some embodiments, the proximal portion of the window 130 slidably receives a distal portion of the tube 122, 123. The proximal portion of the window 130 can further slidably receive at least a distal portion of the taper 1211 of the tube 121. The window 130 can be fixedly attached to the tubes 121, 122, and / or 123 via compression and / or adhesive. In some embodiments, the exterior surface of overtube 122 can be prepared (e.g., mechanically or chemically prepared) for bonding to window 130, for example, via a chemical primer. In some embodiments, the proximal end of window 130 is "shrunk" onto tubes 121, 122, and / or 123 to provide a compression fit. In some embodiments, window 130 comprises a material configured to shrink when under tension (e.g., when window 130 is intentionally or unintentionally pulled away from tube 121), such that window 130 is compressed onto tubes 121, 122, and / or 123 and strengthens joint 125 when under tension. In these embodiments, tubes 121, 122, and / or 123 can have a lower elastic modulus than window 130, such that window 130 compresses more under equal tension than one or more of tubes 121, 122, and / or 123.

[0153] In some embodiments, the joint 125 has a maximum outer diameter of 0.02 inches or less, e.g., 0.0175 inches or less, e.g., 0.0155 inches or less. In some embodiments, the joint 125 has a tensile strength of at least 2 N, e.g., at least 2.6 N, e.g., at least 5.5 N, e.g., at least 6 N. In some embodiments, the distal portion of the imaging probe 100 (including the joint 125 and at least a distal segment of the tube 121, e.g., the distal 30 cm of the imaging probe 100) has a minimum bend radius of 5 mm or less, e.g., 4 mm or less, 3 mm or less, or 2.5 mm or less.

[0154] In some embodiments, the optical core 110 can comprise two or more layers (e.g., two or more concentric layers), such as a core 1105, which can be surrounded by a cladding 1106, which can be one or more layers of cladding.

[0155] 8, there is shown a cross-sectional view of a portion of an imaging probe including a bi-directional fluid propulsion element consistent with the concepts of the present invention. The imaging probe 100 of FIG. 8 includes similar components and may be similarly constructed and arranged as the imaging probe 100 of FIG. 1 described herein. The imaging probe 100 of FIG. 8 includes two fluid propulsion elements, FPE1500. F and 1500 R In some embodiments, the FPE1500 F As shown in Figure 8, FPE1500 R The FPE1500 can be placed proximal to the F 1500 when the optical core 110 is rotated in a first direction as described herein. R The FPE1500 can be configured to propel the FPE1500 distally toward the R When the optical core 110 is also rotated in the first direction, the gel 180 is rotated to the FPE 1500. F (e.g., FPE1500 F and 1500R (When the two are rotated in the same direction, they propel the gel 180 in opposite directions). In this way, the FPE 1500 F and 1500 R The FPE 1500 may be configured to maintain the gel 180 between one another (e.g., to create a confined region of pressurized gel 180 between the two elements). In some embodiments, as the optical core 110 advances and / or retracts within the shaft 120, the FPE 1500 F and 1500 R The FPEs 1500 and 1600 may be configured to move the gel 180 in a translating fashion along with the optical core 110 (e.g., as these FPEs move along with the optical core 110). F and 1500 R In some embodiments, the rotation of the optical core 110 is reversed to form the FPE 1500. F and 1500 R The gel 180 can be at least partially retracted from the area between the.

[0156] 9A-9, there are shown perspective views of four steps of a process for fabricating a fluid propulsion element consistent with the concepts of the present invention. FIG. 9A shows a tube 1510 (e.g., a polyimide tube) surrounding a mandrel 1520. A helical channel is cut (e.g., laser cut) into the tube 1510 (e.g., after the mandrel 1520 is inserted into the tube 1510). In FIG. 9B, the mandrel 1520 is rotated 180° and a second helical channel is cut to separate the tube 1510 into a first fluid propulsion element FPE1 and a second fluid propulsion element FPE2 (e.g., two similar or dissimilar FPEs 1500s), each of which surrounds the mandrel 1520. In FIG. 9C, the FPE2 has been removed from the mandrel 1520, e.g., the FPE2 has been peeled from the mandrel 1520. In FIG. 9D, FPE1 has also been removed from the mandrel 1520 (e.g., peeled or slid off the mandrel 1520). The illustrated process provides two fluid propulsion elements of the inventive concept, such as for use in a single optical probe 100 comprising two FPEs 1500s and / or for use in two optical probes 100, each comprising a single FPE 1500. In this process, each of FPE1 and FPE2 can have matching dimensions, for example, where the coil spacing is equal to the coil width of each FPE. In some embodiments, three or more slits can be made in the tube 1510 to produce three or more FPEs 1500s.

[0157] The above-described embodiments should be understood to serve as examples only, and further embodiments are envisioned. Any feature described herein in relation to any one embodiment may be used alone or in combination with other features described, and may also be used in combination with one or more features of any other embodiment, or with any other combination of embodiments. Moreover, equivalents and modifications not described above may be employed without departing from the scope of the inventive concept as defined in the appended claims.

Claims

1. Imaging probe and It includes an imaging assembly, The imaging probe is A long, slender shaft having a proximal end, a distal end, and a lumen extending between the proximal end and the distal end, A rotatable optical core having a proximal end and a distal end, wherein at least a portion of the rotatable optical core is located within the lumen of the elongated shaft, An optical assembly positioned close to the distal end of the rotatable optical core and configured to irradiate tissue with light and collect reflected light from the tissue, A damping fluid is disposed between the elongated shaft and the rotatable optical core, and is configured to reduce the uneven rotation of the optical assembly. The system comprises a fluid pressurizing element having a spiral projection extending radially from the rotatable optical core, configured to increase the pressure of the damping fluid when the rotatable optical core rotates and to reduce the presence of bubbles near the optical assembly. The aforementioned imaging assembly is It is configured and positioned to be optically coupled with the imaging probe, and is configured to emit light to the imaging probe and receive the reflected light collected by the optical assembly, The damping fluid includes a shear-reducing fluid. A patient imaging system.

2. The fluid pressurizing element is configured to intermittently increase the pressure of the damping fluid. The system according to claim 1.

3. The fluid pressurizing element is configured to increase the pressure of the damping fluid for a discrete time of 5 seconds or less. The system according to claim 2.

4. The fluid pressurizing element is configured to generate a pressure of at least 3.6 psi of the damping fluid. The system according to claim 1.

5. The spiral projection has a pitch between 0.2 mm and 1.2 mm. The system according to claim 1.

6. The fluid pressurizing element comprises a first fluid pressurizing element and a second fluid pressurizing element, The second fluid pressurizing element is positioned proximal to the first fluid pressurizing element. The system according to claim 1.

7. The second fluid pressurizing element is configured such that when it rotates, it prevents the damping fluid from moving from the distal side to the proximal side of the second fluid pressurizing element. The system according to claim 6.

8. The fluid pressurizing element is further configured to generate a driving force, The aforementioned driving force is configured to translate the rotatable optical core. The system according to claim 1.

9. The fluid pressurizing element is configured to advance the rotatable optical core when rotated in a first direction, and to retract the rotatable optical core when rotated in a second direction opposite to the first direction. The system according to claim 8.

10. The fluid pressurizing element is adhesively attached to the rotatable optical core. The system according to claim 1.

11. The fluid pressurizing element is formed within the rotatable optical core, The system according to claim 1.

12. The system is formed on the rotatable optical core by vapor deposition and / or three-dimensional (3D) printing, The system according to claim 11.

13. The damping fluid has a static viscosity of at least 500 centipoise. The system according to claim 1.

14. The damping fluid has a ratio of static viscosity to shear viscosity of at least 1.2:

1. The system according to claim 13.

15. The damping fluid comprises a fluid having high surface tension configured to reduce the formation of bubbles, The system according to claim 1.

16. The damping fluid comprises a fluid having a surface tension of at least 40 dynes / cm. The system according to claim 15.

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