Medical devices, sensors for medical devices, and related methods

Abstract

Medical devices incorporating sensors, systems using such medical devices, methods of manufacture, and methods of use are provided. In one non-limiting example, such medical devices may include intraluminal devices such as guidewires and / or catheters that include various sensors for detecting, imaging, and / or measuring one or more physiological parameters. In one embodiment, the guidewire may include an elongate element and at least one sensor that includes a piezoelectric material having a curing temperature of approximately 100° C. or less or an acoustic impedance of approximately 14 MRayl or less.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 328,842, entitled MEDICAL DEVICES, SENSORS FOR MEDICAL DEVICES AND METHODS OF MANUFACTURING, which is incorporated herein by reference in its entirety. [Background technology]

[0002]

[0002] The present disclosure relates generally to medical devices incorporating sensors. In one non-limiting example, such medical devices may include intraluminal devices, such as guidewires and catheters, that include various sensors for detecting, imaging, and / or measuring one or more physiological parameters.

[0003]

[0003] Guidewire devices are often used to guide or direct catheters or other interventional devices to a target anatomical site within a patient's body. Typically, the guidewire is threaded through the patient's vascular system to reach the target site, which may be, for example, at or near the patient's heart or brain. Radiographic imaging is usually utilized to help navigate the guidewire to the target site. Guidewires are available in a variety of outer diameter sizes. For example, commonly utilized sizes include, for example, diameters of 0.0254, 0.03556, 0.04064, 0.04572, 0.06096, and 0.0889 cm (0.010, 0.014, 0.016, 0.018, 0.024, and 0.035 inches), although they may be smaller or larger in diameter.

[0004]

[0004] Often, a guidewire is placed within the body during an interventional procedure, where it may be used to guide multiple catheters or other interventional devices to a target anatomical site. Once in place, the catheters may be used to aspirate a blood clot or other obstruction, or to deliver drugs, stents, embolic devices, radiopaque dyes, or other devices or substances to treat the patient.

[0005]

[0005] These types of interventional devices may include sensors located at the distal end to provide additional functionality to the device. For example, intravascular ultrasound (IVUS) is an imaging technique that utilizes a catheter with an ultrasound imaging sensor attached to its distal end. Ultrasound is utilized to image within the target vasculature, typically the coronary arteries. In another example, the sensor may include a physiological sensor configured to measure, for example, pressure, temperature, or flow within the blood vessel. Summary of the Invention [Problem to be solved by the invention]

[0006]

[0006] There are several challenges associated with using sensors with intraluminal devices. For example, such interventional devices involved must function in very limited spaces given the stringent dimensional constraints involved. Moreover, integrating sensors with interventional devices in a manner that maintains effective functionality can be difficult.

[0007]

[0007] There is a continuing need for improved medical devices that effectively integrate sensors and help provide data in a more efficient manner and / or provide data in an actionable manner that was not previously obtainable. [Means for solving the problem]

[0008]

[0008] Medical devices incorporating sensors, systems employing such medical devices, methods of manufacture, and methods of use are provided. In one non-limiting example, such medical devices may include intraluminal devices, such as guidewires and / or catheters, that include various sensors for detecting, imaging, and / or measuring one or more physiological parameters.

[0009] In one embodiment, a guidewire is provided that includes an elongate element and at least one sensor. The at least one sensor includes a piezoelectric material having a cure temperature of about 100° C. or less (and optionally at least about 50° C., 60° C., 70° C., or 80° C.) and an acoustic impedance of about 14 MRayl or less (and optionally at least about 1.5 MRayl, 3 MRayl, 5 MRayl, 7.5 MRayl, or 10 MRayl).

[0010] In one embodiment, the at least one sensor includes a plurality of sensors circumferentially disposed about a portion of the elongate element.

[0011] In one embodiment, the plurality of sensors includes at least eight sensors.

[0011]

[0012] In one embodiment, the multiple sensors exhibit a pitch (ie, the circumferential distance from one sensor to the next) of approximately 125 microns (μm) or less.

[0013] In one embodiment, the multiple sensors exhibit a pitch of approximately 62.5 microns (μm) or less.

[0012]

[0014] In one embodiment, the multiple sensors exhibit a pitch of approximately 31 microns (μm) or less.

[0015] In one embodiment, the elongate element comprises at least one of a core wire or a hypotube, and the at least one sensor is formed directly on the core wire or hypotube.

[0013]

[0016] In one embodiment, the at least one sensor is formed on a polymeric film.

[0017] In one embodiment, the polymeric film comprises a polyimide.

[0014]

[0018] In one embodiment, the polymeric film is disposed on the core wire or hypotube.

[0019] In another embodiment, a method is provided that includes providing an elongate element and positioning at least one sensor along a portion of the elongate body, the method including forming the at least one sensor of a piezoelectric material at a temperature of approximately 100° C. or less and an acoustic impedance of approximately 14 MRayl or less.

[0015]

[0020] In one embodiment, the method further includes positioning sensors within a blood vessel and emitting ultrasound from the at least one sensor to determine a characteristic of the blood vessel.

[0016]

[0021] In one embodiment, the method further comprises detecting reflections of the emitted ultrasound waves to determine a characteristic of the blood vessel.

[0022] In one embodiment, the blood vessel characteristics include the size of the lumen of the blood vessel.

[0017]

[0023] In one embodiment, forming the at least one sensor includes forming a plurality of sensors and circumferentially disposing the plurality of sensors around a portion of the elongate body.

[0018]

[0024] In one embodiment, emitting ultrasound from at least one sensor includes emitting ultrasound from each of a plurality of sensors to obtain an ultrasound image of the blood vessel.

[0019]

[0025] In one embodiment, forming at least one sensor of piezoelectric material includes screen printing the piezoelectric material onto a substrate.

[0026] In one embodiment, forming at least one sensor of piezoelectric material includes jet printing the piezoelectric material onto a substrate.

[0020]

[0027] In one embodiment, the method further includes forming at least one sensor on a polymeric film and then disposing the polymeric film on the elongate body.

[0028] In one embodiment, forming the at least one sensor of piezoelectric material includes forming the at least one sensor directly into at least one of the core wire or hypotube of the elongate body.

[0021]

[0029] The components, features, elements, steps, or acts of one embodiment may be combined with the components, features, elements, steps, or acts of other embodiments without limitation.

[0030] The foregoing and other advantages of various embodiments of the present disclosure will become apparent upon reading the following detailed description and upon reference to the drawings. [Brief description of the drawings]

[0022] [Figure 1]

[0031] 1 illustrates a guidewire system according to an embodiment of the present disclosure. [Diagram 2]

[0032] 1 is a side view of a distal portion of a guidewire according to an embodiment of the present disclosure. FIG. [Diagram 3]

[0033] 1 is a perspective view of a distal portion of a guidewire according to an embodiment of the present disclosure. FIG. [Figure 4]

[0034] 4A, 4B, and 4C are diagrams depicting acts in a manufacturing process associated with a guidewire according to an embodiment of the present disclosure. [Figure 5A]

[0035] 13A-13C are diagrams illustrating the use of a guidewire according to an embodiment of the present disclosure. [Figure 5B] 13A-13C are diagrams illustrating the use of a guidewire according to an embodiment of the present disclosure. [Figure 5C] 13A-13C are diagrams illustrating the use of a guidewire according to an embodiment of the present disclosure. [Figure 5D] 13A-13C are diagrams illustrating the use of a guidewire according to an embodiment of the present disclosure. [Figure 6A]

[0036] 11 is a graph illustrating the response of a guidewire constructed in accordance with an embodiment of the present disclosure. [Figure 6B] 11 is a graph illustrating the response of a guidewire constructed in accordance with an embodiment of the present disclosure. [Figure 6C] 11 is a graph illustrating the response of a guidewire constructed in accordance with an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023]

[0037] Various embodiments described herein are directed to medical devices, systems, and related methods, including the incorporation of sensors into medical devices, the manufacture of such sensors and devices, and the use of such sensors and devices.

[0024]

[0038] In some embodiments, devices associated with cardiovascular, neurovascular, and intravascular procedures are provided with sensors integrated therein. For example, a guidewire or catheter may include sensors integrated within the structure to detect or measure physiological data (e.g., blood pressure, flow rate, etc.) or provide imaging data, providing that data in real time during the associated procedure.

[0025]

[0039] In some embodiments, sensors, transducers, or electronic elements incorporated into the device may be formed by manufacturing techniques such as screen printing, aerosol jet printing, 3D printing, stereolithography, microlithography, or a combination of such manufacturing techniques and processes.

[0026]

[0040] Some non-limiting examples of medical devices that may incorporate such sensors include U.S. patent application Ser. No. 17 / 205,964, filed March 18, 2021, entitled "Guidewire for Imaging and Measurement of Pressure and Other Physiological Parameters," U.S. patent application Ser. No. 17 / 205,854, filed March 19, 2021, entitled "Catheter for Imaging and Measurement of Pressure and Other Physiological Parameters," U.S. patent application Ser. No. 17 / 205,754, filed March 18, 2021, entitled "Operatively Coupled Data and Power Transfer Device for Medical Guidewires and Catheters with Sensor," and U.S. patent application Ser. No. 17 / 205, No. 17 / 205,614, filed on March 18, 2021, entitled “Signal Transmission Device for Simultaneous Power and Data Transfer to and from Wireless Sensors Attached to Medical Devices,” and U.S. patent application Ser. No. 17 / 979,629, filed on November 2, 2022, entitled “Data and Power Transfer Devices for Use with Medical Devices and Related Methods,” and U.S. patent application Ser. No. 17 / 205,614, filed on March 18, 2021, entitled “Data and Power Transfer Devices for Use with Medical Devices and Related Methods,”No. 18 / 114,141, filed February 24, 2023, entitled "Medical Devices, Systems, and Methods Incorporating the Same," and U.S. Provisional Patent Application No. 63 / 394,591, filed August 2, 2022, entitled "Medical Devices, Systems, and Methods Including Power and Data Transfer," the disclosures of each of which are incorporated herein by reference in their entirety.

[0027]

[0041] 1, a guidewire system 100 is illustrated in accordance with an embodiment of the present disclosure. As shown, guidewire system 100 includes a wire 102 (which is an example of an "elongate body" or "elongate element" as used herein), a proximal device 104, one or more sensors 106 associated with wire 102, a controller 110 (shown enlarged and in schematic form) including a power source 112, a data signal processor 114, and optionally, a transmitter 116, as well as an external device 118 (e.g., a stationary or portable display, a tablet computer, or other input and / or output device) that may be in wired or wireless communication with transmitter 116.

[0028]

[0042] The proximal device 104 (which in some embodiments may be associated with the proximal portion and / or the intermediate portion, as defined below) may be configured as a data and / or power transfer device. For example, the proximal device 104 may be configured to electrically couple to the wires 102 to provide power to sensors or other electronics associated with the wires, and to receive various signals provided by the sensors or other electronic components. Such electrical coupling between the proximal device 104 and the wires 102 may be achieved by a conductive connection or by an electric field (e.g., through capacitive coupling). In some embodiments, the proximal device may include a hemostasis valve.

[0029]

[0043] The data signal processor 114 may be configured to receive sensor data signals transmitted through the wire 102 from one or more sensors 106 (which may be arranged or oriented in a particular pattern as individual sensors or may be configured as an identifiable sensor array) associated with the wire 102. The power source 112 may be configured to transmit power through the wire 102 to power the one or more sensors 106 and / or other components of the wire 102. The power source 112 may include an on-board power source, such as a battery or battery pack, and / or may include a wired connection to an external power source.

[0030]

[0044] The one or more sensors 106 may be positioned at any suitable location on the wire 102, but are typically disposed along the distal section that is expected to reach the target anatomy. As used herein, the "distal section" or "distal portion" refers to the most distal 30 cm of the device, the most distal 20 cm of the device, the most distal 15 cm of the device, the most distal 10 cm of the device, or a range using any two of the aforementioned values ​​as endpoints. In some embodiments, the "intermediate section" may be roughly considered the middle third of the device, and the "proximal section" or "proximal portion" may be roughly considered the proximal third of the device.

[0031]

[0045] In one embodiment, guidewire system 100 is configured to transmit power to one or more sensors 106 through individual traces or other electrical conductors, and data signals from one or more sensors 106 may be transmitted by a separate transmission structure or scheme. For example, data may be transmitted by additional traces or electrical conductors, by optical transmission, or by wireless transmission. In some embodiments, such transmission structures (e.g., traces) may be formed on / in or otherwise integrated with wire 102 using additive manufacturing techniques.

[0032]

[0046] In another embodiment, the guidewire system 100 is configured to transmit power and data signals through the actual wire 102 itself, rather than through traces or separate discrete electrical conductors. In some embodiments, multiple power and / or data signals (e.g., data signals from multiple sensors) may be transmitted simultaneously through the wire 102. The power and / or data signals may also be transmitted in a "continuous" format; that is, the power and / or data signals may have a sufficiently high sampling rate such that the information is provided to the user within a time frame that is effectively "real-time." Non-limiting examples of managing power and / or data signals, along with associated components and systems, are set forth in the previously incorporated U.S. patent documents.

[0033]

[0047] The wire 102 of the guidewire system 100 is configured for insertion into the body of a subject. The subject is typically a human, but in other implementations may be a non-human mammal or even a non-mammal. Any suitable route of administration may be utilized depending on the particular preference and / or application needs. Common routes include femoral, radial, and cervical, although the guidewire system 100 may utilize other access routes as desired.

[0034]

[0048] The wire 102 has a proximal end 107 and a distal end 109. The length of the wire 102 may vary depending on the particular application needs and the target anatomical region. By way of example, the wire 102 may have an overall length of about 50 cm to about 350 cm, more typically about 200 cm, from the proximal end 107 to the distal end 109, depending on the particular application needs and / or the particular anatomical target. The wire 102 may be sized such that the outer diameter (e.g., after application of other outer members) is about 0.008 inches to about 0.040 inches, although larger or smaller sizes may also be utilized depending on the particular application needs. For example, certain embodiments may have outer diameter sizes corresponding to standard guidewire sizes, such as 0.0254 cm, 0.03556 cm, 0.04064 cm, 0.04572 cm, 0.06096 cm, 0.0889 cm, 0.09652 cm, (0.010 inches, 0.014 inches, 0.016 inches, 0.018 inches, 0.024 inches, 0.035 inches, 0.038 inches), a size range having any combination of the aforementioned endpoints as endpoints, or other sizes as are common for guidewire devices. Wire 102 may be formed from stainless steel or other metals or alloys having similar suitable properties. In some embodiments, wire 102 may be formed from or include a conductive material of suitable mechanical properties.

[0035]

[0049] Considering that guidewires inherently have strict dimensional and performance (e.g., torque-ability, bending, pushability, stiffness, trackability, etc.) limitations and have limited space to function in, being able to reduce or eliminate extraneous components frees up limited space and allows for greater design flexibility. Additionally, being able to integrate various components, such as sensors or other electronic components, also provides a more versatile, practical, and durable device. The integration of sensors 106 or other electrical elements or components with wire 102 according to the embodiments described herein may enable the production of wire 102 with desired size and handling characteristics while also providing improved data capture and other functionality.

[0036]

[0050] 2 and 3, the one or more sensors 106 of the guidewire system 100 may be circumferentially arranged around the guidewire 102 in an array, with each sensor element 106 in electrical communication with a processor 120 (shown diagrammatically in FIG. 2) via a number of traces 122 or other conductors. In one embodiment, the processor 120 may include an application specific integrated circuit (ASIC). The processor 120 may be configured to control the operation of the sensors 106, such as those described in more detail below. In some embodiments, the processor 120 may include a chip with one or more additional sensors 124 (e.g., blood pressure sensors, flow sensors, temperature sensors, etc.) integrated therein.

[0037]

[0051] While generally referred to as a "sensor" when discussing various embodiments overall, it should be noted that a "sensor" and / or a "sensor component" (e.g., sensor 106) may comprise or be otherwise associated with a transducer or other component and may be configured as an input device, an output device, or both. In other words, the sensor components described herein may include or be part of a transducer capable of transmitting and / or receiving a particular type of signal. For example, such sensors may include ultrasonic transducers, optical emitters (e.g., light emitting diodes (LEDs)), optical sensors (e.g., photodiodes), and the like.

[0038]

[0052] In one particular embodiment, the sensor 106 may be configured as an ultrasound transducer formed of a piezoelectric material. In one embodiment, the piezoelectric material may be applied directly to the guidewire 102 (e.g., to the core wire, the hypotube, or to a housing structure coupled to the core wire or hypotube). In another embodiment, the piezoelectric material may be applied to a film or coating placed on the guidewire 102. For example, the piezoelectric material may be applied to a tube structure (e.g., polyimide) or other structure positioned over a portion of the guidewire 102 (and thus form a piezoelectric type ultrasound transducer thereon). In another embodiment, the piezoelectric material may be applied to a film (e.g., polyimide) while the film is in a flat state, and the film is then wrapped or otherwise conformally applied to the surface of the guidewire 102. Exemplary films include polyimide, polyamideimide (PAI), polybenzimidazole (PBI), polyphenylene oxide (PPO), polyetherimide (PEI), and combinations thereof.

[0039]

[0053] In one example, the piezoelectric material may include PiezoPaint™ available from Meggitt PLC of the UK. In one example, the piezoelectric material may exhibit one or more of the following electrical properties: a relative dielectric constant of approximately 80-100 at 1 kHz, a dielectric constant of approximately 2.5-3.5 at 1 kHz, and a dielectric constant of approximately 10-20 at 1 kHz. -2 a dissipation factor of about 0.25 μm, a Curie temperature (ceramic phase) of 330° C., or a recommended operating range of 80° C. In one example, the piezoelectric material may exhibit one or more of the following electromechanical properties: a coupling coefficient of about 8.2% thickness, a piezoelectric charge coefficient d of about 45 pC / N, 33 , a piezoelectric charge coefficient d of about 15 pC / N 31 , or a frequency constant of 1410 Hz m of thickness. In one embodiment, the piezoelectric material may exhibit one or more of the following mechanical characteristics: 6 kilograms / (seconds*meters 2 ) acoustic impedance equal to or less than 5.0 g / cm 3 a density of 0.01 gPa, a Young's modulus of 29 GPa, or a Poisson's ratio of 0.3. The piezoelectric material may also exhibit a low cure temperature of less than approximately 100° C. Such characteristics and properties are provided by way of example and should not be considered limiting.

[0040]

[0054] 4A-4C, a method of forming a sensor 106 on a substrate (e.g., on a polyimide film) is illustrated according to one embodiment of the present disclosure. As shown in FIG. 4A, a screen 140 having various openings 142 formed therein is positioned about a substrate 144. The substrate 144 may include a film (e.g., a polyimide film) such as those discussed above. In other embodiments, the substrate 144 may be formed as a non-planar geometric structure (e.g., a tube). In some embodiments, the substrate 144 may include components of the guidewire 102 (e.g., a core wire, hypotube, housing structure).

[0041]

[0055] The opening 142 in the screen may be configured to represent the desired shape in which the sensor is to be formed. For example, the screen 140 is shown in cross-section to depict a square or rectangular opening 142. However, the opening may extend a desired length into (and / or out of) the page to provide or define the "length" of the resulting sensor. Of course, the sensor (and thus the opening) may take on other shapes or geometries.

[0042]

[0056] A mass of piezoelectric material 146 is positioned on the upper portion of the screen 140, and a squeegee 148 is used to distribute the piezoelectric material into the openings and to the desired locations on the substrate 144. For example, a downward force is applied to the screen 140 by the squeegee 148, as indicated by arrow 150, to bring at least a portion of the screen 140 into contact with the substrate as the squeegee 148 is dragged across the screen 140. While the downward force is being applied by the squeegee 148, the squeegee 148 is also dragged or run across the screen 140, as indicated by arrow 152, to press or fill the piezoelectric material 146 into the openings 142 to form the physical structure of the sensor 106 on the substrate, as illustrated in Figures 4B and 4C. The resulting structure may then be cured to provide a structure that may be used as an ultrasonic transducer that may both emit and detect ultrasonic waves.

[0043]

[0057] In some embodiments, the substrate 144 may be wound onto a wire or other structure as desired. In some embodiments, a filler material (e.g., a polyimide material) is disposed between adjacent sensors 106 to create a substantially continuous surface between adjacent sensors. In some embodiments, a coating material may be disposed over the sensors. The formed sensors 106 may be coupled to other electrical components via traces or other conductors as discussed above.

[0044]

[0058] In other embodiments, other manufacturing processes and techniques may be used, as noted above, including various spraying, printing, and additive manufacturing techniques.

[0059] 5A-5D, an example of a guidewire 102 being used as an imaging device is illustrated. As shown in FIG. 5A, a cross section of the guidewire 102 is depicted as shown by cross section 5-5 in FIG. 3 while it is positioned within a blood vessel 160. In the embodiment shown in FIG. 5A-5D, 16 individual sensors (106a-106p) are circumferentially positioned on the guidewire 102, although other embodiments may include a greater or lesser number of sensors. For example, one embodiment may include eight sensors with a pitch of 125 microns (μm). In another embodiment, 16 sensors may be used with a 62.5 μm pitch. In yet another embodiment, 32 sensors may be used with a 31 μm pitch. In other embodiments, the pitch may be greater or less than the example values ​​provided above. In various embodiments, the number of sensors and the pitch of the sensors may depend at least in part on the desired size (e.g., diameter) of the guidewire. In some cases, the number, size, and / or pitch of the sensors may depend in part on the desired resolution of the resulting image to be acquired by the device.

[0045]

[0060] In an embodiment with 16 sensors 106, each sensor covers 22.5 degrees. If the width is smaller than the emission wavelength divided by two (e.g., 75 μm at 20 MHz), the elements will see each other's reflections. For example, the first sensor 106a (configured as an ultrasound transducer) may emit ultrasound waves in a direction substantially normal (perpendicular) to the radial surface of the first sensor, which are reflected (at least partially) from the wall of the blood vessel 160. Upon returning, the reflection is detected by adjacent sensors (e.g., sensors 106b, 106c, 106o, and 106p). Note that the emitted ultrasound waves are shown by solid lines, while the reflected waves are shown by dashed lines.

[0046]

[0061] Knowing the geometry of the sensors 106, the characteristics of the ultrasound, and the response time of the reflection (e.g., the amount of time that elapses between the emission of the ultrasound and the detection of the reflection by a particular sensor), the distance of a particular point on the blood vessel from the receiving sensor (e.g., 106b, 106c, 106o, and 106p) can be determined. In some other cases, the same emitting sensor 106a can also be used as the receiver sensor in a monostatic fashion. This process can be repeated using a different sensor as the emitting sensor. For example, FIG. 5B shows the emitting sensor as sensor 106b, FIG. 5C shows the emitting sensor as sensor 106c, and FIG. 5D shows the emitting sensor as sensor 106d. In each case, the sensor located adjacent to the emitting sensor (e.g., one or more sensors on either side of the emitting sensor) can be the detecting sensor, and the process can be repeated as necessary so that all of the sensors (106a-106p) can be emitting sensors. This entire process may occur many times per second such that the entire circumference of the blood vessel may be imaged while the guidewire 102 is pulled back or otherwise displaced through the vessel.

[0047]

[0062] In addition to the timing of the sensor for distance determination, the amplitude of the reflection may provide information about the local reflectivity of the vessel wall. For example, if calcification is present in the vessel wall, the reflected signal may be stronger (higher in amplitude) compared to areas of the vessel lumen without calcification. Thus, by recording and processing the reflected signal, information about the pathology of the vessel may also be obtained, for example, the arc of calcification covering the lumen. Using the pullback method for measurement, the length of the calcification may also be measured.

[0048]

[0063] In some embodiments, due to the size of the sensor 106 on the guidewire (also considering the intended size of the resulting guidewire device), the material used to form the sensor 106, and other related factors, the resolution of the resulting ultrasound image may be lower than that obtained, for example, by a larger IVUS catheter using a pMUT or cMUT imaging transducer. However, even reduced resolution images may provide benefits when generated by a smaller, less invasive device such as a guidewire. For example, the use of a guidewire device as disclosed herein allows for ultrasound imaging and / or lumen sizing information without the need for subsequent catheter insertion, allowing for a shorter and simpler procedure, at least in some cases. Additionally, even if the resolution is reduced relative to a conventional IVUS catheter procedure, the sensor 106 may provide lumen sizing of a particular blood vessel. Thus, a reduced area or neck-like area within a blood vessel may provide an indication of a stenosis or other abnormality requiring treatment.

[0049]

[0064] At least some embodiments of the disclosed guidewire devices are smaller than conventional IVUS catheters. For example, while typical IVUS catheters are 2.6 Fr to 3.5 Fr (0.034 inches to 0.046 inches), the guidewire devices disclosed herein may have sizes less than 0.034 inches, such as 0.028 inches or less, 0.024 inches or less, 0.018 inches or less, or 0.014 inches or less, including sizes down to about 0.010 inches. Thus, the guidewire devices disclosed herein allow imaging and / or lumen size determination using intravascular device sizes smaller than those used in conventional IVUS procedures.

[0050]

[0065] 6A-6C, several graphs are provided illustrating the response of a sensor formed in accordance with the embodiment described with respect to FIGS. 4A-4C. The graphs show the reflection detected by an ultrasound sensor disposed in blood and positioned at a known distance from an interface (mimicking a blood vessel wall). The sensor detects reflections at 0.1 mm 2 The sensor was formed to present a 30μ area (i.e., 0.1 mm×1.0 mm) and was 30μ thick. The sensor was formed on a polymeric material including polyimide disposed on a core material including steel (e.g., mimicking a guidewire core or hypotube). FIG. 6A represents the response time when the sensor was formed on a 5 μm thick polymeric material and positioned 0.5 mm away from the reflective interface, FIG. 6B represents the response time when the sensor was formed on a 15 μm thick polymeric material and positioned 0.5 mm away from the reflective interface, and FIG. 6C represents the response time when the sensor was formed on a 30 μm thick polymeric material and positioned 1 mm away from the reflective interface. The units of the vertical or Y axis are in Volts, while the units of the horizontal or X axis are in microseconds.

[0051]

[0066] It should be noted that although the example embodiments are described with respect to a guidewire, various aspects of the present disclosure may be implemented with other devices, such as catheters or implantable devices, and the present disclosure should not be considered as limited to guidewires.

[0052]

[0067] The use of "adapted to" or "configured to" herein means open and inclusive language that does not exclude devices that are adapted or configured to perform additional tasks or steps. Additionally, the use of "based on" means open and inclusive in that a process, step, calculation, or other operation "based on" one or more recited conditions or values ​​may in fact be based on additional conditions or values ​​other than those recited. The headings, lists, and numbering contained herein are for ease of description only and are not meant to be limiting.

[0053]

[0068] Numerical values ​​disclosed herein may be optionally modified by adding the term "about" or its synonyms. When the term "about," "approximately," "substantially," "roughly," or the like is used in conjunction with a stated amount, value, or condition, it may be taken to mean that the amount, value, or condition deviates by less than 15%, less than 10%, less than 5%, less than 1%, less than 0.1%, or less than 0.01% of the stated amount, value, or condition.

[0054]

[0069] While the described embodiments are susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and are described in detail herein. It should be noted, however, that the invention is not intended to be limited to the specific forms disclosed, and that elements, features, elements, steps, or acts of one embodiment may be combined with elements, features, elements, steps, or acts of other embodiments without limitation. Rather, the invention includes all modifications, equivalents, and alternatives falling within the spirit and scope defined by the appended claims that follow.

Claims

1. With elongated elements, At least one sensor including a piezoelectric material having a cure temperature of about 100° C. or less or an acoustic impedance of about 14 MRayl or less; A guidewire comprising:

2. The guidewire of claim 1 , wherein the at least one sensor comprises a plurality of sensors circumferentially disposed about a portion of the elongate element.

3. The guidewire of claim 2 , wherein the plurality of sensors includes at least eight sensors.

4. The guidewire of claim 2 , wherein the plurality of sensors exhibits a pitch of approximately 125 microns (μm) or less.

5. The guidewire of claim 2 , wherein the plurality of sensors exhibit a pitch of approximately 62.5 microns (μm) or less.

6. The guidewire of claim 2 , wherein the plurality of sensors exhibits a pitch of approximately 31 microns (μm) or less.

7. The guidewire of claim 1 , wherein the elongate element comprises at least one of a core wire or a hypotube, and the at least one sensor is formed directly on the core wire or the hypotube.

8. The guidewire of claim 1 , wherein the at least one sensor is formed on a polymeric film.

9. The guidewire of claim 9 , wherein the polymeric film comprises polyimide.

10. The guidewire of claim 9 , wherein the polymeric film is disposed over a core wire or a hypotube.

11. 11. The guidewire of claim 1, wherein the elongate element of the guidewire has an outer diameter of less than 0.034 inches.

12. Providing an elongate body; forming at least one sensor of a piezoelectric material at a temperature of approximately 100° C. or less and an acoustic impedance of approximately 14 MRayl or less, positioning the at least one sensor along a portion of the elongated body; A method comprising:

13. positioning the sensor within a blood vessel; emitting ultrasonic waves from the at least one sensor to determine a characteristic of the blood vessel; The method of claim 12 further comprising:

14. The method of claim 13 , further comprising detecting reflections of the emitted ultrasound waves to determine the characteristics of the blood vessel.

15. The method of claim 14 , wherein the characteristics of the blood vessel include a size of a lumen of the blood vessel.

16. The method of claim 13 , wherein forming the at least one sensor comprises forming a plurality of sensors and circumferentially disposing the plurality of sensors around the portion of the elongate body.

17. 17. The method of claim 16, wherein emitting ultrasound from at least one sensor comprises emitting ultrasound from each of the plurality of sensors to obtain an ultrasound image of the blood vessel.

18. The method of claim 12 , wherein forming at least one sensor of piezoelectric material comprises screen printing the piezoelectric material onto a substrate.

19. The method of claim 12 , wherein forming at least one sensor of the piezoelectric material comprises jet printing the piezoelectric material onto a substrate.

20. The method of claim 12 , further comprising forming the at least one sensor on a polymeric film and then disposing the polymeric film on the elongate body.

21. The method of claim 12 , wherein forming the at least one sensor of piezoelectric material comprises forming the at least one sensor directly into at least one of a core wire or a hypotube of an elongate body.

22. 18. The method of any one of claims 13 to 17, wherein the elongate body comprises a wire of a guidewire device, and the characteristics of the blood vessel are determined without passing a catheter through the blood vessel.

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