Catheter for image acquisition

Abstract

[Problem] To provide a catheter for image acquisition in which bonding strength between an outer tube, a film sensor, and a support is increased. [Solution] A catheter (100) for image acquisition includes: an inner tube (10) having a first lumen (15) extending in the axial direction; a sensor unit (30) arranged at a tip-end portion (11) of the inner tube and having a plurality of transducers (45a) circumferentially arranged in a ring shape, the transducers for transmitting and receiving ultrasound within a biological lumen; and an outer tube (20) arranged so as to cover at least a portion of the inner tube at a position closer to the base-end side than the sensor unit so as to form a second lumen (25) between the sensor unit and the inner tube. The sensor unit includes a film sensor (40) having a plurality of transducers arranged thereon, and a support (50) for supporting the film sensor, where at least a portion of the film sensor is sandwiched between the support and the outer tube.

Description

Catheter for image acquisition

[0001] The present invention relates to a catheter for image acquisition.

[0002] In the treatment of lesions such as stenotic or occlusive portions that occur in a living body lumen such as a blood vessel, an image acquisition catheter using intravascular ultrasound diagnosis (IVUS: Intravascular Ultrasound) is used as a medical device for acquiring diagnostic images in order to observe these properties or the state after treatment (see Patent Document 1).

[0003] The catheter for image acquisition of Patent Document 1 includes a flexible substrate (film sensor) provided integrally with a transducer (transducer array), a support for supporting the flexible substrate, and a long member (shaft portion) in which the flexible substrate and the support are disposed at the tip. The flexible substrate is provided with signal lines for connecting to a wiring portion (cable) for transmitting and receiving various electrical signals between the transducer array and an external device.

[0004] WO2020 / 038830

[0005] In a configuration in which a support for supporting a flexible substrate is disposed at the tip of a long member as in the catheter for image acquisition described in Patent Document 1, if the joining (fixing) between the shaft portion, the film sensor, and the support is released, the conduction between the signal line provided on the flexible substrate and the wiring portion is interrupted. For example, in order to prevent falling into such a situation, a reinforcing material such as an adhesive can be used to increase the joining strength of the shaft portion, the film sensor, and the support, but it may be difficult to ensure sufficient joining strength only by using the reinforcing material.

[0006] The present invention has been made based on the above problems, and an object thereof is to provide a catheter for image acquisition in which the joining strength of an outer tube, a film sensor, and a support is increased.

[0007] The present invention can be achieved by means according to any one of the following (1) to (10).

[0008] (1) An image acquisition catheter for acquiring diagnostic ultrasound tomographic images in a biological lumen, comprising: an inner tube having a first lumen extending in the axial direction; a sensor section disposed at the tip of the inner tube, wherein a plurality of transducers for transmitting and receiving ultrasound in the biological lumen are arranged in a ring shape in the circumferential direction; and an outer tube disposed at a position closer to the proximal end than the sensor section so as to cover at least a portion of the inner tube, forming a second lumen between the outer tube and the outer tube, wherein the sensor section comprises a film sensor on which the plurality of transducers are arranged, and a support for supporting the film sensor, and at least a portion of the film sensor is sandwiched between the support and the outer tube.

[0009] (2) The image acquisition catheter according to (1), wherein the base end of the support has a tapered portion whose outer diameter gradually decreases toward the base end in the axial direction, and the tip of the outer tube is fitted to the support with at least a part of the film sensor sandwiched between it and the tapered portion of the support.

[0010] (3) The image acquisition catheter according to (2), wherein the tip of the outer tube has a tapered shape in which the outer diameter increases toward the tip, corresponding to the tapered portion of the support.

[0011] (4) An image acquisition catheter according to any one of (1) to (3), wherein the film sensor has a wiring section connected to it that enables the transmission of electrical signals between the plurality of transducers and an external device, the proximal end of the film sensor is positioned on the proximal end side of the position where it is sandwiched between the support and the outer tube, and the wiring section is connected to the proximal end of the film sensor.

[0012] (5) The image acquisition catheter according to any one of (1) to (4), further comprising a reinforcing member that reinforces the fixing of the support and the outer tube at a position where the film sensor is sandwiched between the support and the outer tube.

[0013] (6) The imaging catheter according to any one of (1) to (5), wherein the proximal region located in a certain range from the proximal end of the outer tube toward the proximal end has a greater wall thickness and outer diameter than the proximal region located in a certain range from the tip of the outer tube toward the proximal end.

[0014] (7) The image acquisition catheter according to (6), which is located between the proximal region and the tip region and has an intermediate region in which the wall thickness and outer diameter gradually decrease from the proximal side to the tip side.

[0015] (8) The image acquisition catheter according to (7), wherein the second lumen has a substantially constant inner diameter in the tip region, the intermediate region, and the proximal region.

[0016] (9) An image acquisition catheter according to any one of (6) to (8), having a wiring section connected to the film sensor and enabling the transmission of electrical signals between the plurality of transducers and an external device, wherein the wiring section is made of a flat cable and is arranged along the outer circumference of the inner tube.

[0017] (10) An imaging catheter according to any one of (6) to (9), having ring-shaped radiopaque markers attached at equal intervals to the outer surface of the inner tube, or coil-type radiopaque markers wound in a sparse and dense manner along the outer surface of the inner tube.

[0018] In the image acquisition catheter of the present invention, at least a portion of the film sensor is sandwiched between the support and the outer tube. Therefore, the bonding strength between the outer tube, the film sensor, and the support can be effectively increased.

[0019] This is a schematic diagram of a medical system including an image acquisition catheter according to an embodiment. This is a diagram showing an image acquisition catheter according to an embodiment. This is a cross-sectional view of an image acquisition catheter according to an embodiment. This is a perspective view of a support according to an embodiment. This is a cross-sectional view of a support according to an embodiment. This is an enlarged cross-sectional view of the vicinity of the tip of the inner tube of the image acquisition catheter according to an embodiment. This is an enlarged cross-sectional view of the vicinity of the tip of the outer tube of the image acquisition catheter according to an embodiment. This is an enlarged cross-sectional view of a part of the image acquisition catheter according to an embodiment. This is a cross-sectional view along the line of arrow 9A-9A shown in Figure 8. This is a cross-sectional view along the line of arrow 10A-10A shown in Figure 8. This is a cross-sectional view along the line of arrow 11A-11A shown in Figure 8.

[0020] Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. The embodiments shown herein are illustrative examples for embodying the technical idea of ​​the present invention and do not limit the present invention. Furthermore, all other implementable forms, examples, and operational techniques that can be conceived by those skilled in the art without departing from the spirit of the present invention are included in the scope and spirit of the present invention, as well as in the claims and their equivalents.

[0021] Furthermore, the drawings attached to this specification may be schematically represented with changes to scale, aspect ratio, shape, etc., from the actual object for the sake of illustration and ease of understanding, but these are merely examples and do not limit the interpretation of the present invention.

[0022] For the sake of clarity, the following directions are defined in this specification. In each figure, the "axial direction" is the direction along the central axis c1 of the image acquisition catheter 100. The "circumferential direction" is the rotational direction with the central axis c1 of the image acquisition catheter 100 as the reference axis.

[0023] Furthermore, the arrows X1-X2 in each figure indicate the axial direction of the image acquisition catheter 100, the arrows Y1-Y2 indicate the depth direction perpendicular to the axial direction, and the arrows Z1-Z2 indicate the height direction perpendicular to both the axial direction and the depth direction. The cross section perpendicular to the axial direction (Y1-Y2 / Z1-Z2 cross section) is also referred to as the orthoaxial cross section.

[0024] In the image acquisition catheter 100, the side where the proximal hub portion 90 is located is referred to as the "proximal end." The side of the image acquisition catheter 100 that is located opposite the proximal end and is introduced into the body is referred to as the "proximal end." Furthermore, "proximal end" refers to the portion that includes a certain range extending from the tip (extent) towards the proximal end, and "proximal end" refers to the portion that includes a certain range extending from the proximal end (very proximal end) towards the proximal end.

[0025] In this embodiment, the image acquisition catheter 100 is configured as an IVUS catheter utilizing intravascular ultrasound (IVUS).

[0026] In this embodiment, blood vessels are given as an example of a biological lumen to which the image acquisition catheter 100 is applied. However, the biological lumen to which the image acquisition catheter 100 is applied is not limited to blood vessels, and may also be other biological organs such as the bile duct, trachea, esophagus, other digestive tract organs, urethra, ear, nose, and throat lumen, etc.

[0027] <Medical System 1> As shown in Figure 1, the medical system 1 includes an image acquisition catheter 100 and an external device 300.

[0028] Medical system 1 is used to diagnose the characteristics of a lesion by inserting an image acquisition catheter 100 into the patient's blood vessels, delivering the sensor unit 30 to the lesion, and outputting images (such as cross-sectional images of blood vessels) taken at and around the lesion to an external device 300.

[0029] <Image Acquisition Catheter 100> Referring to Figures 1 to 3, the image acquisition catheter 100 comprises an inner tube 10 having a first lumen 15 extending in the axial direction, a sensor section 30 positioned at the tip 11 of the inner tube 10 and having a plurality of transducers 45a arranged in a ring shape in the circumferential direction for transmitting and receiving ultrasound within the biological lumen, and an outer tube 20 positioned on the proximal end side of the sensor section 30 and covering at least a part of the inner tube 10 so as to form a second lumen 25 between itself and the inner tube 10.

[0030] The image acquisition catheter 100 is configured as a so-called "over-the-wire type catheter," in which a guidewire can be inserted and removed from the first port 91 of the proximal hub section 90 through the first lumen 15 of the inner tube 10. However, the image acquisition catheter 100 may also be configured as a so-called "rapid exchange type catheter."

[0031] <Inner tube 10> The inner tube 10 is a long tubular member having a first lumen 15 that extends from the tip 11 to the base 13.

[0032] A guidewire can be inserted through the first lumen 15 to guide the movement of the imaging catheter 100 within the biological lumen. The inner diameter Di, outer diameter Do, and wall thickness T of the inner tube 10 can be configured to be approximately constant along the axial direction (see Figures 9 to 11).

[0033] The tip 11 of the inner tube 10 is provided with a tip opening 11a for inserting a guidewire into the first lumen 15. The proximal end 13 of the inner tube 10 is provided with a proximal end opening 13a for guiding the guidewire, which has been inserted into the first lumen 15, to the proximal end of the image acquisition catheter 100.

[0034] The constituent material of the inner tube 10 is a material applicable to catheters and the like, and various thermoplastic elastomers such as styrene-based, polyolefin-based, polyurethane-based, polyester-based, polyamide-based, polyimide-based, polybutadiene-based, trans-polyisoprene-based, fluororubber-based, and chlorinated polyethylene-based materials can be used.

[0035] As shown in Figures 2 and 3, a tip member 80 (tip) can be attached near the tip 11 of the inner tube 10. The tip member 80 can be made of, for example, a resin material with relatively high flexibility. The tip member 80 can be joined (fixed) to the support 50 of the sensor unit 30 by, for example, a joint 85.

[0036] The tip member 80 can be configured to have a tapered portion 81 whose outer diameter gradually decreases towards the tip. This improves the ease with which the image acquisition catheter 100 can be inserted into a biological lumen.

[0037] <Sensor Unit 30> As shown in Figures 3 to 8, the sensor unit 30 includes a film sensor 40 on which a plurality of transducers 45a are arranged, and a support 50 that supports the film sensor 40.

[0038] The film sensor 40 can be made of a flexible substrate on which electronic components are mounted on a film substrate. An electronic circuit including a plurality of transducers 45a, etc., is formed on the surface of the film sensor 40. The film sensor 40 is held in a state where it is wound around the tip 51 and base 53 of the support 50.

[0039] Each transducer 45a is equipped with a transducer made of a piezoelectric material having piezoelectric properties, such as ceramics or quartz, which can convert electrical signals into ultrasonic vibrations. When the film sensor 40 is wound around the support 50, the transducers 45a form a phased array arranged in a ring shape along the circumferential direction of the support 50. By using the phased array type sensor configured as described above, the sensor unit 30 can acquire tomographic images of blood vessels over a wide area in the circumferential direction all at once without rotating the sensor unit 30. There are no particular restrictions on the type, arrangement, or number of transducers 45a.

[0040] Multiple transducers 45a have the function of transmitting ultrasound based on electrical signals (pulse signals) into a biological lumen and receiving ultrasound reflected from biological tissue within the biological lumen. Each transducer 45a is positioned on the surface of the film sensor 40 and is connected to the multiplexer 45b.

[0041] The multiplexer 45b is a combinational circuit that selects one from a plurality of input lines and connects it to a single output line. Each of the transducers 45a is connected to each of a plurality of signal lines 45d formed on the film sensor 40 via the multiplexer 45b. Each of the transducers 45a is configured such that each of the transmission and reception operations can be sequentially switched by the multiplexer 45b. That is, the plurality of transducers 45a sequentially receive each received signal and sequentially transmit the signals received via the multiplexer 45b. The multiplexer 45b is driven and controlled by a control IC 45c formed on the film sensor 40.

[0042] The signal line 45d formed on the film sensor 40 extends to the vicinity of the base end portion 43 of the film sensor 40. A wiring portion 60 is connected to the film sensor 40. The sensor unit 30 can transmit and receive various signals to and from the control unit 310 of the external device 300 via the signal line 45d and the wiring portion 60.

[0043] <Support 50> As shown in FIGS. 4 to 7, the support 50 has a tip portion 51, a base end portion 53, a shaft portion 54 extending between the tip portion 51 and the base end portion 53, and a lumen 55 that communicates between the tip portion 51 and the base end portion 53 and through which the inner tube 10 is inserted.

[0044] The tip portion 51 has a straight portion 51a having a substantially constant outer diameter along the axial direction, and a tapered portion 51b located on the tip side of the straight portion 51a and having a gradually decreasing outer diameter toward the tip side in the axial direction.

[0045] As shown in FIG. 6, a tip member 80 can be fixed to the tip portion 51 of the support 50. There are no particular restrictions on the specific position and range for fixing the tip member 80 to the tip portion 51. For example, any position on the tip surface of the support 50 can be selected.

[0046] As shown in FIG. 6, the tip portion 41 of the film sensor 40 is wound around the outer peripheral surface of the straight portion 51a of the tip portion 51 of the support 50. The tip portion 41 of the film sensor 40 can be joined to the tip member 80 by a reinforcing material 72.

[0047] The proximal end portion 53 has a straight portion 53a having a substantially constant outer diameter along the axial direction, and a tapered portion 53b located on the proximal end side of the straight portion 53a and having a gradually decreasing outer diameter toward the proximal end side in the axial direction.

[0048] As shown in FIG. 7, a part of the film sensor 40 is wound around the outer peripheral surface of the straight portion 53a of the proximal end portion 53 of the support 50.

[0049] The shaft portion 54 of the support 50 has an outer diameter smaller than that of the straight portion 51a of the distal end portion 51 and the straight portion 53a of the proximal end portion 53. As shown in FIGS. 6 and 7, in a state where the film sensor 40 is wound around the support 50, a holding space 54a filled with a filling material 56 is defined between the film sensor 40 and the shaft portion 54. The filling material 56 can be constituted by, for example, a resin member obtained by curing a resin-based bonding material (such as an adhesive). The film sensor 40 has an increased bonding force with the support 50 through the filling material 56.

[0050] The support 50 can be constituted by, for example, a metal material for a part or the whole. For example, the support 50 may be integrally constituted by a metal material for the two straight portions 51a, 53a and the shaft portion 54, and the two tapered portions 51b, 53b may be constituted by resin members.

[0051] As shown in FIG. 7, at least a part of the film sensor 40 is sandwiched between the support 50 and the outer tube 20. Therefore, at least a part of the film sensor 40 is sandwiched by the support 50 and the outer tube 20. Thereby, the bonding strength of the outer tube 20, the film sensor 40, and the support 50 can be increased.

[0052] In procedures using the image acquisition catheter 100, when moving the tip 21 of the outer tube 20 to a bent portion of the biological lumen, fractures and other damage are likely to occur near the joint between the support 50 and the outer tube 20. This is because stress concentration is likely to occur near the joint between the support 50 and the outer tube 20, and because of the difference in physical properties between the support 50, which is made of a relatively rigid material such as metal, and the outer tube 20, which is made of a relatively flexible material such as resin. In this embodiment, as described above, the joint strength between each component is increased by sandwiching at least a part of the film sensor 40 between the support 50 and the outer tube 20. Therefore, compared to the case where these components are joined only with a reinforcing material (e.g., adhesive), it is possible to effectively prevent fractures and other damage near the joint.

[0053] As mentioned above, the base end 53 of the support 50 has a tapered portion 53b whose outer diameter gradually decreases toward the base end in the axial direction (see Figure 5). As shown in Figure 7, the tip portion 21 of the outer tube 20 is fitted to the support 50 with at least a part of the film sensor 40 sandwiched between it and the tapered portion 53b of the support 50. Therefore, at least a part of the film sensor 40 is more firmly joined to the support 50 by the tip portion 21 of the outer tube 20 fitted into the tapered portion 53b of the support 50. In addition, because the tapered portion 53b of the base end 53 of the support 50 has a shape in which the outer diameter gradually decreases toward the base end, the outer tube 20 can be smoothly fitted to the tapered portion 53b by pushing the tip portion 21 of the outer tube 20 along the tapered portion 53b.

[0054] As shown in Figure 7, the tip portion 21 of the outer tube 20 has a tapered shape in which the outer diameter increases toward the tip, corresponding to the tapered portion 53b of the base portion 53 of the support 50. As will be described later, the outer tube 20 can be made of, for example, a resin material. Therefore, when the outer tube 20 is pushed along the tapered portion 53b from the base end to the tip so as to sandwich at least a part of the film sensor 40 between it and the tapered portion 53b of the base portion 53 of the support 50, the tip portion 21 of the outer tube 20 expands toward the tip in accordance with the shape of the tapered portion 53b. By sandwiching at least a part of the film sensor 40 between the tapered portion 53b of the base portion 53 of the support 50 and the tip portion 21 of the outer tube 20, which has an outer diameter that increases toward the tip, the bonding strength of the outer tube 20, the film sensor 40, and the support 50 can be more effectively increased.

[0055] The image acquisition catheter 100 is connected to the film sensor 40 and has a wiring section 60 (see Figure 8) that enables the transmission of electrical signals between a plurality of transducers 45a and an external device 300. As shown in Figure 7, the proximal end 43 of the film sensor 40 is positioned on the proximal side of the position where it is sandwiched between the support 50 and the outer tube 20. The tip 61 of the wiring section 60 is connected to the proximal end 43 of the film sensor 40.

[0056] The base end 43 of the film sensor 40 can be connected to the tip 61 of the wiring section 60 by soldering or the like, while the signal line 45d provided on the film sensor 40 and the conductor section 66 of the wiring section 60 (see Figures 9 to 11) are electrically connected.

[0057] As mentioned above, in procedures using the image acquisition catheter 100, when moving the tip 21 of the outer tube 20 to a bent portion of the biological lumen, stress concentration tends to occur near the joint between the outer tube 20 and the support 50. Therefore, if the connection between the film sensor 40 and the wiring section 60 is placed at such a joint, there is a risk of the film sensor 40 breaking or the wiring section 60 breaking. To address this problem, the image acquisition catheter 100 positions the proximal end 43 of the film sensor 40, which is connected to the wiring section 60, at a predetermined distance towards the proximal end from the position where the film sensor 40 is sandwiched between the support 50 and the outer tube 20 (the clamped position). Therefore, it is possible to effectively prevent the film sensor 40 from breaking or the wiring section 60 from breaking near the connection between the film sensor 40 and the wiring section 60.

[0058] There are no particular restrictions on the specific position where the connection between the base end 43 of the film sensor 40 and the tip 61 of the wiring section 60 is located, but for example, it can be set at a position 0.1 mm to 10 mm away from the base end of the support 50 towards the base end.

[0059] The image acquisition catheter 100 may further include a reinforcing member 71 that reinforces the fixation (joining) of the support body 50 and the outer tube 20 at the position where the film sensor 40 is sandwiched between the support body 50 and the outer tube 20. By having the reinforcing member 71, the image acquisition catheter 100 can more effectively increase the bonding strength of the outer tube 20, the film sensor 40, and the support body 50.

[0060] Furthermore, as mentioned above, the portion where the base end 43 of the film sensor 40 and the tip 61 of the wiring portion 60 are connected is positioned at a location shifted toward the base end from the position where the film sensor 40 is sandwiched between the support 50 and the outer tube 20. If the base end 43 of the film sensor 40 and the tip 61 of the wiring portion 60 were positioned where the reinforcing material 71 is located, when the image acquisition catheter 100 is moved through a bent portion of the biological lumen, the reinforcing material 71 would deform flexibly in accordance with the bending, and excessive deformation of the base end 43 of the film sensor 40 and the tip 61 of the wiring portion 60 could occur to follow this deformation. As a result, fracture or disconnection of the wires may be induced due to the difference in physical properties between the reinforcing material 71 and each component 40, 60. In this embodiment, even if deformation such as bending occurs in the outer tube 20 near the position where the reinforcing material 71 is located as described above, fracture or disconnection of the wires of the film sensor 40 and the wiring portion 60 can be effectively prevented.

[0061] Furthermore, as mentioned above, the image acquisition catheter 100 employs a structure in which at least a portion of the film sensor 40 is sandwiched between the support 50 and the outer tube 20, thereby increasing the bonding strength between the outer tube 20, the film sensor 40, and the support 50. As a result, even when reinforcing material 71 is used, the amount of reinforcing material 71 used can be reduced. This makes it possible to reduce the diameter of the bonding position between the outer tube 20, the film sensor 40, and the support 50. Therefore, when moving the image acquisition catheter 100 along curved parts in the biological lumen, its ability to follow curved parts in the biological lumen can be improved, enabling easier passage.

[0062] As shown in Figure 7, the reinforcing material 71 can be placed in a predetermined area on the outer surface side (outer surface side of the outer tube 20) of the position where the film sensor 40 is sandwiched between the support body 50 and the outer tube 20, and in a part of the area between the inner tube 10 and the outer tube 20 (second lumen 25). By placing the reinforcing material 71 in such a position, the support body 50, the outer tube 20, the inner tube 10, and the film sensor 40 can be joined to each other near the position where the film sensor 40 is sandwiched between the support body 50 and the outer tube 20.

[0063] In the image acquisition catheter 100, the filler material 56, reinforcing materials 71, 72, and joint 85 used for joining members and reinforcing joint strength can each be made of, for example, a resin-based adhesive. As the resin-based adhesive, for example, one that is fluid when applied and hardens through a chemical change based on a curing treatment after application can be used. Examples of such materials include UV-curing adhesives and thermosetting adhesives (epoxy adhesives, etc.).

[0064] <Outer tube 20> The outer tube 20 is positioned to form a second lumen 25 between itself and the inner tube 10.

[0065] As shown in Figure 3, the base end 23 of the outer tube 20 is located on the tip side of the second port 92 of the hand hub portion 90. The base end opening 23a formed in the base end 23 of the outer tube 20 is arranged to communicate with the second port 92. The wiring portion 60 connected to the film sensor 40 is inserted through the second lumen 25 and then led out from the second port 92.

[0066] The outer tube 20 is arranged coaxially with the inner tube 10. The outer tube 20 can be made of the same material as the material exemplified above for the inner tube 10.

[0067] As described above, the tip portion 21 of the outer tube 20 is positioned to sandwich at least a part of the film sensor 40 between itself and the support 50. Furthermore, the tip portion 21 of the outer tube 20 has a tapered shape corresponding to the shape of the tapered portion 53b of the base end portion 53 of the support 50.

[0068] As shown in Figures 3 and 8, the outer tube 20 has a base end region 20C located in a certain range extending from the base end 23 toward the tip end of the outer tube 20.

[0069] The base end region 20C has a larger wall thickness t3 and outer diameter do3 than the tip region 20A, which is located in a certain range extending from the tip portion 21 of the outer tube 20 toward the base end.

[0070] Figure 9 shows a cross-sectional view perpendicular to the axis at an arbitrary position in the tip region 20A. Figure 11 shows a cross-sectional view perpendicular to the axis at an arbitrary position in the base region 20C.

[0071] As shown in Figures 9 and 11, the wall thickness t3 of the proximal region 20C, located closer to the proximal end (towards the proximal hub portion 90) of the image acquisition catheter 100, is greater than the wall thickness t1 of the tip region 20A. Therefore, the image acquisition catheter 100 can effectively increase the pushing force of the outer tube 20 on the proximal hub portion 90 side. In addition, the outer diameter do3 of the proximal region 20C is greater than the outer diameter do1 of the tip region 20A. Therefore, even when the wall thickness t3 of the proximal region 20C is made large, it is possible to prevent the inner diameter di3 of the proximal region 20C from becoming excessively small. This prevents obstruction of the insertion of the wiring portion 60 within the proximal region 20C. Furthermore, since the outer diameter do1 of the tip region 20A is made smaller than the outer diameter do3 of the proximal region 20C, the outer diameter near the tip portion 21 of the outer tube 20 can be made smaller, thereby improving insertability into the biological lumen.

[0072] As shown in Figures 3 and 8, the outer tube 20 is located between the base region 20C and the tip region 20A, and has an intermediate region 20B (see Figure 10) in which the wall thickness t2 and outer diameter do2 gradually decrease from the base side to the tip side.

[0073] The image acquisition catheter 100 has an intermediate region 20B where the wall thickness t2 and outer diameter do2 gradually decrease between the proximal region 20C and the tip region 20A. Therefore, the pushing force applied at the proximal region 20C (proximal hub portion 90 side) can be smoothly transmitted to the tip region 20A via the intermediate region 20B.

[0074] As shown in Figures 8 to 11, the second lumen 25 has a substantially constant inner diameter in the tip region 20A, the intermediate region 20B, and the proximal region 20C. That is, the inner diameter di1 of the tip region 20A, the inner diameter di2 of the intermediate region 20B, and the inner diameter di3 of the proximal region 20C are substantially the same size. Therefore, the image acquisition catheter 100 can secure a space corresponding to an inner diameter formed to substantially the same size along the axial direction, regardless of the relative sizes of the wall thickness and outer diameter of each region 20A, 20B, and 20C. This makes it possible to place components such as the wiring section 60 and the radiopaque marker 18 within the second lumen 25 partitioned on the outer circumference side of the inner tube 10.

[0075] In this embodiment, the range and dimensions of each region of the outer tube 20 can be defined and set as follows.

[0076] As shown in Figure 8, the tip region 20A of the outer tube 20 can be defined as any region on the base side of the tip portion 21 (a region that does not include the tip portion 21), for example, when the outer diameter of the tip portion 21 of the outer tube 20 expands toward the tip, as in this embodiment. In this case, the position of the tip of the tip region 20A (the boundary position) can be set to the position (starting point) where the expansion toward the tip of the outer tube 20 begins.

[0077] As shown in Figure 8, the base region 20C of the outer tube 20 can be constructed for any length along the axial direction from the most base position (the very base position) of the outer tube 20. The intermediate region 20B can be defined by the region located between the base of the tip region 20A and the tip of the base region 20C (the region connecting the tip region 20A and the base region 20C).

[0078] The tip region 20A can be formed, for example, with a length of 50 mm to 400 mm along the axial direction. The intermediate region 20B can be formed, for example, with a length of 100 mm to 1450 mm along the axial direction. The base region 20C can be formed, for example, with a length of 3 mm to 1350 mm along the axial direction.

[0079] The outer diameter do1 of the tip region 20A can be formed to a size of, for example, 1.7 mm to 2.3 mm. When the outer diameter do1 of the tip region 20A is formed to the above dimensions, the outer diameter do3 of the base region 20C can be formed to a size of, for example, 1.8 mm to 2.5 mm. Furthermore, when the outer diameter do1 of the tip region 20A and the outer diameter do3 of the base region 20C are formed to the above dimensions, the outer diameter do2 of the intermediate region 20B can be configured to gradually decrease from the base side to the tip side in the range of, for example, 1.7 mm to 2.5 mm.

[0080] The thickness t1 of the tip region 20A can be formed to a size of, for example, 0.05 mm to 0.35 mm. When the thickness t1 of the tip region 20A is formed to the above dimensions, the thickness t3 of the base region 20C can be formed to a size of, for example, 0.1 mm to 0.45 mm. Furthermore, when the thickness t1 of the tip region 20A and the thickness t3 of the base region 20C are formed to the above dimensions, the thickness t2 of the intermediate region 20B can be configured to gradually decrease from the base side to the tip side, for example, in the range of a maximum value (base dimension) of 0.1 mm to 0.45 mm and a minimum value (tip dimension) of 0.05 mm to 0.35 mm.

[0081] It is preferable that the rate of decrease in the outer diameter do2 of the intermediate region 20B (the rate of reduction in diameter from the base end to the tip end) and the rate of decrease in the wall thickness t2 of the intermediate region 20B (the rate of decrease from the base end to the tip end) are approximately the same. Furthermore, it is preferable that the rate of decrease in the outer diameter do2 of the intermediate region 20B and the rate of decrease in the wall thickness t2 of the intermediate region 20B are, for example, 5% to 32%.

[0082] When each part of the outer tube 20 is configured as shown in the above-mentioned dimensional examples, the inner tube 10 can be formed with, for example, an inner diameter Di of 0.90 mm to 1.10 mm, an outer diameter Do of 0.95 mm to 1.35 mm, and a wall thickness T of 0.05 mm to 0.225 mm.

[0083] The wiring section 60 of the image acquisition catheter 100 can be made of a flat cable. Furthermore, as shown in Figures 3, 8 to 11, the wiring section 60 can be arranged spirally along the outer surface of the inner tube 10. In this embodiment, the wiring section 60 is arranged spirally along the outer surface of the inner tube 10, but for example, the wiring section 60 can also be arranged linearly along the axial direction of the inner tube 10.

[0084] As shown in Figures 9 to 11, the wiring section 60, which is made of a flat cable, has a plurality of conductor sections (wire sections) 66 arranged linearly in a predetermined direction, and a covering material 65 that covers the plurality of conductor sections 66. The covering material 65 can be made of a known resin material or the like that has electrical insulating properties.

[0085] The wiring section 60 can be made of, for example, a coaxial cable. Alternatively, the wiring section 60 may be made of a flexible cable in which multiple conductor sections 66 are sandwiched between resin films or the like.

[0086] Since the wiring section 60 of the image acquisition catheter 100 is made of a flat cable, as shown in Figures 9 to 11, the space occupied by the wiring section 60 in the second lumen 25 partitioned between the inner tube 10 and the outer tube 20 (the space in the radial direction from the central axis c1 outward in a cross-sectional view perpendicular to the axis) can be reduced. In particular, since the wiring section 60 is arranged spirally so as to be wrapped around the outer surface of the inner tube 10, the wiring section 60 can be positioned to abut the outer surface of the inner tube 10. This further reduces the space occupied by the wiring section 60. As a result of the reduced space occupied by the wiring section 60, the wall thickness of each region 20A, 20B, and 20C of the outer tube 20 can be made larger. Therefore, it becomes possible to further improve the pushing force.

[0087] As shown in Figures 8 to 11, the image acquisition catheter 100 may have ring-shaped radiopaque markers 18 attached at equal intervals around the outer circumference of the inner tube 10.

[0088] Multiple radiopaque markers 18 can be arranged at regular intervals along the axial direction of the inner tube 10. The radiopaque markers 18 can be made of, for example, a known radiopaque metallic material. Examples of metallic materials that can be used as radiopaque markers 18 include Pt, Pt alloys, W, W alloys, Ag, Ag alloys, etc.

[0089] In procedures using the image acquisition catheter 100, the operator confirms a certain area on the tip side of the image acquisition catheter 100 on an X-ray image or the like. Therefore, the radiopaque marker 18 can be placed, for example, at any position in the inner tube 10 that overlaps with the tip region 20A and the intermediate region 20B located on the tip side of the image acquisition catheter 100.

[0090] The radiopaque marker 18 can be attached to the outer surface of the inner tube 10 by, for example, a ring-shaped metal part through a swaging process. The number, shape, and spacing of the radiopaque markers 18 can be appropriately set according to the specifications of the image acquisition catheter 100.

[0091] Furthermore, the radiopaque marker 18 may be placed not only on the outer surface of the inner tube 10, but also partially or entirely embedded inside the tube wall of the inner tube 10.

[0092] Furthermore, the radiopaque marker 18 can also be composed of, for example, a coil-type radiopaque marker wound in a sparse and dense manner along the outer surface of the inner tube 10. By configuring the radiopaque marker 18 in this way, the space occupied by the radiopaque marker 18 in the second lumen 25 can be reduced.

[0093] <Hand-operated hub section 90> As shown in Figures 2 and 3, the hand-operated hub section 90 has a first port 91 and a second port 92. The hand-operated hub section 90 is connected to the base ends of the inner pipe 10 and the outer pipe 20.

[0094] As shown in Figure 3, the handle hub 90 is positioned such that the base end 13 of the inner tube 10 is in communication with the outside, with the base end 13 of the inner tube 10 positioned near the base end opening of the first port 91. This allows the handle hub 90 to insert and remove the guide wire from the inner tube 10. In addition, the handle hub 90 is positioned so that the base end opening of the second port 92 is in communication with the second lumen 25 of the outer tube 20. This allows the handle hub 90 to lead out the base end of the wiring section 60 from the second port 92.

[0095] The hand-held hub section 90 can be made of, for example, a hard resin or metal material applicable in the medical field.

[0096] <External device 300> The external device 300 includes a control unit 310 and a display device 320.

[0097] The image acquisition catheter 100 can be connected to the conversion module device 130 via the cable 120. The conversion module device 130 controls the output of ultrasound transmitted from the transducer 45a of the film sensor 40, and controls the electrical signals transmitted and received between the transducer 45a and the control unit 310.

[0098] The external device 300 is electrically connected to the image acquisition catheter 100 by being connected to the image acquisition catheter 100 and the conversion module device 130 via a cable 140. This enables the external device 300 to send and receive electrical signals with the sensor unit 30 of the image acquisition catheter 100.

[0099] The control unit 310 mainly consists of a CPU, memory, and input / output unit, and is responsible for controlling the entire medical system 1. The control unit 310 outputs a control signal to cause the sensor unit 30 of the image acquisition catheter 100 to transmit ultrasound, inputs a detection signal from the sensor unit 30, and performs predetermined signal processing based on the detection signal to acquire image data (tomographic image).

[0100] The control unit 310 displays information (video) based on the acquired image data on the display device 320.

[0101] As described above, the image acquisition catheter 100 according to this embodiment is an image acquisition catheter for acquiring diagnostic ultrasound tomographic images in a biological lumen, and comprises an inner tube 10 having a first lumen 15 extending in the axial direction, a sensor section 30 positioned at the tip 11 of the inner tube 10 and having a plurality of transducers 45a arranged in a ring shape in the circumferential direction for transmitting and receiving ultrasound in a biological lumen, and an outer tube 20 positioned on the proximal end side of the sensor section 30 and covering at least a part of the inner tube 10 so as to form a second lumen 25 between the inner tube 10 and the outer tube 20, wherein the sensor section 30 comprises a film sensor 40 on which a plurality of transducers 45a are arranged and a support 50 that supports the film sensor 40, and at least a part of the film sensor 40 is sandwiched between the support 50 and the outer tube 20.

[0102] With the image acquisition catheter 100 configured as described above, at least a portion of the film sensor 40 is positioned sandwiched between the support 50 and the outer tube 20. Therefore, at least a portion of the film sensor 40 is held between the support 50 and the outer tube 20. Consequently, the bonding strength of the outer tube 20, the film sensor 40, and the support 50 can be effectively increased.

[0103] Furthermore, the image acquisition catheter 100 according to this embodiment includes an inner tube 10 having a first lumen 15 extending in the axial direction, a sensor section 30 positioned at the tip 11 of the inner tube 10 and equipped with a film sensor 40 having a plurality of transducers 45a that transmit and receive ultrasound in a biological lumen arranged in a ring shape in the circumferential direction, and an outer tube 20 positioned on the proximal end side of the sensor section 30 and covering at least a part of the inner tube 10 so as to form a second lumen 25 between itself and the inner tube 10, and the proximal end region 20C located in a certain range from the proximal end 23 toward the tip side of the outer tube 20 can be configured to have a larger wall thickness and outer diameter than the tip region 20A located in a certain range from the tip 21 toward the proximal end of the outer tube 20.

[0104] With the image acquisition catheter 100 configured as described above, the wall thickness t3 of the proximal region 20C, located closer to the proximal end (towards the proximal hub portion 90), is greater than the wall thickness t1 of the tip region 20A. This effectively increases the pushing force applied to the outer tube 20 from the proximal hub portion 90. Furthermore, since the outer diameter do3 of the proximal region 20C is greater than the outer diameter do1 of the tip region 20A, even when the wall thickness t3 of the proximal region 20C is made larger, it is possible to prevent the inner diameter di3 of the proximal region 20C from becoming excessively small. This prevents obstruction of the insertion of the wiring portion 60, etc., within the proximal region 20C. Additionally, since the outer diameter do1 of the tip region 20A is smaller than the outer diameter do3 of the proximal region 20C, the outer diameter near the tip portion 21 of the outer tube 20 can be made smaller, improving insertability into the biological lumen.

[0105] Although the image acquisition catheter according to the present invention has been described through embodiments, the present invention is not limited to the configuration described in the embodiments and can be modified as appropriate based on the claims.

[0106] For example, the outer tube does not necessarily have to have multiple regions with different outer diameters and wall thicknesses (tip region, intermediate region, and base region), and may have a configuration that, like the inner tube, has a constant outer diameter, inner diameter, and wall thickness along the axial direction.

[0107] This application is based on Japanese Patent Application No. 2024-168259 and Japanese Patent Application No. 2024-168261, both filed on September 27, 2024, the disclosures of which are incorporated herein by reference.

[0108] 1 Medical System 10 Inner tube 15 First lumen 20 Outer tube 20A Outer tube tip region 20B Outer tube middle region 20C Outer tube base region 21 Outer tube tip 25 Second lumen 30 Sensor section 40 Film sensor 41 Film sensor tip 43 Film sensor base 45a Transducer 45d Signal line 50 Support 53 Support base 53a Straight section 53b Tapered section 54 Shaft section 54a Holding space 55 Support lumen 56 Filling material 60 Wiring section 61 Wiring section tip 71 Reinforcement material 80 Tip member 90 Proximal hub section 91 First port 92 Second port 100 Image acquisition catheter 300 External device Di Inner diameter of inner tube Do Outer diameter of inner tube T, wall thickness of inner tube di1, inner diameter of tip region do1, outer diameter of tip region t1, wall thickness of tip region di2, inner diameter of intermediate region do2, outer diameter of intermediate region t2, wall thickness of intermediate region di3, inner diameter of base region do3, outer diameter of base region t3, wall thickness of base region c1, central axis

Claims

1. An imaging catheter for acquiring diagnostic ultrasound tomographic images within a biological lumen, comprising: an inner tube having a first lumen extending in the axial direction; a sensor section disposed at the tip of the inner tube, wherein a plurality of transducers for transmitting and receiving ultrasound waves within the biological lumen are arranged in a ring shape in the circumferential direction; and an outer tube disposed at a position closer to the proximal end than the sensor section so as to cover at least a portion of the inner tube, forming a second lumen between the outer tube and the outer tube, wherein the sensor section comprises a film sensor on which the plurality of transducers are arranged, and a support for supporting the film sensor, and at least a portion of the film sensor is sandwiched between the support and the outer tube.

2. The image acquisition catheter according to claim 1, wherein the base end of the support has a tapered portion whose outer diameter gradually decreases toward the base end in the axial direction, and the tip of the outer tube is fitted to the support with at least a part of the film sensor sandwiched between it and the tapered portion of the support.

3. The tip of the outer tube has a tapered shape in which the outer diameter increases toward the tip, corresponding to the tapered portion of the support, the image acquisition catheter according to claim 2.

4. The image acquisition catheter according to claim 1, having a wiring section connected to the film sensor and enabling the transmission of electrical signals between the plurality of transducers and an external device, wherein the proximal end of the film sensor is positioned proximal to the position where it is sandwiched between the support and the outer tube, and the wiring section is connected to the proximal end of the film sensor.

5. The image acquisition catheter according to claim 1, further comprising a reinforcing member that reinforces the fixation of the support and the outer tube at a position where the film sensor is sandwiched between the support and the outer tube.

6. The image acquisition catheter according to claim 1, wherein the proximal region located in a certain range from the proximal end to the proximal end of the outer tube has a greater wall thickness and outer diameter than the proximal region located in a certain range from the proximal end to the proximal end of the outer tube.

7. The image acquisition catheter according to claim 6, having an intermediate region located between the proximal region and the tip region, wherein the wall thickness and outer diameter gradually decrease from the proximal side to the tip side.

8. The image acquisition catheter according to claim 7, wherein the second lumen has a substantially constant inner diameter in the tip region, the intermediate region, and the proximal region.

9. The image acquisition catheter according to claim 6, having a wiring section connected to the film sensor and enabling the transmission of electrical signals between the plurality of transducers and an external device, wherein the wiring section is made of a flat cable and is arranged along the outer circumference of the inner tube.

10. The imaging catheter according to claim 9, comprising ring-shaped radiopaque markers attached at equal intervals to the outer surface of the inner tube, or coil-type radiopaque markers wound in a sparse and dense manner along the outer surface of the inner tube.

Images