Catheter for image acquisition

Abstract

[Problem] To provide a catheter for image acquisition, of which the passage through blood vessels is improved by shortening the length of a hard region of a tip end portion. [Solution] A catheter for image acquisition comprising: an inner tube 10; a sensor unit 30 disposed on a tip end portion of the inner tube 10, and including a plurality of transducers 32a for transmitting and receiving ultrasonic waves in a biological lumen, the plurality of transducers 32a being arranged in a ring shape in the circumferential direction; a plurality of signal lines 50 connected to the respective transducers 32a and enabling transmission of electric signals to and from an external device 300; an outer tube 20 disposed so as to define a second lumen 21 that allows the plurality of signal lines 50 to be inserted therethrough and cover the inner tube 10 at a position closer to the base end than the sensor unit 30; and a joint member 40 joining the sensor unit 30 to the inner tube 10 and the outer tube 20, wherein the joint member 40 is formed of a resin joining agent.

Description

Imaging catheter

[0001] The present invention relates to an imaging catheter.

[0002] In the treatment of lesions such as stenoses and occlusions that occur in hollow organs such as blood vessels, an imaging catheter that utilizes intravascular ultrasound (IVUS) is used as a medical device for acquiring diagnostic images in order to observe the characteristics of the lesions or the condition after treatment (see Patent Document 1).

[0003] Special Publication No. 2021-533912

[0004] In conventional imaging catheters, the distal end portion distal to the image acquisition sensor portion is formed by connecting a fusion tube made of a thermoplastic resin or the like to a flange portion extending in the longitudinal direction on the distal side of the sensor portion, and fusing the fusion tube by heat fusion or the like. Therefore, the imaging catheter has a region (hard region) at the distal end where the fusion tube has melted and hardened, the region extending over the length of the fusion tube. The distal end portion having the hard region is highly rigid and does not bend easily.

[0005] When an imaging catheter is inserted into a blood vessel, which is a lumen of the body, it advances to the target site along the shape of the blood vessel. However, because the imaging catheter has a long hard region at the tip, when passing through a small diameter blood vessel, this hard tip may get caught on the blood vessel wall, leaving room for improvement.

[0006] The present invention has been made in response to the above-mentioned problems, and specifically aims to provide an imaging catheter that can improve passability through biological lumens by shortening the longitudinal length of the hard region at the tip.

[0007] The present invention can be achieved by any one of the following means (1) to (8).

[0008] (1) An imaging catheter for acquiring diagnostic ultrasound tomographic images within a biological lumen, comprising: an inner tube with a first lumen; a sensor section disposed at the tip of the inner tube and having a plurality of transducers arranged in a ring shape circumferentially for transmitting and receiving ultrasound within the biological lumen; an outer tube disposed to cover the inner tube at a position proximal to the sensor section so as to define a second lumen; and a joint section that joins the sensor section to the inner tube and the outer tube, wherein the sensor section is composed of a shaft section extending in the longitudinal direction, a tip support section disposed at the tip of the shaft section and having a larger diameter than the outer diameter of the shaft section, a reinforcing body having a base support section disposed at the base end of the shaft section and having a larger diameter than the outer diameter of the shaft section, and a film sensor with the plurality of transducers arranged on the outer surface and wound around the reinforcing body, wherein the joint section is formed of a resin adhesive.

[0009] (2) The joint has a tapered surface in which the outer diameter decreases from the tip support portion of the sensor portion toward the outer peripheral surface of the inner tube, and has a tip joint that joins the tip support portion to the inner tube, a filling joint that fills the space between the axial portion of the reinforcement body and the wound film sensor, and a base joint that joins the base support portion of the reinforcement body to the outer tube, and the tip joint, the filling joint, and the base joint are formed with the resin bonding agent, in the imaging catheter described in (1) above.

[0010] (3) The imaging catheter according to (1) or (2) above, wherein the reinforcing body has a fixing reinforcing portion at the tip that increases the fixing strength with the joint portion.

[0011] (4) The imaging catheter according to (3) above, wherein the fixing reinforcement portion is an uneven portion formed on the distal end surface of the distal end support portion.

[0012] (5) The imaging catheter according to (3) above, wherein the fixing reinforcement portion is one or more holes formed in the distal end surface of the distal end support portion.

[0013] (6) The imaging catheter according to (3) above, wherein the fixing reinforcement portion is a tapered step portion formed on the outer peripheral surface of the outer edge of the tip of the tip support portion so as to reduce in diameter toward the inner tube.

[0014] (7) The imaging catheter according to (6) above, wherein the length of the tip joint in the longitudinal direction is 0.1 mm or more and 5 mm or less.

[0015] (8) The imaging catheter according to any one of (1) to (7) above, wherein the joint is made of an epoxy adhesive.

[0016] The imaging catheter according to the present invention can achieve the following effects.

[0017] The imaging catheter uses a resin adhesive at the joint, rather than a welding tube or other member, so that the longitudinal length of the distal joint that joins the inner tube and the distal support part of the reinforcing member can be shortened, improving the passability of the imaging catheter through biological lumens such as blood vessels.

[0018] Fig. 1 is a schematic configuration diagram of a medical system including an imaging catheter according to an embodiment. Fig. 2 is a diagram showing an imaging catheter according to an embodiment. Fig. 3 is a cross-sectional view of an imaging catheter according to an embodiment. Fig. 4 is a partial cross-sectional view of the periphery of the tip of an imaging catheter according to an embodiment. Fig. 5 is a partial cross-sectional view of the periphery of the tip of a conventional imaging catheter. Fig. 6 is a diagram showing a first form of a fixing reinforcement part of an imaging catheter according to an embodiment. Fig. 7 is a diagram showing a second form of a fixing reinforcement part of an imaging catheter according to an embodiment. Fig. 8 is a diagram showing a third form of a fixing reinforcement part of an imaging catheter according to an embodiment.

[0019] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The embodiments shown here are merely examples for embodying the technical idea of ​​the present invention and are not intended to limit the present invention. Furthermore, all other embodiments, 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 scope of the inventions set forth in the claims and their equivalents.

[0020] Furthermore, for the convenience of illustration and ease of understanding, the drawings attached to this specification may be represented schematically with the scale, aspect ratio, shape, etc. appropriately changed from the actual product, but these are merely examples and do not limit the interpretation of the present invention.

[0021] For ease of explanation, the following directions are defined in this specification. In Fig. 1, the "longitudinal direction" is the direction along the central axis of the imaging catheter 100. The "radial direction" is the direction moving away from or approaching the central axis in an orthogonal cross section (transverse cross section) with the central axis of the imaging catheter 100 as the reference axis. The "circumferential direction" is the rotational direction with the central axis of the imaging catheter 100 as the reference axis.

[0022] The side of the imaging catheter 100 where the proximal hub portion 60 is located is referred to as the "base end side." The side of the imaging catheter 100 that is located opposite the base end side and that is introduced into the living body is referred to as the "distal end side." The "distal end" refers to a portion that includes a certain range from the tip (the most distal end) toward the base end side, and the "base end" refers to a portion that includes a certain range from the base end (the most proximal end) toward the tip end side.

[0023] In this embodiment, the imaging catheter 100 is configured as an IVUS catheter that utilizes intravascular ultrasound (IVUS).

[0024] In this embodiment, a blood vessel is exemplified as a biological lumen to which the imaging catheter 100 is applied. However, the biological lumen to which the imaging catheter 100 is applied is not limited to only a blood vessel, and may be, for example, a bile duct, a trachea, an esophagus, other digestive tracts, a urethra, an ear and nose cavity, or other biological organs.

[0025] 1, the medical system 1 includes an image acquisition catheter 100 and an external device 300. The medical system 1 inserts the image acquisition catheter 100 into a patient's blood vessel, delivers the sensor unit 30 to a lesion, and outputs images (such as tomographic images of the blood vessels) captured at and around the lesion to the external device 300 for use in diagnosing the characteristics of the lesion.

[0026] <Imaging Catheter> The imaging catheter 100 has an inner tube 10, an outer tube 20, a sensor unit 30, a joint unit 40, a signal line 50, a proximal hub unit 60, and an imaging unit 70. The imaging catheter 100 is configured as a so-called "over-the-wire type catheter" in which a guide wire can be inserted and removed from the proximal end of the catheter through the first lumen 11 of the inner tube 10. However, the imaging catheter 100 may also be configured as a so-called "rapid exchange type catheter."

[0027] <Inner Tube> The inner tube 10 is a long tubular member having a first lumen 11 extending from the distal end to the proximal end, through which a guide wire can be inserted. The distal end of the inner tube 10 is located at the distal end of the imaging catheter 100, and the proximal end is located at the proximal end of the first port 61 of the proximal hub portion 60, and the inner tube 10 is configured to allow the guide wire to be inserted and removed.

[0028] The material constituting the inner tube 10 is a material that can be used in catheters, etc., 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 can be used.

[0029] <Outer Tube> The outer tube 20 is arranged to cover the inner tube 10 at a position proximal to the sensor unit 30, so as to define a second lumen 21 between the outer tube 20 and the inner tube 10, through which multiple signal lines 50 can be inserted. The proximal end of the outer tube 20 is located inside the proximal hub unit 60, distal to the distal opening of the second port 62. This allows the signal lines 50 to be inserted from the sensor unit 30 through the second lumen 21 and then led out of the second port 62. The outer tube 20 is arranged coaxially with the inner tube 10.

[0030] The outer tube 20 can be made of, for example, the same material as the inner tube 10 exemplified above.

[0031] <Sensor Unit> The sensor unit 30 is disposed at the distal end of the inner tube 10, closer to the distal end than the outer tube 20. The sensor unit 30 is composed of a reinforcing body 31 and a film sensor 32. The sensor unit 30 transmits and receives ultrasonic waves within the biological lumen, and enables transmission of electrical signals to and from an external device 300 via signal lines 50 connected to each of the transducers 32a.

[0032] The reinforcing member 31 has a cylindrical shaft portion 31a, a distal end support portion 31b disposed at the distal end of the shaft portion 31a and having a larger diameter than the outer diameter of the shaft portion 31a, and a proximal end support portion 31c disposed at the proximal end of the shaft portion 31a and having a larger diameter than the outer diameter of the shaft portion 31a. The reinforcing member 31 can be formed of a metal material. The reinforcing member 31 has a third lumen 31d formed therein, through which the inner tube 10 can be inserted.

[0033] The film sensor 32 is made of a flexible substrate on which electronic components are mounted, and an electronic circuit including a plurality of transducers 32 a etc. is formed on the outer surface. The film sensor 32 is wound around the tip support portion 31 b and the base support portion 31 c of the reinforcing body 31.

[0034] Each of the transducers 32a has an oscillator made of a piezoelectric material having piezoelectric properties, such as ceramics or quartz, capable of converting an electrical signal into ultrasonic vibrations. With the film sensor 32 wound around the reinforcing body 31, the transducers 32a form a phased array arranged in a ring shape along the circumferential direction of the reinforcing body 31. By using such a phased array type sensor, the sensor unit 30 can simultaneously acquire tomographic images of blood vessels over a wide range in the circumferential direction without rotating the sensor unit 30. There are no particular limitations on the type, arrangement, or number of the transducers 32a.

[0035] The multiple transducers 32a transmit ultrasonic waves based on an electrical signal (pulse signal) into the body cavity and receive ultrasonic waves reflected from biological tissue within the body cavity. Each transducer 32a is disposed on the outer surface of the film sensor 32 and is connected to a multiplexer 32b. The multiplexer 32b is a combination circuit that selects one of multiple input lines and connects it to a single output line. Each transducer 32a is connected to each of multiple signal lines 50 via the multiplexer 32b. Each transducer 32a is configured so that the multiplexer 32b can sequentially switch between transmission and reception. That is, the multiple transducers 32a sequentially receive each received signal and sequentially transmit the received signals via the multiplexer 32b. The multiplexer 32b is driven and controlled by a control IC 32c formed on the film sensor 32.

[0036] <Joint Section> The joint section 40 joins the sensor section 30 to the inner tube 10 and / or the outer tube 20. The joint section 40 has a distal joint section 41, a proximal joint section 42, and a filling joint section 43. The distal joint section 41, the proximal joint section 42, and the filling joint section 43 are all formed of a resin bonding agent.

[0037] The tip joint portion 41 is disposed on the tip side of the sensor portion 30 so as to be adjacent to the tip support portion 31b of the sensor portion 30 and to be in contact with the outer circumferential surface of the inner pipe 10. This allows the sensor portion 30 to be firmly joined to the inner pipe 10.

[0038] The tip joint 41 has a tapered surface 41a whose outer diameter decreases from the tip support portion 31b of the sensor unit 30 toward the outer circumferential surface of the inner tube 10. Because the tip joint 41 has the tapered surface 41a, the insertability of the imaging catheter 100 can be improved.

[0039] The base end joint portion 42 is disposed adjacent to the base end support portion 31c of the sensor portion 30 and between the sensor portion 30 and the distal end portion of the outer tube 20. This allows the sensor portion 30 to be firmly joined to the outer tube 20.

[0040] The filling joint 43 fills the internal space 33 formed between the shaft portion 31a of the reinforcing body 31 and the wound film sensor 32. This allows the film sensor 32 to be firmly joined to the reinforcing body 31. The filling joint 43 can also fill the third lumen 31d. This allows the sensor unit 30 to be firmly joined to the inner tube 10. Furthermore, by filling the third lumen 31d with the filling joint 43 so as to connect the distal joint 41 and the proximal joint 42, the joint strength of the entire joint 40 can be increased.

[0041] The resin bonding agent used for the bonding portion 40 has fluidity when applied and hardens due to a chemical change caused by a curing treatment after application. For example, a UV-curable adhesive or a thermosetting adhesive (such as an epoxy adhesive) can be suitably used as the resin bonding agent.

[0042] The resin bonding agent that constitutes the distal joint 41 partially penetrates into the interface between the reinforcing body 31 and the film sensor 32 on the distal side of the sensor unit 30. The resin bonding agent that constitutes the proximal joint 42 partially penetrates into the interface between the reinforcing body 31 and the film sensor 32 on the proximal side of the sensor unit 30. This allows the imaging catheter 100 to firmly bond the sensor unit 30 to the inner tube 10 and the outer tube 20 using only the resin bonding agent without using a fusion tube or the like, and also simplifies the manufacturing process. The distal joint 41, proximal joint 42, and filling joint 43 that constitute the joint 40 may be formed from the same resin bonding agent, or may be formed from a plurality of resin bonding agents.

[0043] In the imaging catheter 100, the tip joint 41 can be formed only from a resin bonding agent, as shown in Fig. 4A. The tip joint 41 forms a tapered surface 41a and is formed so that the tip support portion 31b and the outer circumferential surface of the inner tube 10 are bonded together.

[0044] In contrast, the configuration of the tip portion of the conventional imaging catheter 500 differs from the configuration of the tip joint portion 41. Fig. 4B shows the configuration of the periphery of the tip portion of the conventional imaging catheter 500 for comparison. As shown in Fig. 4B , the tip portion 501 of the imaging catheter 500 is provided with a flange portion 520 extending toward the tip side of the sensor portion 510, and a fusion tube 540 is attached to this flange portion 520. The imaging catheter 500 is then bonded by heat-fusing the fusion tube 540 between the tip portion of the sensor portion 510 and the outer circumferential surface of the inner tube 530. As a result, the imaging catheter 500 has a joint portion 550 formed by bonding the tip portion of the sensor portion 510 and the inner tube 530 with the fusion tube 540.

[0045] As shown in Fig. 4A , the tip joint 41 of the imaging catheter 100 of this embodiment has a length L1 in the longitudinal direction. The length L1 of the tip joint 41 in the longitudinal direction corresponds to the length of the rigid region A1 at the tip of the imaging catheter 100 that can be formed by the tip joint 41. On the other hand, the joint 550 of the conventional imaging catheter 500 has a length L2 in the longitudinal direction as shown in Fig. 4B . The length L2 of the joint 550 in the longitudinal direction corresponds to the length of the rigid region A2 at the tip of the imaging catheter 500 that can be formed by the joint 550.

[0046] As shown in Figures 4A and 4B, the length L1 of the tip joint 41 in the longitudinal direction is shorter than the length L2 of the joint 550 in the longitudinal direction (L1 < L2). The tip joint 41 is formed only from a resin adhesive, whereas the joint 550 is formed from the fusion tube 540. Because the tip joint 41 is formed from a resin adhesive, it is possible to adjust the length in the longitudinal direction to be shorter. In contrast, because the joint 550 is connected to the flange portion 520 and the fusion tube 540 is disposed therein, the length in the longitudinal direction of the joint 550 is necessarily longer by the length of the fusion tube 540 in the longitudinal direction.

[0047] As described above, the imaging catheter 100 has a tip joint 41 formed from a resin adhesive, and therefore has a shorter longitudinal length (L1<L2) than the joint 550 formed from the fusion tube 540 of the conventional imaging catheter 500. The shorter the longitudinal length L1 of the tip joint 41 of the imaging catheter 100, the shorter the longitudinal length of the hard region A1 at the tip, improving blood vessel passage. Therefore, the imaging catheter 100 has improved operability within blood vessels and can suppress blood vessel damage due to contact with the blood vessel inner wall during advancement / retraction operations.

[0048] From the viewpoint of blood vessel passageability, the length L1 of the distal joint portion 41 in the longitudinal direction is 0.1 mm or more and 5 mm or less, and preferably 0.1 mm or more and 2 mm or less.

[0049] As shown in Figures 5A to 5C, the imaging catheter 100 can be configured with a fixing reinforcement part 80 that increases the fixing strength of the tip joint part 41 to the tip support part 31b of the reinforcement body 31. The fixing reinforcement part 80 can be formed on the tip support part 31b of the reinforcement body 31, as in the first form shown in Figure 5A, the second form shown in Figure 5B, and the third form shown in Figure 5C. Note that the following forms can also be combined as appropriate.

[0050] (First Form) As shown in Fig. 5A, the fixing reinforcement part 80A according to the first form is formed by an uneven part provided on the tip surface 31e of the tip support part 31b. The uneven shape of the fixing reinforcement part 80A can increase the contact area with the tip joint part 41. By providing the fixing reinforcement part 80A, the fixing strength of the tip joint part 41 to the tip support part 31b is increased, and peeling during operation, etc. can be prevented.

[0051] (Second embodiment) As shown in Fig. 5B, the fixing reinforcement part 80B according to the second embodiment is formed by one or more holes formed in the tip surface 31e of the tip support part 31b. The contact area of ​​the fixing reinforcement part 80B with the tip joint part 41 can be increased by filling the holes with a resin adhesive. By providing the fixing reinforcement part 80B, the fixing strength of the tip joint part 41 to the tip support part 31b is increased, and peeling during operation can be prevented.

[0052] (Third Form) As shown in Fig. 5C, the fixing reinforcement part 80C according to the third form is formed as a tapered step part formed on the outer peripheral surface of the tip outer edge of the tip support part 31b so as to decrease in diameter toward the inner tube 10. The tapered shape of the fixing reinforcement part 80C increases the contact area with the tip joint part 41. By providing the fixing reinforcement part 80C, the fixing strength of the tip joint part 41 to the tip support part 31b is increased, preventing peeling during operation. Furthermore, because the fixing reinforcement part 80C has a tapered shape toward the inner tube 10, it is easy to form the tapered surface 41a when forming the tip joint part 41 with a resin adhesive.

[0053] In the fixing reinforcement part 80C of the third embodiment, the tapered step part has a length in the major axis direction of 0.1 mm to 2 mm, which allows the tip joint part 41 to be formed with a moderately tapered surface while having a short length in the major axis direction.

[0054] <Signal Line> The signal line 50 has a wire portion 51 made of a metallic material having electrical conductivity and contrast properties, one end of which is connected to the sensor unit 30 and the other end of which is connected to the connector 110. Each of the signal lines 50 is connected to the multiplexer 32b or the control IC 32c by soldering or the like. By connecting the connector 110 to the connector 330 of the external device 300, the signal line 50 becomes capable of transmitting and receiving electrical signals between the sensor unit 30 and the external device 300. The portions of the signal lines 50 exposed from the second port 62 of the proximal hub unit 60 on the base end side are bundled together to form a cable 120, which is then connected to the connector 110.

[0055] The signal line 50 can be configured with a plurality of each of a coated wire in which the wire portions 51 are coated with a fluorine-based resin or the like, and a coaxial cable in which outer and inner conductors formed by the wire portions 51 are arranged at regular concentric intervals. For example, if the signal line 50 uses a coaxial cable as a dedicated receive line, it is possible to reduce transmission loss of the electrical signal (image data) acquired by the sensor unit 30. The signal line 50 may also be configured with a flexible cable in which the wire portions 51 are sandwiched between resin films or the like, or a flat cable in which the wire portions 51 covered with an insulating coating are arranged in parallel in a band shape.

[0056] <Proximal Hub Portion> The proximal hub portion 60 has a first port 61 and a second port 62 , and is connected to the proximal ends of the inner tube 10 and the outer tube 20 .

[0057] The proximal hub section 60 is connected so that the proximal opening of the first port 61 is in communication with the first lumen 11 of the inner tube 10. This allows the proximal hub section 60 to insert and remove a guide wire into and from the inner tube 10. The proximal hub section 60 is connected so that the proximal opening of the second port 62 is in communication with the second lumen 21 of the outer tube 20. This allows the proximal ends of the multiple signal lines 50 to lead out from the second port 62 of the proximal hub section 60.

[0058] The proximal hub portion 60 can be made of, for example, a hard resin or metal material that is applicable in the medical field.

[0059] <Radiographic Section> The radiographic section 70 is disposed near the distal end of the inner tube 10. The radiographic section 70 can be made of, for example, a known metal material that is radiopaque (opaque to radio waves).

[0060] The contrast imaging units 70 can be arranged at regular intervals along the longitudinal direction of the inner tube 10 so as to function as markers when measuring the distance of the sensor unit 30 to the lesion in the blood vessel, the length of the lesion, etc. The arrangement intervals of the contrast imaging units 70 can be set, for example, between 10 mm and 40 mm.

[0061] The imaging section 70 can be a ring-shaped metal part that is radiopaque and attached to the outer circumferential surface of the inner tube 10 by swaging or the like. The imaging section 70 is not limited to being attached to the outer circumferential surface of the inner tube 10, but may also be partially or entirely embedded within the wall of the inner tube 10. The number, shape, spacing, etc. of the imaging sections 70 can be set appropriately depending on the specifications of the imaging catheter 100.

[0062] <External Device> The external device 300 includes a control unit 310 , a display device 320 , and a connector 330 .

[0063] The external device 300 is electrically connected to the imaging catheter 100 by connecting the connector 110 of the imaging catheter 100 to the connector 330. This allows the external device 300 to transmit and receive electrical signals to and from the sensor unit 30 of the imaging catheter 100.

[0064] The control unit 310 is mainly composed of a CPU, memory, and input / output units, and is responsible for controlling the entire medical system 1. The control unit 310 outputs a control signal to the sensor unit 30 of the imaging catheter 100 to emit 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).

[0065] The control unit 310 displays information (images) based on the acquired image data on the display device 320 .

[0066] As described above, the imaging catheter 100 according to this embodiment is a device for acquiring diagnostic ultrasonic tomographic images within a living body lumen, and comprises an inner tube 10 having a first lumen 11 through which a guidewire can be inserted, a sensor section 30 disposed at the distal end of the inner tube 10 and having a plurality of transducers 32a arranged in a ring shape in the circumferential direction for transmitting and receiving ultrasonic waves within the living body lumen, a plurality of signal lines 50 connected to each of the transducers 32a and enabling transmission of electrical signals between the plurality of transducers 32a and an external device 300, and a second lumen 21 through which the plurality of signal lines 50 can be inserted between the inner tube 10 and the sensor section 30. the outer tube 20 disposed on the inner tube 10; a proximal hub portion 60 connected to the proximal end of the inner tube 10 and the proximal end of the outer tube 20 and equipped with a first port 61 through which a guide wire can be inserted and removed and a second port 62 through which multiple signal lines 50 can be led out; a sensor portion 30; and a joint portion 40 joining the inner tube 10 and the outer tube 20 together. The sensor portion 30 is made up of a reinforcing body 31 having a shaft portion 31a extending in the longitudinal direction, a tip support portion 31b disposed at the tip of the shaft portion 31a and having a larger diameter than the outer diameter of the shaft portion 31a, and a base support portion 31c disposed at the base end of the shaft portion 31a and having a larger diameter than the outer diameter of the shaft portion 31a; and a film sensor 32 having multiple transducers 32a disposed on the outer surface and wound around the reinforcing body 31. The joint portion 40 is formed of a resin adhesive.

[0067] As shown in Fig. 4B, the distal end of the conventional imaging catheter 500 is joined to the sensor unit 510 using a fusion tube 540, and therefore is necessarily longer in the longitudinal direction by the longitudinal length of the fusion tube 540. In contrast, as shown in Fig. 4A, the imaging catheter 100 has a distal joint 41 that joins the inner tube 10 and the distal support portion 31b of the reinforcing member 31, which constitute the joint 40, formed of a resin adhesive, and therefore can have a shorter longitudinal length than the joint 550 (L1 < L2). Therefore, the imaging catheter 100 has improved operability within blood vessels (vascular passability) and can suppress blood vessel damage due to contact with the inner wall of the blood vessel during advancement and retraction operations.

[0068] This application is based on Japanese Patent Application No. 2023-192062, filed on November 10, 2023, the disclosure of which is incorporated herein by reference in its entirety.

[0069] 1 Medical system, 10 Inner tube, 11 First lumen, 20 Outer tube, 21 Second lumen, 30 Sensor section, 31 Reinforcement body (31a Shaft section, 31b Tip support section, 31c Base support section, 31d Third lumen, 31e Tip surface of tip support section), 32 Film sensor (32a Transducer, 32b Multiplexer, 32c Control IC), 33 Internal space, 40 Joint section, 41 Tip joint section, 42 Base joint section, 43 Filled joint section, 50 Signal line, 51 Wire section, 52 Spiral section (52a Loosely wound section, 52b, 54 Closely wound section), 53 Extension section, 55 Blade section, 60 Proximal hub section, 61 First port, 62 Second port, 70 Imaging section, 80 (80A to 80C) fixing reinforcement section, 100 imaging catheter, 110 connector of imaging catheter, 120 cable, 300 external device, 310 control unit, 320 display device, 330 connector of external device.

Claims

1. An imaging catheter for acquiring diagnostic ultrasonic tomographic images within a living body lumen, comprising: an inner tube with a first lumen; a sensor section disposed at the tip of the inner tube and having a plurality of transducers arranged in a circumferential ring shape for transmitting and receiving ultrasonic waves within the living body lumen; an outer tube disposed to cover the inner tube at a position base end side of the sensor section so as to define a second lumen; and a joint section joining the sensor section to the inner tube and the outer tube, wherein the sensor section is composed of a shaft section extending in the longitudinal direction, a reinforcing body having a tip support section disposed at the tip of the shaft section and having a diameter larger than the outer diameter of the shaft section, and a base support section disposed at the base end of the shaft section and having a diameter larger than the outer diameter of the shaft section; and a film sensor having the plurality of transducers arranged on the outer surface and wound around the reinforcing body, wherein the joint section is formed of a resin adhesive.

2. The imaging catheter described in claim 1, wherein the joint has a tapered surface in which the outer diameter decreases from the tip support portion of the sensor portion toward the outer peripheral surface of the inner tube, and comprises a tip joint that joins the tip support portion to the inner tube, a filling joint that fills the space between the shaft portion of the reinforcement body and the wound film sensor, and a base joint that joins the base support portion of the reinforcement body to the outer tube, and the tip joint, the filling joint, and the base joint are formed with the resin bonding agent.

3. An imaging catheter as described in claim 1 or 2, wherein the reinforcing body has a fixing reinforcement portion at the tip portion which enhances the fixing strength with the joint portion.

4. The imaging catheter according to claim 3, wherein the fixing reinforcement portion is an uneven portion formed on the tip surface of the tip support portion.

5. The imaging catheter according to claim 3, wherein the fixed reinforcement portion is one or more holes formed in the distal end surface of the front end support portion.

6. The imaging catheter according to claim 3, wherein the fixing reinforcement portion is a tapered step portion formed on the outer peripheral surface of the outer edge of the tip of the tip support portion so as to reduce in diameter toward the inner tube.

7. The imaging catheter according to claim 6, wherein the length of the tip joint in the longitudinal direction is 0.1 mm or more and 5 mm or less.

8. The imaging catheter according to claim 1 or 2, wherein the joint is made of an epoxy adhesive.

Images