Image acquisition catheter

Abstract

[Problem] To provide an image acquisition catheter capable of simplifying a work process when attaching, to an outer tube (first outer tube), an opaque member included in a marker having a function of measuring the length of an affected area or the like, and improving the rigidity and kink resistance of the outer tube (first outer tube) to which the opaque member is attached. [Solution] An image acquisition catheter 100 comprises: an inner tube 10 which is provided with a first lumen 15 extending in an axial direction; a sensor unit 20 which is disposed at a distal end portion 11 of the inner tube and in which a plurality of transducers 37a for transmitting and receiving ultrasonic waves are arranged annularly in a circumferential direction; a first outer tube 50 which is disposed so as to cover at least a portion of the inner tube and form a second lumen 55 between the first outer tube 50 and the inner tube; an opaque member 60 which is wound around the outer surface of the first outer tube into a coil shape and has radiopacity; and a second outer tube 70 which is disposed so as to cover the opaque member such that the opaque member is positioned between the first outer tube 50 and the second outer tube 70. The sensor unit is provided with a film sensor 30 in which a plurality of transducers 37a are arranged and with a support body 40 for supporting the film sensor. The opaque member includes a tightly wound portion 61 and a loosely wound portion 63 which are disposed at different positions in the axial direction of the first outer tube.

Description

Imaging Catheter

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

[0002] In the treatment of lesions such as stenoses or occlusions formed in biological lumens such as blood vessels, an imaging catheter using intravascular ultrasound (IVUS) is used as a medical device for acquiring diagnostic images to observe the properties of these lesions or the post-treatment state thereof (see, for example, Patent Document 1).

[0003] The imaging catheter of Patent Document 1 is configured as a phased array IVUS catheter comprising: a sensor unit (film sensor) provided with a transducer (transducer array); a support body that supports a flexible substrate; and a shaft portion having the flexible substrate and the support body disposed at a distal end portion thereof. The flexible substrate is provided with a signal line connected to a wiring portion for transmitting and receiving various electrical signals between the transducer array and an external device.

[0004] Catheter devices used for various treatments and diagnoses in vivo are sometimes provided with radiopaque markers. An operator or the like can measure the axial length of a lesion by using the radiopaque marker as a reference for axial length when the catheter device is inserted into a biological lumen such as a blood vessel.

[0005] Radiopaque markers exist in various forms. For example, a metal ring member fixed to a shaft portion by swaging or the like is sometimes used as a radiopaque marker. However, when such a radiopaque marker is employed, the fixing work of the radiopaque marker is time-consuming, which may hinder mass production of the catheter device.

[0006] For example, in the catheter device described in Patent Document 2, a radiopaque coil (wire) is wound around the inner tube. This method simplifies the manufacturing process compared to the method of fixing a metal ring member to the shaft. Furthermore, in the catheter device described in Patent Document 1, by arranging the radiopaque coil in a tightly wound or loosely wound manner around the inner tube that constitutes the shaft, the length of lesions and the like can be measured by utilizing the difference in visibility on X-ray images.

[0007] WO2020 / 038830 WO2014 / 031854

[0008] In phased array IVUS catheters, the shaft is constructed as a multi-tube structure with an inner tube and an outer tube, and the wiring section connected to the film sensor is sometimes placed in a lumen partitioned between the inner and outer tubes. In IVUS catheters, if a structure is adopted in which a radiopaque coil is wound around the inner tube, the wiring section may interfere with the coil when passing the wiring section through the lumen, potentially causing the coil to shift position. To avoid this problem, it is conceivable to fix the coil to the inner tube using adhesive, but if adhesive is used, the thickness of the adhesive will fill the gap in the lumen, making it difficult to insert the wiring section into the lumen and leading to complicated manufacturing work.

[0009] Furthermore, when arranging the wiring and coil within the lumen formed between the inner and outer tubes, a relatively small diameter coil must be selected to match the size of the lumen. As a result, it becomes difficult to improve the rigidity and kink resistance of the shaft by using a coil that is radiopaque.

[0010] The present invention has been made based on the above problems, and aims to provide an image acquisition catheter that can simplify the work of attaching an opaque member constituting a marker with a function for measuring the axial length of a lesion or the like to an outer tube (first outer tube), and can improve the rigidity and kink resistance of the outer tube (first outer tube) to which the opaque member is attached.

[0011] The present invention can be achieved by any one of the means described in (1) to (9) below.

[0012] (1) An image acquisition catheter 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 ultrasonic waves are arranged in a ring shape in the circumferential direction; a first outer tube disposed to cover at least a part of the inner tube so as to form a second lumen between itself and the inner tube; an opaque member having X-ray opacity, wound in a coil shape around the outer surface of the first outer tube; and a second outer tube disposed to cover the opaque member between itself and the first 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 the opaque member includes a tightly wound portion and a loosely wound portion disposed at different positions in the axial direction of the first outer tube.

[0013] (2) The image acquisition catheter according to (1), wherein the tip and proximal end of the second outer tube are bonded or welded to the first outer tube.

[0014] (3) The image acquisition catheter according to (2), wherein the tip of the first outer tube is connected to the support at a position closer to the tip of the second outer tube, and the tip of the second outer tube is located closer to the proximal end than the connection point where the first outer tube and the support are connected.

[0015] (4) The tip of the second outer tube is bonded to the first outer tube by a tip-side adhesive portion, and the tip-side adhesive portion has a tapered shape in which the outer diameter decreases toward the tip, as described in (3).

[0016] (5) The tip of the second outer tube is positioned further forward than the tip of the first outer tube, and the loosely wound portion is positioned radially outward of the connection portion where the inner tube and the support are connected in the impermeable member, as described in (1) or (2).

[0017] (6) The image acquisition catheter according to any one of (1) to (5), wherein the tip of either the first outer tube or the second outer tube is positioned radially outward on the proximal end side of the film sensor, and the tip of the other is provided on the proximal end side of the film sensor.

[0018] (7) The image acquisition catheter according to any one of (1) to (6), wherein the second outer tube extends to the proximal end of the first outer tube, and the impermeable member includes a first section in which the tightly wound portion is formed over a first axial length, and a second section in which the tightly wound portion is formed over a second axial length longer than the first axial length, and the second section is formed over a predetermined range from the proximal end of the first outer tube toward the tip.

[0019] (8) The image acquisition catheter according to any one of (1) to (7), wherein the tightly wound portions and the loosely wound portions are arranged alternately in the axial direction, and the tightly wound portions are formed at equal intervals in the axial direction.

[0020] (9) The image acquisition catheter according to any one of (1) to (8), wherein the tightly wound portions and the loosely wound portions are arranged alternately in the axial direction, and the tightly wound portions comprise a tip-side region formed at equal intervals in the axial direction and a proximal-side region where the intervals between the tightly wound portions are not arranged at equal intervals, and the intervals between the tightly wound portions become smaller as the proximal-side region approaches the bending center.

[0021] The present invention provides an image acquisition catheter that simplifies the process of attaching an X-ray opaque marker, which has a function for measuring the axial length of a lesion or the like, to the outer tube (first outer tube), and improves the rigidity and kink resistance of the outer tube (first outer tube) to which the X-ray opaque marker is attached.

[0022] 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 an enlarged cross-sectional view of the area near the tip 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 an enlarged cross-sectional view of the area near the proximal end of the image acquisition catheter according to an embodiment. This is an enlarged cross-sectional view of a part of an image acquisition catheter according to a modified example. This is an enlarged cross-sectional view of the area near the proximal end of an image acquisition catheter according to a modified example. This is a diagram illustrating an image acquisition catheter according to another modified example 1. This is a diagram illustrating an image acquisition catheter according to another modified example 2.

[0023] 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.

[0024] 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.

[0025] For the sake of clarity, the following directions are defined in this specification.

[0026] In each figure, the "axial direction" is defined as 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. The "radial direction" is the direction of approaching and moving away from the central axis c1 (radial direction).

[0027] Furthermore, the arrows X1-X2 shown in each figure indicate the axial direction of the image acquisition catheter 100, and the arrows Z1-Z2 indicate the height direction perpendicular to the axial direction.

[0028] In the image acquisition catheter 100, the side where the proximal hub portion 95 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 (frontmost point) 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.

[0029] Figures 1 and 2 schematically show the overall configuration of the medical system 1 and the image acquisition catheter 100 according to this embodiment. Figures 3 to 6 show cross-sections of each part of the image acquisition catheter 100 in the axial direction.

[0030] In this embodiment, the image acquisition catheter 100 is configured as an IVUS catheter utilizing intravascular ultrasound diagnostics.

[0031] Examples of biological lumens to which the image acquisition catheter 100 can be applied include blood vessels. However, the biological lumens to which the image acquisition catheter 100 can be applied are not limited to blood vessels, but may also include other biological organs such as the bile duct, trachea, esophagus, other digestive tract organs, urethra, ear, nose, and throat lumen, etc.

[0032] <Medical System 1> As shown in Figure 1, the medical system 1 includes an image acquisition catheter 100 and an external device 300.

[0033] Medical system 1 is used to diagnose the characteristics of a lesion by inserting an image acquisition catheter 100 into the patient's blood vessel to deliver the sensor unit 20 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.

[0034] <Image Acquisition Catheter 100> Referring to Figures 1 to 6, the image acquisition catheter 100 comprises an inner tube 10 having a first lumen 15 extending in the axial direction, a sensor section 20 located at the tip 11 of the inner tube 10 and having a plurality of transducers 37a for transmitting and receiving ultrasonic waves arranged in a ring shape in the circumferential direction, a first outer tube 50 (inner layer) positioned to cover at least a part of the inner tube 10 so as to form a second lumen 55 between it and the inner tube 10, an opaque member 60 having X-ray opacity wound in a coil shape (spirally) around the outer surface of the first outer tube 50, and a second outer tube 70 (outer layer) positioned between it and the first outer tube 50 so as to cover the opaque member 60.

[0035] 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 95a of the proximal hub portion 95 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."

[0036] <Inner tube 10> As shown in Figure 3, the inner tube 10 can be made up of a long tubular member having a first lumen 15 that extends from the tip 11 to the base 13.

[0037] A guidewire can be inserted through the first lumen 15 to guide the movement of the imaging catheter 100 within the biological lumen.

[0038] As shown in Figure 4, 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 (see Figure 3) for guiding the guidewire, which has been inserted into the first lumen 15, to the proximal end of the image acquisition catheter 100.

[0039] The constituent material of the inner tube 10 is a material applicable to known catheters and the like. For example, various thermoplastic elastomers such as styrene-based, polyolefin-based, polyurethane-based, polyester-based, polyamide-based, polyimide-based, polybutadiene-based, transpolyisoprene-based, fluororubber-based, and chlorinated polyethylene-based materials can be used.

[0040] As shown in FIG. 4, a distal end member 90 (distal tip) can be attached near the distal end portion 11 of the inner tube 10. The distal end member 90 can be formed of, for example, a resin member having relatively high flexibility. The distal end member 90 can be joined (fixed) to the support body 40 included in the sensor unit 20 by, for example, a joining portion 90a.

[0041] The distal end member 90 can be configured to have a tapered portion whose outer diameter gradually decreases toward the distal end side. Thereby, the image acquisition catheter 100 can have improved insertability into a living body lumen.

[0042] <Sensor Unit 20> As shown in FIGS. 2 to 4, the sensor unit 20 includes a film sensor 30 on which a plurality of transducers 37a are arranged, and a support body 40 that supports the film sensor 30.

[0043] <Film Sensor 30> The film sensor 30 can be formed of a flexible substrate having electronic components mounted on a film substrate. An electronic circuit including a plurality of transducers 37a and the like is formed on a surface of the film sensor 30.

[0044] As shown in FIG. 4, a cylindrical portion 35 shaped by winding a flat main body portion in the circumferential direction is formed in a part of the film sensor 30. The film sensor 30 is supported by the support body 40 in a state where the cylindrical portion 35 is formed.

[0045] The cylindrical portion 35 is arranged coaxially with the inner tube 10 and the respective outer tubes 50 and 70 (on the same central axis c1). The cylindrical portion 35 can be configured to have, for example, a cylindrical shape provided with a substantially circular cross-section orthogonal to the axis.

[0046] As shown in FIG. 4, the film sensor 30 includes an extending portion 36 extending from the cylindrical portion 35 toward the proximal end side. The extending portion 36 extends from the proximal end of the cylindrical portion 35 toward the proximal end side, and is disposed only on a part in the circumferential direction around the central axis c1. A part of the extending portion 36 and the proximal end portion 33 located on the proximal end side relative to the extending portion 36 can be disposed in the second lumen 55.

[0047] The film sensor 30 may be configured to include a rib portion 35a disposed so as to cover at least a part of the connection position P1 between the proximal end portion 43 of the support body 40 and the distal end portion 51 of the first outer tube 50 on the radially outer side.

[0048] The rib portion 35a may be formed as a part of the cylindrical portion 35 of the film sensor 30. In the present embodiment, the rib portion 35a is located on the proximal end side relative to the proximal-side protruding portion 44b of the support body 40 in the cylindrical portion 35, and is formed of a portion that radially overlaps at least a part of the proximal end portion 43 of the support body 40 and the distal end portion 51 of the first outer tube 50.

[0049] When the vicinity of the distal end portion 51 of the first outer tube 50 passes through a bent portion or the like of a biological lumen, the rib portion 35a restricts the movement of the distal end portion 51 of the first outer tube 50 on the radially outer side, and suppresses excessive movement of the distal end portion 51 of the first outer tube 50 in a direction away from the support body 40. Therefore, the image acquisition catheter 100 can prevent the distal end portion 51 of the first outer tube 50 from breaking near the connection position P1.

[0050] There are no particular restrictions on the shape of the axial orthogonal cross-section, the axial length, or the like of the rib portion 35a. Further, the film sensor 30 may not be provided with the rib portion 35a.

[0051] Each transducer 37a arranged on the film sensor 30 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. The transducers 37a form a phased array, arranged in a ring shape along the circumferential direction of the support 40, with a portion of the film sensor 30 wound around the support 40. By equipping the image acquisition catheter 100 with a phased array type sensor configured as described above, tomographic images of blood vessels can be acquired simultaneously over a wide area in the circumferential direction without rotating the sensor unit 20. There are no particular restrictions on the type, arrangement, or number of transducers 37a.

[0052] Multiple transducers 37a 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 37a is positioned on the surface of the film sensor 30 and is connected to the multiplexer 37b.

[0053] The multiplexer 37b is a combination circuit that selects one of several input lines and connects it to a single output line. Each transducer 37a is connected to each of the multiple signal lines 37d formed on the film sensor 30 via the multiplexer 37b. Each transducer 37a is configured to sequentially switch between transmit and receive operations by the multiplexer 37b. In other words, the multiple transducers 37a sequentially receive each received signal and sequentially transmit the received signals via the multiplexer 37b. The multiplexer 37b is driven and controlled by a control IC 37c formed on the film sensor 30.

[0054] The signal line 37d formed on the film sensor 30 extends to the vicinity of the base end 33 of the film sensor 30.

[0055] The image acquisition catheter 100 is connected to the film sensor 30 and has a wiring section 98 that enables the transmission of electrical signals between a plurality of transducers 37a and an external device 300.

[0056] The base end 33 of the film sensor 30 can be connected to the tip 98a of the wiring section 98 by soldering or the like, while the signal line 37d and the conductor portion (not shown) of the wiring section 98 are electrically connected.

[0057] The sensor unit 20 can send and receive various signals to and from the control unit 310 of the external device 300 via the signal line 37d and the wiring unit 98.

[0058] The film sensor 30 can be made of, for example, a material such as polyimide processed into a sheet.

[0059] <Support 40> As shown in Figures 4 and 5, the support 40 has a tip portion 41, a base portion 43, a shaft portion 44 extending between the tip portion 41 and the base portion 43, a lumen 45 that connects the tip portion 41 and the base portion 43 and through which the inner tube 10 is inserted, a tip-side projection 44a provided near the tip of the shaft portion 44 and projecting in a direction perpendicular to the axial direction, and a base-side projection 44b provided near the base of the shaft portion 44 and projecting in a direction perpendicular to the axial direction.

[0060] As shown in Figure 4, the tip member 90 can be fixed to the tip portion 41 of the support 40. There are no particular restrictions on the specific position or range for fixing the tip member 90 to the support 40, but for example, any location near the tip portion 41 and the tip-side protrusion 44a can be selected.

[0061] As shown in Figures 4 and 5, the film sensor 30 is wrapped around the outer circumferential surface of the tip-side projection 44a and the outer circumferential surface of the base-side projection 44b. The tip portion 31 of the film sensor 30 is joined to the tip member 90 by a joining portion 90a.

[0062] A filler material 46 is filled in the space partitioned between the film sensor 30 and the shaft portion 44. The filler material 46 can be made of, for example, a resin component obtained by curing a resin bonding material (adhesive, etc.). The bonding force between the film sensor 30 and the support 40 is increased via the filler material 46.

[0063] The support 40 can be made of a metal material, either partially or entirely. Examples of metal materials include SUS (stainless steel). Alternatively, the support 40 can be made of a resin tube coated with a metal such as gold. Furthermore, the support 40 can be made of a material that is harder (more rigid) than the film sensor 30, the inner tube 10, and the outer tubes 50 and 70. This allows the support 40 to firmly support the film sensor 30.

[0064] In the image acquisition catheter 100, the filler 46 used for joining members and reinforcing joint strength, the tip-side adhesive portion 81, the proximal-side adhesive portion 83, the connecting portion 85, and the joint portion 90a can each be made of, for example, a resin-based adhesive material. As the resin-based adhesive material, 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.).

[0065] <First outer tube 50, second outer tube 70> As shown in Figures 4 and 5, the first outer tube 50 is positioned to cover a part of the inner tube 10.

[0066] A wiring section 98 can be inserted through the second lumen 55 formed between the first outer tube 50 and the inner tube 10.

[0067] As shown in Figure 4, the tip portion 51 of the first outer tube 50 can be configured to have a cut surface (inclined surface) that is cut at an angle with respect to the axial direction.

[0068] The portion of the first outer tube 50 that extends from the tip 51 toward the base end can be formed into a tubular shape with a substantially circular cross-section. The first outer tube 50 may also be configured without cut surfaces, having a continuous substantially circular cross-sectional shape along the axial direction.

[0069] The second outer tube 70 is positioned to cover the portion of the first outer tube 50 that is located closer to the base end than the tip end 51.

[0070] A accommodating section 75 (space) for arranging the impermeable member 60 is formed between the first outer tube 50 and the second outer tube 70. The accommodating section 75 extends continuously from near the tip 51 of the first outer tube 50 to near the base end 53 of the first outer tube 50.

[0071] The first outer tube 50 and the second outer tube 70 are arranged coaxially with the inner tube 10. The first outer tube 50 and the second outer tube 70 can be made of the same materials as those exemplified above as the constituent materials of the inner tube 10.

[0072] As shown in Figures 4 and 5, the impermeable member 60 includes a tightly wound portion 61 and a loosely wound portion 63 arranged at different axial positions of the first outer tube 50.

[0073] The impermeable member 60 is held to the first outer tube 50 in a state in which it is wound in a coil shape around the outer surface of the first outer tube 50.

[0074] The opaque member 60 can be made of, for example, a wire with a circular cross-section perpendicular to its axis (round wire) or a wire with a rectangular cross-section perpendicular to its axis (ribbon wire). In this embodiment, the opaque member 60 is made of a wire with a circular cross-section. However, there are no particular restrictions on the cross-sectional shape, thickness, cross-sectional area, etc., of the opaque member 60.

[0075] The tightly wound portion 61 of the impermeable member 60 is a portion that is tightly wound along the axial direction of the first outer tube 50. The loosely wound portion 63 is a portion that is loosely wound along the axial direction of the first outer tube 50. In the tightly wound portion, as shown in the axial cross-section in Figures 4 and 5, the spacing between the wires in the portion wound around the outer surface of the first outer tube 50 is small (a portion with a large number of turns of the impermeable member 60 per predetermined length in the axial direction). In the loosely wound portion 63, as shown in the axial cross-section in Figures 4 and 5, the spacing between the wires in the portion wound around the outer surface of the first outer tube 50 is smaller than that of the tightly wound portion 61 (a portion with a small number of turns of the impermeable member 60 per predetermined length in the axial direction).

[0076] In this embodiment, the tightly wound portion 61 is composed of a portion in which an impermeable member 60 is tightly wound in a coil shape on the outer surface of the first outer tube 50 so that no gaps are formed in the axial direction. The loosely wound portion 63 is composed of a portion in which an impermeable member 60 is loosely wound in a coil shape on the outer surface of the first outer tube 50 so that a gap of a predetermined size is formed in the axial direction.

[0077] The opaque member 60 can be made of, for example, a known metallic material that is opaque to X-rays. Examples of such metallic materials include Pt, Pt alloys, W, W alloys, Ag, Ag alloys, and the like.

[0078] The image acquisition catheter 100 is positioned between the first outer tube 50 and the second outer tube 70 and has an impermeable member 60 with a tightly wound portion 61 and a loosely wound portion 63, thereby exhibiting the following effects.

[0079] In the image acquisition catheter 100, the wiring portion 98 connected to the film sensor 30 is inserted through a second lumen 55 formed between the inner tube 10 and the first outer tube 50. On the other hand, the impermeable member 60 is located in a housing portion 75 formed between the first outer tube 50 and the second outer tube 70. Therefore, when passing the wiring portion 98 from the tip end to the proximal end of the inner tube 10, interference between the wiring portion 98 and the impermeable member 60 can be prevented. This prevents misalignment of the impermeable member 60 located in the housing portion 75 when performing the above operation.

[0080] Furthermore, for example, when inserting the wiring section 98 and the opaque member 60 into the second lumen 55 formed between the inner tube 10 and the first outer tube 50, it is necessary to select an opaque member 60 having an outer diameter and cross-sectional shape that can be inserted into the second lumen 55, corresponding to the thickness and cross-sectional shape of the wiring section 98. In this case, it becomes necessary to use an opaque member (wire) with a relatively small diameter to match the size of the second lumen 55. In contrast, in this embodiment, the opaque member 60 is arranged in a housing section 75 provided separately from the second lumen 55. Therefore, it becomes possible to use an opaque member 60 with a larger outer diameter and cross-sectional shape. This makes it possible to improve the rigidity and kink resistance of the first outer tube 50 around which the opaque member 60 is wrapped.

[0081] Furthermore, since the marker portion made of the radiopaque member 60 has a tightly wound portion 61 and a loosely wound portion 63, the operator can clearly distinguish between the tightly wound portion 61 and the portion other than the tightly wound portion 61 on the X-ray fluoroscopic image acquired during a procedure using the image acquisition catheter 100. By confirming the tightly wound portion 61 on the X-ray fluoroscopic image, the operator can easily grasp the position of the tip of the image acquisition catheter 100. In addition, by using the length or number of tightly wound portions 61 as a reference for the axial length, the operator can easily grasp the axial length of the lesion.

[0082] As shown in Figures 5 and 6, the tip 71 and base 73 of the second outer tube 70 can be bonded or welded to the first outer tube 50. In this embodiment, the tip 71 and base 73 of the second outer tube 70 are each bonded to the first outer tube 50.

[0083] By bonding or fusing the parts 71 and 73 of the second outer tube 70 to the first outer tube 50, the rigidity and kink resistance of the first outer tube 50 and the second outer tube 70 can be improved. Furthermore, by fixing the parts 71 and 73 of the second outer tube 70 to the first outer tube 50, the housing portion 75 formed between the second outer tube 70 and the first outer tube 50 can be closed at the axial end and base positions. This prevents the impermeable member 60 from falling out or flying out of the housing portion 75.

[0084] As shown in Figure 4, the tip 51 of the first outer tube 50 is connected to the support 40 at a position closer to the tip than the tip 71 of the second outer tube 70. Also, the tip 71 of the second outer tube 70 is located closer to the base end than the connection portion 85 to which the first outer tube 50 and the support 40 are connected.

[0085] The support 40, the inner tube 10, and the tip 51 of the first outer tube 50 are connected to each other via a connecting portion 85 that is positioned over a predetermined range from near the base end 43 of the support 40 toward the base end.

[0086] In this embodiment, the tip portion 71 of the second outer tube 70 is connected to the first outer tube 50 at a position closer to the proximal end than the connection portion 85. In other words, the second outer tube 70 is not located at the connection portion 85. Therefore, the image acquisition catheter 100 can reduce the rigidity near the connection portion 85 compared to the case where the second outer tube 70 is located at the connection portion 85. As a result, when the image acquisition catheter 100 passes through a bend in the biological lumen, etc., fracture of the support 40, inner tube 10, and first outer tube 50 near the connection portion 85 can be prevented more effectively. In addition, since the second outer tube 70 is not located at the connection portion 85, the outer diameter of the image acquisition catheter 100 at the connection portion 85 can be reduced compared to the case where the second outer tube 70 is located at the connection portion 85, thus reducing the impact on passage through stenosis.

[0087] As shown in Figures 4 and 5, the tip portion 71 of the second outer tube 70 is bonded to the first outer tube 50 by the tip-side adhesive portion 81.

[0088] The tip-side adhesive portion 81 can be configured to have a tapered shape, with its outer diameter decreasing towards the tip. By configuring the tip-side adhesive portion 81 in this way, it is possible to prevent the formation of a radial step near the tip portion 71 of the second outer tube 70. Therefore, the image acquisition catheter 100 can be prevented from being hindered from moving smoothly by the tip-side adhesive portion 81 catching on the blood vessel wall or the like.

[0089] Furthermore, the base end adhesive portion 83 that bonds the base end portion 73 of the second outer tube 70 to the base end portion 53 of the first outer tube 50 can be provided at any position near each base end portion 73, 53 so as not to obstruct the insertion of the wiring portion 98 inside the second lumen 55 (see Figure 6).

[0090] As shown in Figures 5 and 6, the second outer tube 70 extends to the base end 53 of the first outer tube 50.

[0091] The impermeable member 60 includes a first section 60A in which a tightly wound portion 61 is formed over a first axial length L1, and a second section 60B in which a tightly wound portion 61 is formed over a second axial length L2 which is longer than the first axial length L1.

[0092] As shown in Figure 6, the second section 60B can be formed over a predetermined range extending from the base end 53 of the first outer tube 50 toward the tip.

[0093] In procedures using the image acquisition catheter 100, the operator can use the tightly wound portion 61B (tightly wound portion 61) located in the second section 60B as a depth marker to confirm the insertion depth of the image acquisition catheter 100 into the biological lumen. Furthermore, since the first axial length L1 of the tightly wound portion 61A (tightly wound portion 61) located in the first section 60A is shorter than the second axial length L2 of the tightly wound portion 61B located in the second section 60B, the operator can use the tightly wound portion 61A as a reference for axial length when the tip of the image acquisition catheter 100 is positioned in the biological lumen, thereby enabling more accurate measurement of the axial length of the lesion present in the biological lumen.

[0094] Furthermore, when using the tightly wound portion 61B located in the second section 60B as a depth marker as described above, it is preferable that the portion of the second outer tube 70 and / or the hand hub portion 95 that overlaps with the position where the tightly wound portion 61B is located be made transparent or semi-transparent in order to make the tightly wound portion 61B visible from the outside.

[0095] As shown in Figures 5 and 6, the tightly wound sections 61 and the loosely wound sections 63 can be arranged alternately in the axial direction. Furthermore, the tightly wound sections 61 can be formed at equal intervals in the axial direction.

[0096] As described above, by arranging the tightly wound portions 61 and loosely wound portions 63 alternately in the axial direction, it becomes possible to uniformly increase the rigidity of the first outer tube 50 on which the impermeable member 60 is placed along the axial direction. Furthermore, by forming the tightly wound portions 61 at equal intervals in the axial direction, it is possible to prevent the rigidity of a part of the first outer tube 50 in the axial direction from becoming extremely high. This effectively prevents kinks and the like from occurring in the second outer tube 70.

[0097] The following describes examples of the dimensions of each part of the image acquisition catheter 100. Note that the dimensions of each part of the image acquisition catheter 100 according to this embodiment are not limited to those described below.

[0098] The first section 60A can be formed, for example, in a range of 10 mm to 500 mm from the tip to the base end of the first outer tube 50. When the first section 60A is arranged in this way, the second section 60B can be formed, for example, in a range of 300 mm to 1000 mm from the base end to the tip end of the first outer tube 50.

[0099] The first axial length L1 of the tightly wound portion 61A located in the first section 60A can be formed to be, for example, 0.5 mm to 5 mm. When the tightly wound portion 61A is configured in this way, the second axial length L2 of the tightly wound portion 61B located in the second section 60B can be formed to be, for example, 3 mm to 50 mm.

[0100] The axial length L3 of the loosely wound portion 63 can be formed to be, for example, 0.05 mm to 0.3 mm.

[0101] The axial spacing Ls1 of the tightly wound portions 61 can be formed to be, for example, 2.5 mm to 50 mm. The above axial spacing Ls1 can be defined as the distance between the axial center positions of adjacent tightly wound portions 61 in the axial direction. The axial spacing Ls1 of the tightly wound portions 61 can be formed to be the same size in the first section 60A and the second section 60B.

[0102] The axial spacing Ls2 of the loosely wound portions 63 can be formed to be, for example, 0.1 mm to 5 mm. The above axial spacing Ls2 can be defined as the distance between the axial center positions of adjacent loosely wound portions 63 in the axial direction.

[0103] <Hand hub section 95> The hand hub section 95 has a first port 95a and a second port 95b. The hand hub section 95 is connected to the base end 13 of the inner pipe 10 and the base ends 53 and 73 of the outer pipes 50 and 70.

[0104] The handle hub section 95 is connected to the base end opening (not shown) of the first port 95a and the first lumen 15 of the inner tube 10. This allows the handle hub section 95 to insert and remove the guide wire from the inner tube 10.

[0105] The hand-held hub section 95 is connected to the base end opening (not shown) of the second port 95b and the second lumen 55 of the first outer tube 50 in communication. This allows the hand-held hub section 95 to lead out the base end of the wiring section 98 from the second port 95b.

[0106] The hand-held hub portion 95 can be made of, for example, a hard resin or metal material applicable in the medical field.

[0107] <External device 300> As shown in Figure 1, the external device 300 includes a control unit 310 and a display device 320.

[0108] 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 37a of the film sensor 30, and controls the electrical signals transmitted and received between the transducer 37a and the control unit 310.

[0109] 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 20 of the image acquisition catheter 100.

[0110] 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 20 of the image acquisition catheter 100 to transmit ultrasound, receives a detection signal from the sensor unit 20, and performs predetermined signal processing based on the detection signal to acquire image data (tomographic image).

[0111] The control unit 310 displays information (video) based on the acquired image data on the display device 320.

[0112] As described above, 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 20 disposed at the tip 11 of the inner tube 10 and having a plurality of transducers 37a for transmitting and receiving ultrasonic waves arranged in a ring shape in the circumferential direction, a first outer tube 50 disposed to cover at least a part of the inner tube 10 so as to form a second lumen 55 between it and the inner tube 10, an opaque member 60 having X-ray opacity wound in a coil shape around the outer surface of the first outer tube 50, and a second outer tube 70 disposed to cover the opaque member 60 between it and the first outer tube 50. The sensor section 20 includes a film sensor 30 on which a plurality of transducers 37a are arranged, and a support 40 that supports the film sensor 30. The opaque member 60 includes a tightly wound portion 61 and a loosely wound portion 63 disposed at different positions in the axial direction of the first outer tube 50.

[0113] In the image acquisition catheter 100, the wiring section 98 connected to the film sensor 30 is inserted through a second lumen 55 formed between the inner tube 10 and the first outer tube 50. On the other hand, the impermeable member 60 is positioned in a housing section 75 (space) formed between the first outer tube 50 and the second outer tube 70. Therefore, when passing the wiring section 98 from the tip end to the base end of the inner tube 10, interference between the wiring section 98 and the impermeable member 60 can be prevented. This prevents misalignment of the impermeable member 60 positioned in the housing section 75 during the above operation.

[0114] Furthermore, in the image acquisition catheter 100, the radiopaque member 60 is placed in a housing section 75, which is provided separately from the second lumen 55. Therefore, it becomes possible to use a radiopaque member 60 with a larger outer diameter and cross-sectional shape without being limited by the size of the second lumen 55. This makes it possible to improve the rigidity and kink resistance of the first outer tube 50 around which the radiopaque member 60 is wrapped.

[0115] Furthermore, since the marker portion made of the radiopaque member 60 has a tightly wound portion 61 and a loosely wound portion 63, the operator can clearly distinguish between the tightly wound portion 61 and the other portion on the X-ray fluoroscopic image acquired during a procedure using the image acquisition catheter 100. By confirming the tightly wound portion 61 on the X-ray fluoroscopic image, the operator can easily determine the position of the tip of the image acquisition catheter 100. In addition, by using the tightly wound portion 61 as a reference for axial length, the operator can easily measure the axial length of the lesion.

[0116] <Examples of Modifications> Next, we will describe examples of modifications to the embodiments described above. In describing the examples of modifications, explanations of the components and contents already described will be omitted as appropriate.

[0117] Figure 7 shows a cross-sectional view of the tip of the modified image acquisition catheter 100. Figure 8 shows a cross-sectional view of the proximal end of the modified image acquisition catheter 100.

[0118] In the embodiment described above, the tip 51 of the first outer tube 50 is connected to the support 40 at a position closer to the tip than the tip 71 of the second outer tube 70, and the tip 71 of the second outer tube 70 is configured to be located closer to the base end than the connection portion 85 to which the first outer tube 50 and the support 40 are connected (see Figure 4).

[0119] In this modified example, as shown in Figure 7, the tip 71 of the second outer tube 70 is positioned further forward than the tip 51 of the first outer tube 50. Furthermore, the tip 71 of the second outer tube 70, which is positioned further forward than the tip 51 of the first outer tube 50, is connected at the connection portion 85 to the base end 43 of the support 40, the inner tube 10, and the tip 71 of the second outer tube 70, respectively.

[0120] As shown in Figure 7, in the impermeable member 60, a loosely wound portion 63 is arranged on the radially outer side of the connection portion 85 where the inner tube 10 and the support body 40 are connected.

[0121] In this modified image acquisition catheter 100, similar to the embodiment described above, the radiopaque member 60 is positioned in a housing portion 75 (space) formed between the first outer tube 50 and the second outer tube 70. Therefore, when passing the wiring portion 98 from the tip end to the proximal end of the inner tube 10, interference between the wiring portion 98 and the radiopaque member 60 can be prevented. Also, similar to the embodiment described above, it becomes possible to use a radiopaque member 60 with a larger outer diameter and cross-sectional shape, thereby improving the rigidity and kink resistance of the first outer tube 50 around which the radiopaque member 60 is wrapped. Furthermore, similar to the embodiment described above, by using the radiopaque member 60 as a marker portion, it becomes possible to easily determine the axial length of the lesion.

[0122] Furthermore, a loosely wound portion 63 of the impermeable member 60 is arranged at the connection portion 85. Therefore, compared to the case where a tightly wound portion 61 is arranged at the connection portion 85, it is possible to reduce the rigidity near the connection portion 85. As a result, when the image acquisition catheter 100 passes through a bend in the biological lumen, it is possible to effectively prevent the support 40, inner tube 10, first outer tube 50, and second outer tube 70 from breaking near the connection portion 85.

[0123] In the modified image acquisition catheter 100, as shown in Figure 8, the proximal ends 53 and 73 of each outer tube 50 and 70 are fixed together (for example, by bonding or fusing), thereby, similar to the embodiment described above, the housing portion 75 formed between the first outer tube 50 and the second outer tube 70 can be closed at the axial tip and proximal end positions. This prevents the impermeable member 60 from falling out or flying out from between the first outer tube 50 and the second outer tube 70.

[0124] In the modified example, the tip portion 71 of the second outer tube 70 is configured to have a cut surface (inclined surface) that is cut obliquely with respect to the axial direction. However, the second outer tube 70 may also be configured to have a substantially circular cross-sectional shape that continues along the axial direction.

[0125] <Another Modification Example 1> In the image acquisition catheter, for example, the tip of either the first outer tube 50 or the second outer tube 70 can be positioned radially outward from the proximal end of the film sensor 30, and the tip of the other can be positioned proximal to the film sensor 30. Figure 9(A) shows a simplified diagram when the tip 51 of the first outer tube 50 is positioned proximal to the tip 71 of the second outer tube 70, and Figure 9(B) shows a simplified diagram when the tip 71 of the second outer tube 70 is positioned proximal to the tip 51 of the first outer tube 50.

[0126] When the arrangement shown in Figures 9(A) and 9(B) is adopted, the sensor unit 20 is placed inside the lumen S formed by one outer tube protruding toward the tip of the other outer tube, and the lumen S is expanded to the outer diameter of the sensor unit 20 and the support 40, so that the first outer tube 50 or the second outer tube 70 covers the outside of the support 40, making it possible to fuse them together using thermal shrinkage or the like. By connecting the sensor unit 20 and each outer tube 50, 70 using the wall thickness of the first outer tube 50 or the wall thickness of the second outer tube 70 in this way, it becomes possible to easily control the outer diameter at the connection position P1 compared to when adhesives or the like are used.

[0127] <Another Modification Example 2> In the image acquisition catheter, for example as shown in Figure 10, the tightly wound portions 61 and loosely wound portions 63 are arranged alternately in the axial direction, and the tightly wound portions 61 include a tip-side region 61C formed at equal intervals in the axial direction and a proximal-side region 61D in which the intervals between the tightly wound portions 61 are not arranged at equal intervals, and the proximal-side region 61D can be configured such that the intervals between the tightly wound portions 61 become smaller as it approaches the bending center.

[0128] When a resin material with a certain degree of rigidity is used for the impermeable member 60 (coil-shaped member), widening the spacing between the loosely wound portions 63 increases the amount of resin per unit length, thereby increasing the axial rigidity of that portion. On the other hand, in the tightly wound portions 61, the impermeable member 60 is tightly wound, increasing its flexibility and improving its ability to follow bending.

[0129] According to this modified example, by adjusting the arrangement of the loosely wound sections 63 and tightly wound sections 61 in a predetermined range (for example, 20 to 40 cm before and after) the center of curvature in the vascular course (for example, near the approximate axial center of each outer tube 50, 70 indicated by the symbol O in the figure), it becomes possible to design the stiffness distribution of the imaging catheter so that a flexible region is formed in the curvature and high pushability is obtained in other straight sections and sections leading to lesions. For example, when considering a crossover approach during treatment of lower limb blood vessels, if the total length of the imaging catheter is set to approximately 120 cm, the spacing of the loosely wound sections 63 can be adjusted in the range of 20 to 40 cm before and after the center of curvature in the section passing through the curvature near the hip joint to form a region with high flexibility to follow curvature. Furthermore, in the straight sections of vascular course before and after that, the stiffness can be increased by widening the spacing of the loosely wound sections 63, improving the ability to push towards the tip. Furthermore, multiple radiopaque markers (RO markers) can be placed in the tip region 61C at intervals of, for example, 10 mm to facilitate the measurement of lesion length and position. This makes it possible to accurately guide the tip position of the image acquisition catheter while visually understanding the length and position of the lesion (stenosis) under X-ray fluoroscopy.

[0130] Although the image acquisition catheter according to the present invention has been described above through embodiments and modifications, the present invention is not limited to the configuration described in the embodiments, and can be modified as appropriate based on the claims.

[0131] This application is based on Japanese Patent Application No. 2025-049294, filed on 25 March 2025, the disclosures of which are incorporated herein by reference in their entirety.

[0132] 1 Medical System 10 Inner tube 11 Tip of inner tube 15 First lumen 20 Sensor section 30 Film sensor 33 Base end of film sensor 37a Transducer 40 Support 41 Tip of support 43 Base end of support 46 Filling material 50 First outer tube 51 Tip of first outer tube 53 Base end of first outer tube 55 Second lumen 60 Impermeable member 60A First section 60B Second section 61 Tightly wound section 61A Tightly wound section 61B Tightly wound section 61C Tip side region 61D Base end region 63 Loosely wound section 70 Second outer tube 71 Tip of second outer tube 73 Base end of second outer tube 75 Housing section 81 Tip side adhesive section 83 Base end adhesive section 85 Connection section 90 Tip member 95 Proximal hub section 98 Wiring section 98a Tip of wiring section 100 Image acquisition catheter 300 External device P1 Connection position c1 Central axis L1 First axial length L2 Second axial length L3 Third axial length Ls1 Spacing of tightly wound sections Ls2 Spacing of loosely wound sections

Claims

1. An image acquisition catheter 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 ultrasonic waves are arranged in a ring shape in the circumferential direction; a first outer tube disposed to cover at least a portion of the inner tube so as to form a second lumen between it and the inner tube; an opaque member having X-ray opacity, wound in a coil shape around the outer surface of the first outer tube; and a second outer tube disposed to cover the opaque member between it and the first 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 the opaque member includes a tightly wound portion and a loosely wound portion disposed at different axial positions of the first outer tube.

2. The tip and proximal end of the second outer tube are bonded or welded to the first outer tube, as described in claim 1.

3. The image acquisition catheter according to claim 2, wherein the tip of the first outer tube is connected to the support at a position closer to the tip of the second outer tube, and the tip of the second outer tube is located closer to the proximal end than the connection point where the first outer tube and the support are connected.

4. The tip of the second outer tube is bonded to the first outer tube by a tip-side adhesive portion, and the tip-side adhesive portion has a tapered shape in which the outer diameter decreases toward the tip, as described in claim 3.

5. The tip of the second outer tube is positioned further forward than the tip of the first outer tube, and the loosely wound portion is positioned radially outward of the connection portion where the inner tube and the support are connected in the impermeable member, as described in claim 1.

6. The image acquisition catheter according to claim 1, wherein the tip of either the first outer tube or the second outer tube is positioned radially outward on the proximal end side of the film sensor, and the tip of the other is provided on the proximal end side of the film sensor.

7. The image acquisition catheter according to claim 1, wherein the second outer tube extends to the proximal end of the first outer tube, and the impermeable member includes a first section in which the tightly wound portion is formed over a first axial length, and a second section in which the tightly wound portion is formed over a second axial length longer than the first axial length, and the second section is formed over a predetermined range from the proximal end of the first outer tube toward the tip.

8. The image acquisition catheter according to claim 1, wherein the tightly wound portions and the loosely wound portions are arranged alternately in the axial direction, and the tightly wound portions are formed at equal intervals in the axial direction.

9. The image acquisition catheter according to claim 1, wherein the tightly wound portions and the loosely wound portions are arranged alternately in the axial direction, and the tightly wound portions comprise a tip-side region formed at equal intervals in the axial direction and a proximal-side region where the intervals between the tightly wound portions are not arranged at equal intervals, and the intervals between the tightly wound portions in the proximal-side region become smaller as it approaches the bending center.

Images