JP7618513B2 - Diagnostic Imaging Catheters - Google Patents

Description

This disclosure relates to a catheter for diagnostic imaging.

Diagnostic imaging catheters generally have a pullback mechanism at their proximal end that changes the relative position between the sheath and the drive shaft in order to continuously observe cross sections inside the body cavity. The pullback mechanism has an outer tube and an inner tube that is located radially inward from the outer tube and radially outward from the drive shaft and that can move axially relative to the outer tube and integrally with the drive shaft.

If the drive shaft buckles inside the outer tube during the pushing operation in which the pullback mechanism pushes the inner tube into the outer tube, there is a risk that the drive shaft will twist and break when it is rotated. For this reason, for example, in the pullback mechanism described in Patent Document 1, a support tube that can move axially together with the outer tube is provided radially outward from the drive shaft and radially inward from the inner tube to prevent the drive shaft from buckling during the pushing operation.

Patent No. 4672188

However, with a support tube such as that described in Patent Document 1, it is difficult to prevent the drive shaft from buckling within the inner tube during a pushing operation.

The present disclosure therefore aims to provide a catheter for diagnostic imaging in which the drive shaft is less likely to buckle not only within the outer tube but also within the inner tube during the pushing operation.

A diagnostic imaging catheter according to one aspect of the present disclosure includes an outer tube, a support tube disposed radially inward of the outer tube, a drive shaft disposed radially inward of the support tube, and an inner tube disposed radially inward of the outer tube and radially outward of the support tube and capable of moving axially relative to the outer tube and the support tube and integrally with the drive shaft, the inner tube having a multiple flow path forming portion that forms a central flow path and one or more flow paths radially outward of the central flow path.

As one embodiment of the present disclosure, the imaging diagnostic catheter is an imaging diagnostic catheter in which the multiple flow path forming portion has a portion that does not overlap with the support tube when viewed radially in a rearwardly retracted state in which the inner tube is pulled out most from within the outer tube.

As one embodiment of the present disclosure, the imaging diagnostic catheter is a catheter for imaging diagnostics in which the multiple flow path forming portion has a portion that overlaps with the support tube when viewed radially in a rearwardly retracted state in which the inner tube is pulled out most from within the outer tube.

As one embodiment of the present disclosure, the imaging diagnostic catheter is an imaging diagnostic catheter in which the one or more flow paths are multiple flow paths arranged in the circumferential direction.

As one embodiment of the present disclosure, the imaging diagnostic catheter is an imaging diagnostic catheter in which the multiple flow path forming portion has a porous structure.

As one embodiment of the present disclosure, the imaging diagnostic catheter is a catheter for imaging diagnostics in which the multiple flow path forming portion has an inner wall that forms the central flow path and one or more connection portions that connect the inner wall to the tube main body portion.

The present disclosure provides a catheter for diagnostic imaging in which the drive shaft is less likely to buckle not only within the outer tube but also within the inner tube during the pushing operation.

FIG. 2 is a plan view showing a state in which an external device is connected to the diagnostic imaging catheter as the first embodiment. FIG. 2 is a side view showing the diagnostic imaging catheter shown in FIG. 1 in a most advanced state before a pull-back operation. FIG. 2 is a side view showing the diagnostic imaging catheter shown in FIG. 1 in a most retreated state after a pull-back operation. FIG. 2 is a cross-sectional view showing the distal end of the diagnostic imaging catheter shown in FIG. 1 . FIG. 2 is a cross-sectional view showing a proximal end of the diagnostic imaging catheter shown in FIG. 1. 2 is a cross-sectional view showing a pull-back mechanism of the diagnostic imaging catheter shown in FIG. 1 in a fully retracted state. FIG. 2 is a cross-sectional view showing the pull-back mechanism of the diagnostic imaging catheter shown in FIG. 1 in a most forward state. FIG. This is a cross-sectional view of AA in FIG. 5A. 6B is a cross-sectional view showing a modified example of the multiple flow path forming portion shown in FIG. 6A. 6B is a cross-sectional view showing another modified example of the multiple flow path forming portion shown in FIG. 6A. 6B is a cross-sectional view showing another modified example of the multiple flow path forming portion shown in FIG. 6A. 6B is a cross-sectional view showing another modified example of the multiple flow path forming portion shown in FIG. 6A.

Embodiments of the present disclosure are described in detail below with reference to the drawings.

The diagnostic imaging catheter 1 according to this embodiment shown in FIG. 1 is a dual type that uses both intravascular ultrasound (IVUS) and optical coherence tomography (OCT). The dual type diagnostic imaging catheter 1 has three modes: a mode for acquiring tomographic images using IVUS only, a mode for acquiring tomographic images using OCT only, and a mode for acquiring tomographic images using IVUS and OCT, and these modes can be switched for use. As shown in FIG. 1, the diagnostic imaging catheter 1 is connected to and driven by an external device 2. The diagnostic imaging catheter 1 and the external device 2 constitute a diagnostic imaging device 3.

The diagnostic imaging catheter 1 has a sheath 4 inserted into a body cavity such as a vessel (blood vessel such as a coronary artery) of a living body, an outer tube 5 connected to the base end of the sheath 4, an inner tube 6 inserted into the outer tube 5 so as to be movable forward and backward, a unit connector 7 connected to the base end of the outer tube 5 and holding the inner tube 6 so as to be movable forward and backward, and a hub 8 connected to the base end of the inner tube 6. The diagnostic imaging catheter 1 also has an imaging core 12 including a drive shaft 9, a housing 10 fixed to the tip of the drive shaft 9, and a signal transmitting/receiving unit 11 housed in the housing 10 and transmitting and receiving signals that are ultrasound and/or light. The imaging core 12 is inserted into the sheath 4, the outer tube 5, and the inner tube 6, and can be moved forward and backward in the axial direction together with the inner tube 6 relative to the sheath 4 and the outer tube 5.

In this specification, the term "tip" refers to the end of the diagnostic imaging catheter 1 that is inserted into the body cavity, the term "base end" refers to the end of the diagnostic imaging catheter 1 that is held outside the body cavity, the term "axial direction" refers to the direction along the central axis O of the drive shaft 9 (i.e., the extension direction of the drive shaft 9), the term "radial direction" refers to the direction along a straight line perpendicular to the central axis O, and the term "circumferential direction" refers to the direction going around the central axis O.

2A, the drive shaft 9 passes through the sheath 4, the outer tube 5, and the inner tube 6 and extends to the inside of the hub 8. The hub 8, the inner tube 6, the drive shaft 9, the housing 10, and the signal transmission/reception unit 11 are connected to each other so that they can move forward and backward in the axial direction together with respect to the sheath 4 and the outer tube 5. For this reason, for example, when the hub 8 is pushed toward the tip side, that is, when a pushing operation is performed, the inner tube 6 connected to the hub 8 is pushed into the outer tube 5 and the unit connector 7, and the drive shaft 9, the housing 10, and the signal transmission/reception unit 11, that is, the imaging core 12, advance inside the sheath 4, that is, move toward the tip side. For example, when the hub 8 is pulled toward the base end side, that is, when a pull-back operation is performed, the inner tube 6 is pulled out from the outer tube 5 and the unit connector 7 as shown by the arrow A1 in FIG. 1 and FIG. 2B, and the imaging core 12 moves inside the sheath 4 toward the base end as shown by the arrow A2.

As shown in FIG. 2A, when the inner tube 6 is pushed all the way toward the tip and reaches its most advanced state, the tip of the inner tube 6 reaches close to the relay connector 13. At this time, the signal transmitting/receiving unit 11 is located at the tip of the sheath 4 (close to the tip surface of the lumen of the sheath 4). The relay connector 13 connects the sheath 4 and the outer tube 5.

As shown in FIG. 2B, the tip of the inner tube 6 is provided with a locking portion 14 to prevent it from coming off. The locking portion 14 prevents the inner tube 6 from coming off the outer tube 5. The locking portion 14 is configured to hook at a predetermined position on the inner wall of the unit connector 7 when the hub 8 is pulled all the way back toward the base end, that is, when the inner tube 6 is pulled all the way out from the outer tube 5 and the unit connector 7.

As shown in FIG. 3, the drive shaft 9 is a long, hollow member, and inside it are arranged an electric signal line (electrical cable) 15 and an optical signal line (optical fiber) 16 that are connected to the signal transmitting/receiving unit 11.

The drive shaft 9 is formed of a coil shaft. Although not shown in the figure, the coil shaft can be formed, for example, of multiple layers of coils with different winding directions. Each coil is made of a metal such as stainless steel or a Ni-Ti (nickel-titanium) alloy.

The signal transmitting/receiving unit 11 has an ultrasonic transmitting/receiving unit 11a that transmits and receives ultrasonic waves, and an optical transmitting/receiving unit 11b that transmits and receives light. The ultrasonic transmitting/receiving unit 11a transmits ultrasonic waves based on a pulse signal into the body cavity, and has a transducer that receives ultrasonic waves reflected from the biological tissue in the body cavity. The transducer is electrically connected to an electrical connector 15a (see FIG. 4) via an electrical signal line 15. The transducer can be made of a piezoelectric material such as ceramics or quartz.

The optical transmitter/receiver 11b has an optical element that transmits light into the body cavity and receives light reflected from biological tissue in the body cavity. The optical element is optically connected to the optical connector 16a (see FIG. 4) via the optical signal line 16. The optical element can be formed by a lens such as a ball lens.

The signal transmitting/receiving unit 11 is accommodated inside the housing 10. The base end of the housing 10 is fixed to the tip of the drive shaft 9. The housing 10 is formed of a cylindrical metal tube, and an opening 10a is provided on the periphery so as not to impede the progress of the signal transmitted and received by the signal transmitting/receiving unit 11. The housing 10 can be formed, for example, by laser processing or the like. The housing 10 may also be formed by cutting out a metal block, MIM (metal powder injection molding), or the like.

A tip member 17 is provided at the tip of the housing 10. The tip member 17 has a substantially hemispherical outer shape, which reduces friction and snagging with the inner surface of the sheath 4. Note that the tip member 17 may not be provided.

The sheath 4 has an inner cavity 4a into which the drive shaft 9 is inserted so as to be movable forward and backward. A tubular guidewire insertion member 18 through which a guidewire can be passed is attached to the tip of the sheath 4, offset from the axis of the inner cavity of the sheath 4. The sheath 4 and the guidewire insertion member 18 are joined by welding or the like. The guidewire insertion member 18 is provided with a marker 19 that is X-ray opaque. The marker 19 is made of a metal pipe that is highly X-ray opaque, such as Pt or Au.

A communication hole 20 that connects the inside and outside of the lumen 4a is formed at the tip of the sheath 4. A reinforcing member 21 that is joined to the guidewire insertion member 18 is provided at the tip of the lumen 4a of the sheath 4. A through hole is formed in the reinforcing member 21 that connects the lumen 4a, which is located on the proximal side of the reinforcing member 21, with the communication hole 20. Note that the reinforcing member 21 does not necessarily have to be provided at the tip of the sheath 4.

The communication hole 20 is a priming fluid discharge hole for discharging the priming fluid. When using the diagnostic imaging catheter 1, when performing a priming process in which the priming fluid is filled into the sheath 4, the priming fluid can be released to the outside through the communication hole 20, and gas such as air can be discharged from the inside of the sheath 4 together with the priming fluid.

The tip end portion of the sheath 4, which is the range in which the signal transmitting/receiving unit 11 moves in the axial direction of the sheath 4, forms a window portion with higher signal permeability than other portions. The sheath 4, the guidewire insertion member 18, and the reinforcing member 21 are made of a flexible material, and the material is not particularly limited, and examples of the material include 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, and combinations of one or more of these (polymer alloys, polymer blends, laminates, etc.) can also be used.

As shown in FIG. 4, the hub 8 has a hub body 8a that is tubular and coaxial with the inner tube 6 and is detachably attached to the external device 2, a port 8b that protrudes radially outward from the hub body 8a and communicates with the inside of the hub body 8a, a connection pipe 8c that is attached integrally to the outer circumferential surface of the drive shaft 9, a bearing 8d that rotatably supports the connection pipe 8c, a seal member (first seal member 8e) that prevents the priming liquid from leaking from between the connection pipe 8c and the bearing 8d toward the base end, and a connector portion 8f that includes an electric connector 15a and an optical connector 16a and is detachably attached integrally to the first drive portion 2a of the external device 2. The connector portion 8f can rotate integrally with the connection pipe 8c and the drive shaft 9.

The base end of the inner tube 6 is integrally connected to the tip end of the hub body 8a. The drive shaft 9 is pulled out from the inner tube 6 inside the hub body 8a.

As shown in FIG. 1, an injection device 22 that injects a priming solution is connected to port 8b when performing the priming process. The injection device 22 has a connector 22a that is connected to port 8b, and a syringe (not shown) that is connected to the connector 22a via a tube 22b. Priming is usually performed in the most retracted state (see FIG. 1 and FIG. 5A).

The external device 2 has a first drive unit 2a for driving the drive shaft 9 to rotate, and a second drive unit 2b for moving the drive shaft 9 in the axial direction (i.e., for pushing/pulling back operations). The first drive unit 2a can be configured, for example, by an electric motor. The second drive unit 2b can be configured, for example, by an electric motor and a linear motion conversion mechanism. The linear motion conversion mechanism can convert rotational motion into linear motion, and can be configured, for example, by a ball screw or a rack and pinion mechanism.

The operation of the first drive unit 2a and the second drive unit 2b is controlled by a control device 2c electrically connected thereto. The control device 2c includes a CPU (Central Processing Unit) and a memory. The control device 2c is electrically connected to a display 2d.

The signal received by the ultrasonic transmission/reception unit 11a is sent to the control device 2c via the electrical connector 15a, where it is subjected to a predetermined processing and displayed as an image on the display 2d. The signal received by the optical transmission/reception unit 11b is sent to the control device 2c via the optical connector 16a, where it is subjected to a predetermined processing and displayed as an image on the display 2d.

When making a diagnosis, the sheath 4 is inserted into the body cavity, and the imaging core 12 is rotated and driven at a constant rotation speed of about 1,000 to 10,000 rpm by the first drive unit 2a of the external device 2, while the imaging core 12 is pulled back by the second drive unit 2b of the external device 2 to move it backward at a constant speed within the inner cavity 4a of the sheath 4. At this time, the control unit 2c of the external device 2 transmits and receives signals at the signal transmitting/receiving unit 11. Based on the signals received by scanning caused by this rotation and backward movement, the condition of the tissues around the body cavity is displayed as an image on the display 2d.

In this way, the diagnostic imaging catheter 1 has a pull-back mechanism 23 at the proximal portion that changes the relative position between the sheath 4 and the drive shaft 9 in order to continuously observe the cross section of the body cavity. As shown in Figs. 5A and 5B, the pull-back mechanism 23 has an outer tube 5, an inner tube 6 that is provided radially inward from the outer tube 5 and radially outward from the drive shaft 9 and is movable in the axial direction relative to the outer tube 5 and integrally with the drive shaft 9, a support tube 24 that is provided radially inward from the inner tube 6 and radially outward from the drive shaft 9, a spacer 25 that integrally connects the outer tube 5 and the support tube 24, a relay connector 13, and a unit connector 7. As described above, the relay connector 13 is integrally connected to the sheath 4, and the inner tube 6 is integrally connected to the hub 8. The unit connector 7 is provided with a seal member (second seal member 7a) that prevents the priming liquid from leaking from between the unit connector 7 and the inner tube 6 toward the base end side.

A locking portion 14 is provided at the tip of the inner tube 6. The locking portion 14 is configured as an enlarged diameter portion where the outer circumferential surface of the inner tube 6 is enlarged, and the rear end surface of the locking portion 14 protrudes radially outward from the outer circumferential surface of the inner tube 6 and forms an annular shape centered on the central axis O. The unit connector 7 has a stopper surface 7b that abuts against the rear end surface of the locking portion 14 to restrict further retraction of the inner tube 6. The inner tube 6 has a diameter dimension sufficient to provide the locking portion 14 with sufficient strength as a stopper.

In the pullback mechanism 23, the outer tube 5, the support tube 24, the inner tube 6 and the drive shaft 9 are arranged coaxially and have a common central axis O.

The relay connector 13 is cylindrical and has a cylindrical base end inner circumferential surface 13a and a cylindrical tip end inner circumferential surface 13c that is connected to the tip of the base end inner circumferential surface 13a via an annular step 13b. The outer circumferential surface of the base end of the sheath 4 is joined to the tip end inner circumferential surface 13c by welding or the like. The outer circumferential surface of the tip of the outer tube 5 is joined to the base end inner circumferential surface 13a by welding or the like.

The spacer 25 is cylindrical, with its outer peripheral surface in contact with the inner peripheral surface of the tip of the outer tube 5, and its inner peripheral surface in contact with the outer peripheral surface of the tip of the support tube 24. The outer peripheral surface of the spacer 25 is joined to the inner peripheral surface of the tip of the outer tube 5 by welding or the like, and the inner peripheral surface of the spacer 25 is joined to the outer peripheral surface of the tip of the support tube 24 by welding or the like. The spacer 25 is made of, for example, synthetic resin or metal.

The support tube 24 can be formed, for example, of a single layer or multiple layers of coil or tube. The support tube 24 is made, for example, of synthetic resin or metal. By using a coiled support tube 24, the priming liquid can pass through the support tube 24 in the radial direction, thereby promoting priming within the outer tube 5. Instead of a coiled shape, the support tube 24 may be formed into a tube with a mesh-like or other cutouts in the whole or part. The support tube 24 may also be formed into a tube without cutouts. In this case, in order to promote priming within the outer tube 5, it is preferable to provide the spacer 25 with a flow path through which the priming liquid can pass.

In this embodiment, the inner pipe 6 has a long tubular (long cylindrical in this embodiment) pipe main body 6a and a multiple flow passage forming portion 6b provided radially inward from the pipe main body. The multiple flow passage forming portion is a portion that forms a central flow passage 6c and one or more flow passages (hereinafter also referred to as outer flow passages 6d) radially outward from the central flow passage 6c. More specifically, as shown in FIG. 6A, the multiple flow passage forming portion 6b has a cylindrical inner wall 6e centered on the central axis O and one or more connecting portions 6f that connect the inner wall 6e to the pipe main body 6a. In this embodiment, each connecting portion 6f is ribbed and extends over the entire axial length of the inner wall 6e, and as a result, two outer flow passages 6d aligned in the circumferential direction are formed. Each connecting portion 6f extends, for example, along the axial direction.

The circumferential arrangement of the rib-shaped connecting parts 6f is not particularly limited, and may be arranged, for example, 90° offset in the circumferential direction as shown in FIG. 6B. The number of outer flow paths 6d can be increased by increasing the number of rib-shaped connecting parts 6f. For example, four outer flow paths 6d can be provided as shown in FIG. 6C, or eight outer flow paths 6d can be provided as shown in FIG. 6D. By configuring the multiple flow path forming part 6b to form multiple outer flow paths 6d arranged in the circumferential direction, the rigidity of the inner pipe 6 can be efficiently increased, thereby making it possible to thin the inner pipe 6 and increase the flow path cross-sectional area. The multiple outer flow paths 6d are arranged point symmetrically with respect to the central axis O, but this is not limited thereto.

The pipe body 6a, the inner wall 6e, and the connection portion 6f can be integrally formed, for example, by extrusion molding. However, they may also be formed separately and then integrated with an adhesive or the like.

A single outer flow path 6d may be provided by providing one rib-shaped connection portion 6f, or by providing the connection portion 6f in a dot shape rather than a rib shape.

The multiple flow passage forming portion 6b may have a porous structure. For example, a part or all of the multiple flow passage forming portion 6b having an inner wall 6e and one or more connection portions 6f may be formed of a porous body. Alternatively, as shown in FIG. 7, the multiple flow passage forming portion 6b may be formed of a long cylindrical porous body in contact with the inner peripheral surface of the pipe main body portion 6a. In this case, the central flow passage 6c is formed by the inner peripheral surface of the porous body, and the outer flow passages 6d are formed by the numerous cavities inside the porous body.

As shown in FIG. 5A, the multiple flow passage forming portion 6b is provided over the entire axial length of the pipe main body portion 6a. Therefore, the multiple flow passage forming portion 6b has a portion (hereinafter also referred to as a non-overlapping portion 6g) that does not overlap with the support tube 24 when viewed in the radial direction in the most withdrawn state (state shown in FIG. 5A) in which the inner pipe 6 is pulled out most from inside the outer pipe 5. As a result, when the inner pipe 6 and the drive shaft 9 are advanced relative to the outer pipe 5 and the support tube 24 by a pushing operation from the most withdrawn state, the drive shaft 9 is supported from the radial outside by the support tube 24 to prevent the drive shaft 9 from buckling in the outer pipe 5 (for example, as shown by a two-dot chain line in FIG. 5A), and the drive shaft 9 is supported from the radial outside by the inner peripheral surface of the inner wall 6e of the non-overlapping portion 6g of the multiple flow passage forming portion 6b to prevent the drive shaft 9 from buckling in the inner pipe 6 (for example, as shown by a two-dot chain line in FIG. 5A). Therefore, the drive shaft 9 is rotated in a buckled state within the pullback mechanism 23, which prevents the drive shaft 9 from twisting and breaking.

As shown in FIG. 5A, the multiple flow passage forming portion 6b has a portion (hereinafter, also referred to as overlapping portion 6h) that overlaps with the support tube 24 when viewed in the radial direction in the most retreated state. Therefore, when the inner tube 6 and the drive shaft 9 are advanced from the most retreated state relative to the outer tube 5 and the support tube 24 by a pushing operation, the support tube 24 is supported from the radial outside by the inner peripheral surface of the inner wall 6e of the overlapping portion 6h of the multiple flow passage forming portion 6b, so that the support tube 24 can be prevented from buckling in the inner tube 6. Therefore, the drive shaft 9 is rotated in a buckled state in the pullback mechanism 23, and the occurrence of breakage in which the drive shaft 9 is twisted off can be further prevented. From another perspective, when the inner tube 6 and the drive shaft 9 are advanced from the most retreated state relative to the outer tube 5 and the support tube 24 by a pushing operation, it is possible to prevent the base end of the support tube 24 and the tip end of the inner tube 6 from coming into contact with each other and interfering with the pushing operation.

The multiple flow passage forming portion 6b is not limited to a configuration that extends over the entire axial length of the pipe main body portion 6a, and may be, for example, a configuration that has a non-overlapping portion 6g without an overlapping portion 6h, or a configuration that has an overlapping portion 6h without a non-overlapping portion 6g. In either configuration, the multiple flow passage forming portion 6b can suppress the occurrence of breakage in which the drive shaft 9 is twisted off.

In addition, since the inner tube 6 has an outer flow path 6d, the priming liquid passes through the inner tube 6 more easily than in a configuration in which the inner diameter of the inner tube 6 is simply reduced, so the priming resistance is reduced and good priming performance can be ensured.

This disclosure is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present disclosure.

Therefore, the diagnostic imaging catheter 1 according to the embodiment described above can be modified in various ways, for example as described below.

The diagnostic imaging catheter 1 according to the embodiment described above has an outer tube 5, a support tube 24 provided radially inward from the outer tube 5, a drive shaft 9 provided radially inward from the support tube 24, and an inner tube 6 provided radially inward from the outer tube 5 and radially outward from the support tube 24 and capable of moving in the axial direction relative to the outer tube 5 and the support tube 24 and integrally with the drive shaft 9, and the inner tube 6 can be modified in various ways as long as it is a diagnostic imaging catheter 1 having a multiple flow path forming portion 6b that forms a central flow path 6c and one or more flow paths (outer flow paths 6d) radially outward from the central flow path 6c.

For example, the tip of the support tube 24 may be directly and integrally connected to the relay connector 13 or the outer tube 5 using adhesive or the like without providing the spacer 25.

The pullback mechanism 23 is not limited to a configuration in which the outer tube 5 is integrally connected to the relay connector 13 and the inner tube 6 is integrally connected to the hub 8, but may be a configuration in which the outer tube 5 is integrally connected to the hub 8 and the inner tube 6 is integrally connected to the relay connector 13.

The diagnostic imaging catheter 1 is not limited to a dual type that uses both IVUS and OCT, but may be a type that uses only IVUS or only OCT.

It is preferable that the imaging diagnostic catheter 1 according to the above-mentioned embodiment is an imaging diagnostic catheter 1 in which the multiple flow path forming portion 6b has a portion (non-overlapping portion 6g) that does not overlap with the support tube 24 when viewed in the radial direction in the most retracted state in which the inner tube 6 is pulled out most from inside the outer tube 5.

The diagnostic imaging catheter 1 according to the above-described embodiment is preferably a diagnostic imaging catheter 1 in which the multiple flow path forming portion 6b has a portion (overlapping portion 6h) that overlaps with the support tube 24 when viewed radially in the most retracted state in which the inner tube 6 is pulled out most from within the outer tube 5.

The diagnostic imaging catheter 1 according to the embodiment described above is preferably a diagnostic imaging catheter 1 in which one or more flow paths (outer flow path 6d) are multiple flow paths arranged in the circumferential direction.

The diagnostic imaging catheter 1 according to the above-described embodiment is preferably a diagnostic imaging catheter 1 in which the multiple flow path forming portion 6b has a porous structure.

REFERENCE SIGNS LIST 1 Diagnostic imaging catheter 2 External device 2a First drive section 2b Second drive section 2c Control device 2d Display 3 Diagnostic imaging device 4 Sheath 4a Sheath lumen 5 Outer tube 6 Inner tube 6a Tube body section 6b Multiple flow path forming section 6c Central flow path 6d Outer flow path 6e Inner wall 6f Connection section 6g Non-overlapping section 6h Overlapping section 7 Unit connector 7a Second seal member 7b Stopper surface 8 Hub 8a Hub body 8b Port 8c Connection pipe 8d Bearing 8e First seal member 8f Connector section 9 Drive shaft 10 Housing 10a Opening 11 Signal transmitting/receiving section 11a Ultrasound transmitting/receiving section 11b Light transmitting/receiving section 12 Imaging core 13 Relay connector 13a Base end side inner peripheral surface 13b Step section 13c Tip end side inner peripheral surface 14 Locking portion 15 Electric signal line 15a Electric connector 16 Optical signal line 16a Optical connector 17 Tip member 18 Guide wire insertion member 19 Marker 20 Communication hole 21 Reinforcing member 22 Injection device 22a Connector 22b Tube 23 Pullback mechanism 24 Support tube 25 Spacer O Central axis

Claims (6)

an outer tube, a support tube provided radially inward from the outer tube, a drive shaft provided radially inward from the support tube, and an inner tube provided radially inward from the outer tube and radially outward from the support tube, and axially movable relative to the outer tube and the support tube and integrally with the drive shaft,
The catheter for diagnostic imaging, wherein the inner tube has a multiple flow passage forming portion that forms a central flow passage and one or more flow passages radially outward from the central flow passage. The diagnostic imaging catheter according to claim 1, wherein the multiple flow path forming section has a portion that does not overlap with the support tube when viewed in the radial direction in a rearwardly retracted state in which the inner tube is pulled out most from within the outer tube. The diagnostic imaging catheter according to claim 1 or 2, wherein the multiple flow path forming section has a portion that overlaps with the support tube when viewed in the radial direction in a rearwardly retracted state in which the inner tube is pulled out most from within the outer tube. The diagnostic imaging catheter according to any one of claims 1 to 3, wherein the one or more flow paths are multiple flow paths arranged in a circumferential direction. The diagnostic imaging catheter according to any one of claims 1 to 4, wherein the multiple flow path forming portion has a porous structure. The inner tube has a long cylindrical tube main body portion,
The diagnostic imaging catheter according to any one of claims 1 to 5, wherein the multiple flow path forming portion has an inner wall that forms the central flow path, and one or more connection portions that connect the inner wall to the tube main body portion.

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