WO2023282237A1

WO2023282237A1 - Catheter for diagnostic imaging

Info

Publication number: WO2023282237A1
Application number: PCT/JP2022/026635
Authority: WO
Inventors: 智弘福田; 総一郎杉原; 智司丸山
Original assignee: テルモ株式会社
Priority date: 2021-07-05
Filing date: 2022-07-04
Publication date: 2023-01-12
Also published as: JPWO2023282237A1

Abstract

A catheter for diagnostic imaging according to the present disclosure comprises: a sheath; a drive shaft inserted into the sheath; an image sensor fixed to the drive shaft; an outer tube fixed to a proximal end part of the sheath; an inner tube accommodating a proximal end part of the drive shaft and movable within the outer tube together with the drive shaft; and a protective tube fixed to a proximal side of the sheath and that is moved within the inner tube as the inner tube moves within the outer tube, the protective tube allowing the drive shaft to be passed therein. The drive shaft includes a highly rigid section at least in a portion of a shaft base end part that is accommodated within the protective tube in a pushed-in state in which the inner tube is maximally pushed into the outer tube and that is located outside the protective tube in a pulled-out state in which the inner tube is maximally pulled out from the outer tube, the highly rigid section having a higher bending rigidity than a portion that is located within the sheath in the pulled-out state.

Description

diagnostic imaging catheter

The present disclosure relates to diagnostic imaging catheters.

Conventionally, an ultrasound catheter that obtains images by intravascular ultrasound (Intravascular Ultrasound, abbreviated as "IVUS") has been known as an example of diagnostic imaging catheters that obtain tomographic images of blood vessels and the like. Patent Literature 1 discloses this type of ultrasound catheter.

The ultrasound catheter described in Patent Document 1 includes a catheter sheath to be inserted into a blood vessel, and a drive shaft movable together with an ultrasound transducer within the catheter sheath. A connection port and a sheath connector are connected to the proximal side of the catheter sheath described in Patent Document 1. A drive shaft connector is connected to the proximal side of the drive shaft described in Patent Document 1. A distal side of the drive shaft connector described in Patent Document 1 is provided with a guide tube that covers a predetermined portion of the proximal side of the drive shaft.

JP-A-2000-189517

In the ultrasound catheter described in Patent Document 1, the guide tube and the drive shaft connector (hereinafter, the guide tube and the drive shaft connector are simply referred to as "inner tube") as the inner tube are connected as the outer tube. It is configured to be movable inside the port and sheath connector (hereinafter, the connection port and sheath connector are simply referred to as "outer tube"). As a result, the ultrasonic transducer as the ultrasonic sensor and the drive shaft can move in the longitudinal direction of the catheter sheath. In addition, in the ultrasound catheter described in Patent Document 1, the drive shaft is configured to be rotatable around the central axis of the drive shaft inside the inner tube and the outer tube.

In an ultrasound catheter as a diagnostic imaging catheter as described in Patent Document 1, there is a risk that the drive shaft will bend or meander inside the inner tube and the outer tube. Bending or breaking of the drive shaft can occur when the drive shaft bends or meanders.

An object of the present disclosure is to provide a diagnostic imaging catheter capable of suppressing bending and meandering of the drive shaft inside the inner tube and the outer tube.

A diagnostic imaging catheter as a first aspect of the present disclosure comprises a sheath inserted into a body cavity, a drive shaft inserted into the sheath, and an image sensor fixed to a distal end of the drive shaft. an outer tube fixed to the proximal end of the sheath; an inner tube that accommodates the proximal end of a drive shaft and is movable within the outer tube together with the drive shaft; and a proximal side of the sheath. a protective tube that is fixed to the inner tube and moves within the inner tube as the inner tube moves within the outer tube, and passes the drive shaft through the protective tube; at least a part of the proximal end of the shaft that is housed in the protective tube in a state of being pushed most into the tube and positioned outside the protective tube in a drawn state of being pulled out of the outer tube most, A high-rigidity portion having greater flexural rigidity than a portion located inside the sheath in the pulled-out state is provided.

As one embodiment of the present disclosure, the drive shaft has, in the shaft base end portion, a region equal to or larger than at least the length of the radius of the inner diameter of the inner tube in the shaft axial direction of the drive shaft. is provided with the high rigidity portion.

As one embodiment of the present disclosure, the drive shaft includes the high-rigidity portion over the entire area of the shaft base end in the shaft axial direction.

As one embodiment of the present disclosure, when the shaft base end is a proximal shaft base end, the drive shaft is housed in the protective tube in the pushed state and the pulled out state. The high-rigidity portion is further provided on at least a portion of the shaft base end.

As one embodiment of the present disclosure, the drive shaft does not include the high-rigidity portion at a portion positioned inside the sheath in the pushed state.

According to the present disclosure, it is possible to provide a diagnostic imaging catheter capable of suppressing bending and meandering of the drive shaft inside the inner tube and the outer tube.

1 is a diagram showing a diagnostic imaging apparatus to which an ultrasound catheter as an embodiment of a diagnostic imaging catheter according to the present disclosure and an external device are connected; FIG. FIG. 2 is a view showing the ultrasound catheter alone shown in FIG. 1; FIG. 3 is a schematic diagram of the operating portion of the ultrasound catheter shown in FIG. 2, showing a pulled-out state in which the inner tube is most pulled out from the outer tube to the proximal side. FIG. 3 is a schematic view of the operating portion of the ultrasound catheter shown in FIG. 2, showing a pushed state in which the inner tube is pushed farthest distally toward the inside of the outer tube. FIG. 3 is a partial cross-sectional view showing details of a portion of the drive shaft and a portion of the electric signal line of the ultrasound catheter shown in FIG. 2, and a diagram showing the configuration of the high-rigidity portion of the drive shaft; FIG. 5 is a view showing a modification of the high-rigidity portion of the drive shaft shown in FIG. 4; FIG. 5 is a view showing a modification of the high-rigidity portion of the drive shaft shown in FIG. 4; FIG. 5 is a view showing a modification of the high-rigidity portion of the drive shaft shown in FIG. 4; FIG. 10 is a schematic diagram of the operation section of the ultrasound catheter in the pulled-out state, showing a modification of the arrangement of the high-rigidity section of the drive shaft. FIG. 8B is a schematic diagram showing a pushed-out state of the operating portion of the ultrasound catheter shown in FIG. 8A;

An embodiment of a diagnostic imaging catheter according to the present disclosure will be described below with reference to the drawings. The same reference numerals are given to the configurations that are common in each figure.

In the present disclosure, the longitudinal direction of the diagnostic imaging catheter is referred to as "longitudinal direction A". In the present disclosure, the side of the catheter for diagnostic imaging that is inserted into the living body in the longitudinal direction A is referred to as the "distal side." The "proximal side" refers to the proximal side of the diagnostic imaging catheter that is manipulated in vitro in the longitudinal direction A. Also, the direction from the proximal side to the distal side of the diagnostic imaging catheter may be simply referred to as "insertion direction A1". The direction from the distal end side to the proximal end side of the diagnostic imaging catheter may be simply referred to as "removal direction A2".

First, a diagnostic imaging apparatus 100 including an ultrasound catheter 110 as an embodiment of a diagnostic imaging catheter according to the present disclosure will be described. FIG. 1 is a diagram showing a diagnostic imaging apparatus 100. As shown in FIG. The diagnostic imaging apparatus 100 includes an ultrasound catheter 110 and an external device 120 . FIG. 1 shows the ultrasound catheter 110 connected to an external device 120 . Hereinafter, in the present specification, the ultrasonic catheter 110 will be exemplified as a diagnostic imaging catheter, but the diagnostic imaging catheter according to the present disclosure is not limited to the ultrasonic catheter 110 shown in this embodiment. The diagnostic imaging catheter may be, for example, a catheter that enables Optical Coherence Tomography (abbreviated as "OCT"), Near Infrared Spectroscopy (abbreviated as "NIRS"), and the like. In such a case, the diagnostic imaging catheter may be configured to include an optical sensor as an image sensor instead of or in addition to the ultrasonic sensor 60 described later.

<Ultrasound catheter 110>
FIG. 2 is a diagram showing the ultrasound catheter 110 shown in FIG. 1 alone. The ultrasound catheter 110 is applied to intravascular ultrasound (Intravascular Ultrasound, abbreviated as "IVUS"). As shown in FIG. 1, the ultrasound catheter 110 is driven by being connected to an external device 120 . More specifically, the ultrasound catheter 110 of this embodiment is connected to the driving unit 120a of the external device 120. As shown in FIG.

As shown in FIGS. 1 and 2, the ultrasound catheter 110 includes an insertion section 110a and an operation section 110b. The insertion portion 110a is a portion of the ultrasound catheter 110 that is used by being inserted into the living body. The operation part 110b is a part of the ultrasound catheter 110 that is operated outside the body while the insertion part 110a is inserted into the body. In the ultrasonic catheter 110 of the present embodiment, the portion on the distal side of a distal connector 42 to be described later is the insertion portion 110a, and the portion on the proximal side of the distal connector 42 is the operating portion 110b.

As shown in FIGS. 1 and 2, the insertion section 110a includes a distal portion of the ultrasonic probe 10 and the sheath 20. As shown in FIGS. Although the details will be described later, the distal side portion of the ultrasonic probe 10 included in the insertion portion 110a includes the ultrasonic sensor 60, the distal side portion of the drive shaft 13, and the electric signal line 14 (Fig. 4) on the distal side.

The operation part 110b can move the drive shaft 13 within the sheath 20 in the longitudinal direction of the sheath 20 (the same direction as the longitudinal direction A). As shown in FIGS. 1 and 2, the operation section 110b includes a proximal portion of the ultrasonic probe 10, an inner tube 30, an outer tube 40, and a protective tube 50. As shown in FIGS. Although the details will be described later, the proximal portion of the ultrasonic probe 10 included in the operation portion 110b includes the proximal portion of the drive shaft 13 and the proximal portion of the electrical signal line 14 (see FIG. 4). It consists of a side part and a

The inner tube 30 holds the proximal end of the ultrasound probe 10 (hereinafter, the "proximal end" is simply referred to as the "proximal end"). Outer tube 40 holds the proximal end of sheath 20 . Although the details will be described later, the ultrasonic probe 10 moves in the longitudinal direction A within the sheath 20 by moving the inner tube 30 in the outer tube 40 in the central axis direction (the same direction as the longitudinal direction A). can be done.

[Ultrasonic probe 10]
3A and 3B are schematic diagrams of the operating portion 110b of the ultrasound catheter 110. FIG. FIG. 3A shows a drawn state in which the inner tube 30 is most drawn proximally from the outer tube 40 . FIG. 3B shows a pushed state in which the inner tube 30 is pushed most distally into the outer tube 40 . Hereinafter, the state shown in FIG. 3A may be simply referred to as "pulled out state". Also, the state shown in FIG. 3B may be simply described as a "pressed state". FIG. 4 is a partial cross-sectional view showing details of a portion of drive shaft 13 and a portion of electrical signal line 14 of ultrasound catheter 110 .

As shown in FIG. 2, the ultrasonic probe 10 includes an ultrasonic sensor 60 as an image sensor, a drive shaft 13, an electric signal line 14 extending through the drive shaft 13 (see FIG. 4), Prepare. The ultrasonic sensor 60 includes an ultrasonic transducer and a housing.

As shown in FIG. 2, the ultrasonic sensor 60 is fixed to the distal end of the drive shaft 13 (hereinafter, the distal end is simply referred to as the "distal end"). . The ultrasonic transducer of ultrasonic sensor 60 includes a piezoelectric element. A piezoelectric element is composed of a flat piezoelectric body and electrodes laminated on the piezoelectric body. Ultrasonic waves can be transmitted and received by the ultrasonic transducer.

The housing of the ultrasonic sensor 60 supports the ultrasonic transducer. The proximal side of the housing is connected to drive shaft 13 . The housing may be integrated with the drive shaft 13 . Therefore, the housing may be directly connected to the drive shaft 13 by adhesion or the like, or may be indirectly connected to the drive shaft 13 via a connector or the like.

As shown in FIG. 2, the drive shaft 13 is inserted into the sheath 20. The drive shaft 13 is configured by a tubular body having flexibility. As shown in FIG. 4, the electric signal line 14 connected to the ultrasonic transducer of the ultrasonic sensor 60 is arranged inside the drive shaft 13 . The drive shaft 13 is composed of, for example, multiple layers of coils with different winding directions around the axis. Although the details will be described later, the drive shaft 13 of the present embodiment is composed of three layers of coils (see FIG. 4, etc.). Materials for the coil include, for example, stainless steel and Ni--Ti (nickel-titanium) alloy. By using such a drive shaft 13, even if the two electric signal lines 14 are composed of a double-helical twisted pair cable, the shielding property is enhanced and the influence of noise generated from the electric signal lines 14 is reduced. be able to.

The drive shaft 13 extends through the interior of the sheath 20, the inner tube 30, the outer tube 40 and the protective tube 50, as shown in FIGS. As mentioned above, the distal end of drive shaft 13 is connected to the housing of ultrasonic sensor 60 . A proximal end of the drive shaft 13 is held by a later-described hub 32 forming a proximal end of the inner tube 30 . That is, the drive shaft 13 extends in the longitudinal direction A from the distal end of the insertion section 110a to the proximal end of the operation section 110b.

As shown in FIG. 4 , the electrical signal line 14 extends inside the drive shaft 13 . The electric signal line 14 electrically connects the ultrasonic transducer of the ultrasonic sensor 60 (see FIG. 2) and the external device 120 (see FIG. 1). In other words, the electric signal line 14 extends in the longitudinal direction A from the distal end of the insertion section 110a to the proximal end of the operation section 110b, like the drive shaft 13 does. A plurality of electric signal lines 14 (two in this embodiment) are provided, and each electric signal line 14 is connected to an electrode of an ultrasonic transducer of the ultrasonic sensor 60 . The plurality of electrical signal lines 14 are composed of, for example, twisted pair cables in which two electrical signal lines 14 are twisted together. Each electrical signal line 14 can be a flexible thin wire member having an outer diameter greater than 0 mm and less than or equal to 0.1 mm. Each electric signal line 14 can be composed of, for example, a conducting wire and a covering material that is formed of an insulating material and covers the circumference of the conducting wire.

[Sheath 20]
The sheath 20 is inserted into a body cavity such as a blood vessel. As shown in FIG. 2, the sheath 20 includes a body portion 20a and a guidewire insertion portion 20b. A first hollow portion is defined inside the body portion 20a. A second hollow portion is defined in the guide wire insertion portion 20b. The ultrasonic probe 10 is accommodated in the first hollow portion of the body portion 20a. The ultrasonic probe 10 can move back and forth in the longitudinal direction A in the first hollow portion. A guide wire can be inserted through the second hollow portion of the guide wire insertion portion 20b. As shown in FIG. 2, in this embodiment, the tubular guidewire insertion portion 20b is adjacent to the distal end portion of the tubular body portion 20a so as to be parallel to each other. The main body portion 20a and the guidewire insertion portion 20b may be formed by joining different tube members by heat sealing or the like.

The sheath 20 is made of a flexible material, and the material is not particularly limited. Examples of constituent materials include various thermoplastic elastomers such as polyethylene, styrene, polyolefin, polyurethane, polyester, polyamide, polyimide, polybutadiene, transpolyisoprene, fluororubber, and chlorinated polyethylene. Alternatively, polymer alloys, polymer blends, laminates, etc. in which two or more types are combined can also be used.

The main body portion 20a may have a reinforcement portion at its proximal end that is reinforced with a highly rigid material. The reinforcing portion may be formed, for example, by arranging a reinforcing material in which a metal wire made of stainless steel or the like is braided in a mesh shape to a tubular member having flexibility such as resin. The tubular member may be formed, for example, from the material of the sheath 20 described above.

[Inner tube 30 and outer tube 40]
Inner tube 30 houses the proximal end of drive shaft 13 and is movable within outer tube 40 with drive shaft 13 . As shown in FIGS. 1, 2, 3A, and 3B, the inner tube 30 includes an inner tube main body 31 and a hub 32. As shown in FIGS. The inner tube main body 31 is inserted in the outer tube 40 so as to be movable forward and backward. The hub 32 is connected to the proximal side of the inner tube main body 31 .

As shown in FIGS. 1, 2, 3A and 3B, the outer tube 40 is fixed to the proximal end of the sheath 20. As shown in FIGS. The outer tube 40 of this embodiment includes an outer tube body 41 , a distal connector 42 and a proximal connector 43 . The outer tube body 41 is located radially outside the inner tube body 31 , and the inner tube body 31 moves back and forth inside the outer tube body 41 . The distal connector 42 connects the proximal end of the main body 20 a of the sheath 20 and the distal end of the outer tube main body 41 . The proximal connector 43 is fixed to the proximal end of the outer tube main body 41 .

The drive shaft 13 and the electric signal line 14 of the ultrasonic probe 10 described above are connected to the main body 20a of the sheath 20, the outer tube 40 connected to the proximal side of the main body 20a, and the outer tube 40. It extends to a hub 32 which constitutes the proximal end of inner tube 30 into which the section is inserted.

The ultrasonic probe 10 and the inner tube 30 described above are connected to each other so that they move back and forth in the longitudinal direction A integrally. Therefore, for example, when the inner tube 30 is pushed in the insertion direction A1, the inner tube 30 is pushed into the outer tube 40 in the insertion direction A1 as shown in FIG. 3B. When the inner tube 30 is pushed into the outer tube 40 in the insertion direction A1, the ultrasonic probe 10 connected to the inner tube 30 moves inside the main body 20a of the sheath 20 in the insertion direction A1. Conversely, when the inner tube 30 is pulled in the removal direction A2, the inner tube 30 is pulled out from the outer tube 40 in the removal direction A2 as shown in FIG. 3A. When the inner tube 30 is pulled out from the outer tube 40 in the withdrawal direction A2, the ultrasonic probe 10 connected to the inner tube 30 moves inside the main body 20a of the sheath 20 in the withdrawal direction A2.

As shown in FIG. 3B, the distal end of the inner tube 30 reaches near the distal connector 42 of the outer tube 40 when the inner tube 30 is pushed in the insertion direction A1 to the maximum. At this time, the ultrasonic sensor 60 of the ultrasonic probe 10 is positioned near the distal end of the body portion 20a of the sheath 20 .

The inner tube 30 and the outer tube 40 are provided with pull-out stoppers that prevent the inner tube 30 from slipping out of the outer tube 40 when the inner tube 30 is pulled out from the outer tube 40 in the pull-out direction A2. ing. The removal-preventing stopper on the pull-out side of the present embodiment is composed of the distal end portion 31a of the inner tube main body 31 of the inner tube 30 and the abutting wall portion 43b of the proximal connector 43 of the outer tube 40. . A distal end portion 31a of an inner tube main body 31 of the inner tube 30 has an annular projection projecting radially outward. The annular convex portion of the distal end portion 31a abuts against the abutment wall portion 43b of the proximal connector 43, thereby restricting movement of the inner tube 30 with respect to the outer tube 40 in the withdrawal direction A2. That is, in the present embodiment, the pulled-out state (see FIG. 3A) in which the inner tube 30 is pulled out from the outer tube 40 to the maximum in the pulling direction A2 means that the annular protrusion 31a of the inner tube main body 31 of the inner tube 30 means a state in which the portion is in contact with the abutment wall portion 43b of the proximal connector 43 of the outer tube 40. As shown in FIG.

Further, the inner tube 30 and the outer tube 40 are provided with a push-side pull-out mechanism that prevents the inner tube 30 from slipping out of the outer tube 40 when the inner tube 30 is pushed into the outer tube 40 in the insertion direction A1. A stop is provided. The push-side retaining stopper of this embodiment is composed of the distal end surface 32 a of the hub 32 of the inner tube 30 and the proximal end surface 43 a of the proximal connector 43 of the outer tube 40 . The distal end surface 32a of the hub 32 of the inner tube 30 contacts the proximal end surface 43a of the proximal connector 43 of the outer tube 40, thereby restricting movement of the inner tube 30 with respect to the outer tube 40 in the insertion direction A1. . That is, in the present embodiment, the most pushed state (see FIG. 3B) in which the inner tube 30 is pushed into the outer tube 40 in the insertion direction A1 means that the distal end surface 32a of the hub 32 of the inner tube 30 is It means a state in which the proximal end face 43a of the proximal connector 43 of the tube 40 is in contact.

However, the pull-out side and push-in side retainer stoppers provided on the inner tube 30 and the outer tube 40 are not limited to the configuration described above. The configuration is not particularly limited as long as it prevents the inner tube 30 from falling out of the outer tube 40 on the pull-out side and the push-in side.

The proximal end of the hub 32 of the inner tube 30 is provided with a connector section that is mechanically and electrically connected to the external device 120 (see FIG. 1). In other words, the ultrasound catheter 110 is mechanically and electrically connected to the external device 120 by the connector provided on the hub 32 of the inner tube 30 . More specifically, the electric signal line 14 of the ultrasonic probe 10 extends from the ultrasonic transducer of the ultrasonic sensor 60 to the connector portion of the hub 32 of the inner tube 30, and connects to the connector portion of the hub 32. is connected to the external device 120, the ultrasonic transducer of the ultrasonic sensor 60 and the external device 120 are electrically connected. A signal received by the ultrasonic transducer is transmitted to the external device 120 via the connector section of the hub 32, subjected to predetermined processing, and displayed as an image.

[protection tube 50]
As shown in FIGS. 3A and 3B, protective tube 50 is fixed to the proximal side of sheath 20 . More specifically, the protective tube 50 is fixed to the proximal end of the sheath 20 together with the outer tube main body 41 of the outer tube 40 via the distal connector 42 . That is, the protective tube 50 of this embodiment is directly fixed to the outer tube 40 . The distal end of the protective tube 50 of this embodiment is fixed to the inner wall of the hollow portion of the distal connector 42 through which the drive shaft 13 passes.

In addition, the protective tube 50 is moved within the inner tube 30 as the inner tube 30 is moved within the outer tube 40, and the drive shaft 13 is passed inside. As shown in FIGS. 3A and 3B, the protective tube 50 of this embodiment extends in the outer tube 40 in the central axis direction (the same direction as the longitudinal direction A) of the outer tube 40 . The protective tube 50 is arranged concentrically with the outer tube 40 within the outer tube 40 . The proximal end of protective tube 50 is an open free end. The drive shaft 13 extends inside the outer tube 40 and inside the protective tube 50 . As the inner tube 30 and the outer tube 40 move relative to each other in the longitudinal direction A, the protective tube 50 moves in the annular space between the inner tube 30 and the drive shaft 13 .

More specifically, when shifting from the pulled-out state shown in FIG. 3A to the pushed-in state shown in FIG. pushed inside. Conversely, when shifting from the pushed state shown in FIG. 3B to the pulled out state shown in FIG. being pulled out. Thus, the protective tube 50 is pushed in and pulled out relative to the inner tube 30 . The drive shaft 13 is likely to bend or meander when pushed in the insertion direction A<b>1 due to, for example, friction between the ultrasonic sensor 60 and the drive shaft 13 and the sheath 20 . By providing the protective tube 50 described above, it is possible to suppress bending and meandering of the drive shaft 13 inside the outer tube 40 compared to a configuration without the protective tube 50 . As a result, bending and breakage of the drive shaft 13 inside the outer tube 40 can be suppressed.

As shown in FIGS. 3A and 3B, the free end, which is the proximal end of the protection tube 50 of the present embodiment, is not only in the pushed state (see FIG. 3B) of the inner tube 30 and the outer tube 40, but also in the pulled state (see FIG. 3B). 3A) is also located within the inner tube 30 . In other words, the protective tube 50 of this embodiment is arranged such that its proximal end is always located within the inner tube 30 . With such a configuration, the portion of the drive shaft 13 that is inside the outer tube 40 but not inside the inner tube 30 can be accommodated inside the protective tube 50 . That is, the protective tube 50 can suppress bending and meandering of the portion of the drive shaft 13 that is likely to bend and meander in the outer tube 40 .

As shown in FIGS. 3A and 3B, the protective tube 50 of this embodiment extends from the distal end of the outer tube 40 beyond the proximal end of the outer tube 40 to the outside of the outer tube 40. However, it is not limited to this configuration.

Although the protective tube 50 of this embodiment is fixed to the outer tube 40, for example, the protective tube 50 itself may not be an independent member but may be configured by a portion integrally connected from the proximal end of the sheath 20.

The protective tube 50 may be formed of, for example, a loosely coiled metal tubular body. By doing so, since the physiological saline solution can flow through the gaps of the coil during priming, it becomes difficult for air to remain in the outer tube 40 . Also, the protective tube 50 may be a tube made of fluororesin such as PTFE instead of metal. Also, the protective tube 50 may be a tubular body in which at least one slit or hole is formed instead of a loosely coiled tubular body. Furthermore, the protection tube 50 may be a composite tube body such as a metal pipe with a hole on the side and a resin tube joined to the metal pipe.

<External Device 120>
As shown in FIG. 1, the external device 120 includes a motor 121 that is a power source for rotating the drive shaft 13 (see FIG. 2, etc.) and a power source for moving the drive shaft 13 in the longitudinal direction A. and a motor 122 . Rotational motion of the motor 122 is converted into axial motion by a ball screw 123 connected to the motor 122 .

More specifically, the external device 120 of the present embodiment includes a drive unit 120a, a control device 120b electrically connected to the drive unit 120a by wire or wirelessly, and the control device 120b connected to the ultrasonic catheter 110. and a monitor 120c capable of displaying an image generated based on the received signal. The motor 121, the motor 122 and the ball screw 123 described above in this embodiment are provided in the drive unit 120a. The operation of the drive unit 120a is controlled by a controller 120b. The controller 120b can be configured by a processor including a CPU and memory.

The external device 120 is not limited to the configuration shown in this embodiment, and may be configured to further include an external input unit such as a keyboard, for example.

Details of the high-rigidity portion 70 of the drive shaft 13 in the ultrasound catheter 110 will be described below with reference to FIGS. 3A, 3B, and 4. FIG.

The drive shaft 13 has a highly rigid portion 70 . A highly rigid portion 70 is provided at the proximal end of the drive shaft 13 . Specifically, the drive shaft 13 is accommodated in the protective tube 50 in a state in which the inner tube 30 is pushed most into the outer tube 40 (see FIG. 3B), and the inner tube 30 is pushed farthest from inside the outer tube 40 . It has a shaft base end portion 13a positioned outside the protection tube 50 in the pulled out state (see FIG. 3A). The drive shaft 13 has a high-rigidity portion 70 on at least a portion of the shaft base end portion 13a. The high-rigidity portion 70 has greater flexural rigidity than the shaft body portion 13b, which is a portion of the drive shaft 13 positioned inside the sheath 20 in the pulled-out state (see FIG. 3A). This "flexural rigidity" can be obtained, for example, from the relationship between the load and deformation of the free end of a test piece of a predetermined length held in a cantilever manner.

In this way, since the high-rigidity portion 70 is provided on at least a part of the shaft base end portion 13a of the drive shaft 13, the shaft base end portion positioned outside the protective tube 50 in the pulled-out state (see FIG. 3A) Bending and meandering at 13a can be suppressed.

Here, as shown in FIG. 3A, in the pulled-out state (see FIG. 3A), the shaft base end 13a is positioned outside the protective tube 50 but still positioned inside the inner tube 30. As shown in FIG. Therefore, the inner tube 30 suppresses bending and meandering of the shaft proximal end portion 13 a when the inner tube 30 is pushed into the outer tube 40 . However, the drive shaft 13 is rotatably accommodated within the inner tube 30 . Therefore, a gap is provided between the shaft base end portion 13a of the drive shaft 13 and the inner tube 30 that surrounds the shaft base end portion 13a. In addition, a gap may be provided from the viewpoint of securing the flow path during priming. In other words, even a portion of the drive shaft 13 located inside the inner tube 30 can bend or meander due to the gap described above. In contrast, by providing the high-rigidity portion 70 in at least a portion of the shaft base end portion 13a, the above-described bending and meandering of the shaft base end portion 13a can be suppressed. As a result, bending and breaking of the shaft base end portion 13a can be suppressed.

FIG. 4 shows the high-rigidity portion 70 of the drive shaft 13 of this embodiment. More specifically, FIG. 4 shows the distal end of the rigid portion 70 of the drive shaft 13 of this embodiment. As shown in FIG. 4 , the high-rigidity portion 70 of the present embodiment includes three layers of coil portions 71 with different winding directions, and a cylindrical body 72 that radially covers the three layers of coil portions 71 . The shaft main body portion 13b (see FIG. 3A) positioned inside the sheath 20 in the pulled-out state (FIG. 3A) is composed of only three layers of coil portions 71. As shown in FIG. That is, the high-rigidity portion 70 of the present embodiment is configured by surrounding the three-layered coil portion 71 integrally connected from the shaft body portion 13b with the cylindrical body 72. As shown in FIG.

The cylindrical body 72 can be composed of, for example, a resin tube or a metal pipe. The bending and meandering of the coil portion 71 accommodated inside the cylindrical body 72 is restricted by contacting the inner surface of the cylindrical body 72 . The proximal end of the cylindrical body 72 of this embodiment is fitted into the hollow portion of the hub 32 (see FIG. 3A etc.) of the inner tube 30 . That is, the proximal end portion of the cylindrical body 72 of this embodiment is fixed by being sandwiched between the inner walls of the hollow portion of the hub 32 with the drive shaft 13 accommodated therein. That is, the proximal end of drive shaft 13 and the proximal end of barrel 72 are fixed to hub 32 of inner tube 30 .

As described above, the high-rigidity portion 70 is accommodated in the protective tube 50 in the pushed state (see FIG. 3B), and is located outside the protective tube 50 in the pulled-out state (see FIG. 3A). It suffices if it is provided at least partly. In other words, the cylindrical body 72 of the present embodiment may be provided at least partially on the shaft base end portion 13a. However, as in the present embodiment, the drive shaft 13 has at least the length of the radius of the inner diameter of the inner tube 30 in the axial direction of the drive shaft 13 (the same direction as the longitudinal direction A) of the shaft base end portion 13a. It is preferable to provide a high-rigidity portion 70 in an area equal to or longer than the length minus (see symbol "r" in FIG. 3A). That is, in the present embodiment, the cylindrical body 72 is at least as long as the radius of the inner diameter of the inner tube 30 in the shaft axial direction of the drive shaft 13 (see symbol "r" in FIG. 3A). It is provided in an area equal to or longer than the length minus By doing so, the bending and meandering of the shaft base end portion 13a can be further suppressed. As a result, bending and breakage of the shaft base end portion 13a can be further suppressed. The “inner tube inner diameter” means the inner diameter of the portion of the inner tube that is inserted into the outer tube, and means the inner diameter r of the inner tube main body 31 of the inner tube 30 in this embodiment.

Furthermore, as in the present embodiment, it is more preferable that the drive shaft 13 has the high rigidity portion 70 over the entire area of the shaft base end portion 13a in the shaft axial direction. That is, in the present embodiment, the cylindrical body 72 is provided over the entire area of the shaft base end portion 13a in the shaft axial direction. By doing so, the bending and meandering of the shaft base end portion 13a can be further suppressed. As a result, bending and breakage of the shaft base end portion 13a can be further suppressed.

Further, when the shaft base end portion 13a described above is referred to as the “proximal side shaft base end portion 13a”, the drive shaft 13 can be pushed in (see FIG. 3B) and pulled out (FIG. 3A) as in the present embodiment. ), it is preferable to further include a high-rigidity portion 70 in at least a portion of the distal shaft base end portion 13 c housed in the protective tube 50 . In other words, in the present embodiment, the cylindrical body 72 is provided not only at the proximal shaft base end portion 13a but also at the distal shaft base end portion 13c. More specifically, the cylindrical body 72 of the present embodiment covers the entire area of the proximal shaft base end 13a in the shaft axial direction and the proximal shaft base end 13a of the distal shaft base end 13c. It is provided over a region in the shaft axial direction of a portion that is continuous to the distal side. In other words, the distal end of the cylindrical body 72 of this embodiment is located within the protective tube 50 even in the drawn state (see FIG. 3A). By doing so, when the pulled-out state (see FIG. 3A) shifts to the pushed-in state (see FIG. 3B), the distal end of the high-rigidity portion 70 moves toward the free end, which is the proximal end of the protective tube 50. I don't get caught. Therefore, bending and meandering of the proximal shaft base end portion 13a can be further suppressed. As a result, bending and breaking of the proximal shaft base end portion 13a can be further suppressed.

Furthermore, the drive shaft 13 of this embodiment does not include the high-rigidity portion 70 at the portion positioned inside the sheath 20 in the pushed state (see FIG. 3B). That is, the high-rigidity portion 70 is formed at a position where it does not enter the sheath 20 in the pushed state (see FIG. 3B). More specifically, the distal end of the high-rigidity portion 70 of the drive shaft 13 of this embodiment is located within the outer tube 40 in a pushed state (see FIG. 3B). By doing so, even if the bending rigidity of the high-rigidity portion 70 is higher than the bending rigidity of the sheath 20, the high-rigidity portion 70 enters the sheath 20 and the posture of the sheath 20 changes to the high-rigidity portion. It is possible to prevent the change along the posture of 70 . As a result, positional fluctuation of the ultrasonic sensor 60 within the sheath 20 can be suppressed. Moreover, bending of the sheath 20 at the distal end of the high-rigidity portion 70 can be suppressed. In other words, in the ultrasound catheter 110 of this embodiment, the bending rigidity of the high-rigidity portion 70 of the drive shaft 13 may be higher than the bending rigidity of the sheath 20 .

As described above, the high-rigidity portion 70 of the present embodiment is composed of the three-layered coil portion 71 and the cylindrical body 72, but is not limited to this configuration. 5 to 7 are diagrams showing modified examples of the high-rigidity portion 70. FIG.

The high-rigidity portion 70 shown in FIG. 5 includes a three-layered coil portion 71 and a laminated reinforcing portion 73 that is joined to the outer peripheral surface of the coil portion 71 and laminated on the outer peripheral surface of the coil portion 71 . In this manner, the high-rigidity portion 70 may include a laminated reinforcement portion 73 joined to the outer peripheral surface of the coil portion 71 instead of or in addition to the cylindrical body 72 (see FIG. 4). The lamination reinforcing portion 73 can be made of wax or various resins, for example. The three-layered coil portion 71 is reinforced by the laminated reinforcing portion 73 to increase strength and bending rigidity. A method of joining the laminated reinforcing portion 73 to the outer peripheral surface of the coil portion 71 is not particularly limited. The laminated reinforcing portion 73 may be joined to the outer peripheral surface of the coil portion 71 by adhesion, welding, application, coating, or the like, for example.

A high-rigidity portion 70 shown in FIG. 6 includes a three-layered coil portion 71 and a core member 74 inserted inside the coil portion 71 . In this manner, the high-rigidity portion 70 includes the core member 74 inserted into the coil portion 71 instead of or in addition to the cylindrical body 72 (see FIG. 4) and the laminated reinforcing portion 73 (see FIG. 5). You may prepare. The core member 74 can be made of metal or resin, for example. Deflection and meandering of the coil portion 71 are restricted by contact with the outer surface of the core member 74 .

The high-rigidity portion 70 shown in FIG. 7 is composed of three layers of coil portions 75 . However, each coil of the coil portion 75 constituting the high-rigidity portion 70 shown in FIG. 7 has a larger cross-sectional dimension than each coil of the three-layered coil portion 71 located on the distal side thereof. In the example shown in FIG. 7 , a three-layer coil portion 71 located on the distal side and a three-layer coil portion 75 as the high-rigidity portion 70 located on the proximal side are joined by a joint portion 76 . . The joining portion 76 is not particularly limited as long as it is configured to join the coil portion 71 and the coil portion 75, such as a welding portion or an adhesive.

In FIG. 7, the difference in bending rigidity is achieved by varying the cross-sectional dimensions of the coils. may be realized.

7 further includes at least one of a tubular body 72 (see FIG. 4), a laminated reinforcing portion 73 (see FIG. 5), and a core member 74 (see FIG. 6). may

In this way, the configuration of the high-rigidity portion 70 is not particularly limited as long as it has higher bending rigidity than the shaft body portion 13b, which is the portion located inside the sheath 20, in the pulled-out state (see FIG. 3A).

The diagnostic imaging catheter according to the present disclosure is not limited to the specific configurations shown in the above-described embodiments and modifications, and various modifications, changes, and combinations are possible without departing from the scope of the claims. For example, FIG. 3A and FIG. 3B show a configuration in which one high-rigidity portion 70 that is continuous in the shaft axial direction is provided at the proximal shaft base end portion 13a, but the configuration is not limited to this. As shown in FIGS. 8A and 8B, the proximal shaft base end portion 13a may be provided with a plurality of high-rigidity portions 70 intermittently arranged in the axial direction of the shaft. However, as in the above-described embodiment, the high-rigidity portion 70 extends distally from within the hub 32 of the inner tube 30 and is positioned at the proximal end of the protective tube 50 in the pulled-out state (see FIG. 3A). It is preferable to have a continuous configuration up to the position in the vicinity or in the protective tube 50 as in the above-described embodiment. By doing so, the bending and meandering of the proximal shaft base end portion 13a can be more reliably suppressed.

The present disclosure relates to diagnostic imaging catheters.

10: Ultrasonic probe 13: Drive shaft 13a: Proximal side shaft base end (shaft base end)
13b: Shaft main body portion 13c: Distal side shaft base end portion 14: Electric signal line 20: Sheath 20a: Main body portion 20b: Guide wire insertion portion 30: Inner tube 31: Inner tube main body 31a: Distal end of inner tube main body Part 32: Hub 32a: Hub distal end surface 40: Outer tube 41: Outer tube body 42: Distal side connector 43: Proximal side connector 43a: Proximal end surface 43b: Abutment wall 50: Protective tube 60: Ultra Sound wave sensor (an example of an image sensor)
70: High-rigidity portion 71: Coil portion 72: Cylindrical body 73: Laminated reinforcement portion 74: Core member 75: Coil portion 76: Joint portion 100: Diagnostic imaging device 110: Ultrasonic catheter (an example of diagnostic imaging catheter)
110a: Insertion section 110b: Operation section 120: External device 120a: Drive unit 120b: Control device 120c: Monitors 121, 122: Motor 123: Ball screw A: Longitudinal direction of diagnostic imaging catheter (longitudinal direction of sheath)
A1: Insertion direction A2: Removal direction r: Radius of the inner diameter of the inner tube

Claims

a sheath inserted into the body cavity;
a drive shaft inserted within the sheath;
an image sensor secured to the distal end of the drive shaft;
an outer tube secured to the proximal end of the sheath;
an inner tube that houses the proximal end of a drive shaft and is movable within the outer tube with the drive shaft;
a protective tube fixed to the proximal side of the sheath, moved within the inner tube as the inner tube moves within the outer tube, and passing the drive shaft therein;
The drive shaft is accommodated in the protective tube in a pushed state in which the inner tube is most pushed into the outer tube, and is positioned outside the protective tube in a drawn state in which the inner tube is pulled out from the outer tube. A catheter for diagnostic imaging, comprising a high-rigidity portion having greater flexural rigidity than the portion positioned within the sheath in the pulled-out state, at least a part of the proximal end portion of the shaft.
The drive shaft includes the high-rigidity portion in a region of the shaft base end that is equal to or longer than at least the length of the radius of the inner diameter of the inner tube in the axial direction of the drive shaft. The diagnostic imaging catheter according to claim 1 .
The diagnostic imaging catheter according to claim 2, wherein the driving shaft includes the high-rigidity portion over the entire area of the shaft base end in the shaft axial direction.
When the shaft base end is the proximal shaft base end, the driving shaft is attached to at least a part of the distal shaft base end accommodated in the protective tube in the pushed state and the pulled out state. 4. The diagnostic imaging catheter according to any one of claims 1 to 3, further comprising the high-rigidity portion.
The diagnostic imaging catheter according to any one of claims 1 to 4, wherein the drive shaft does not have the high-rigidity portion at a portion positioned inside the sheath in the pushed state.