JPH0970403A - Ultrasonic catheter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve bendability and flexibility between a rigid part including a vibrator on a tip side and an elastic member at the tip of a catheter and to improve operability. SOLUTION: This ultrasonic catheter 1 is provided with an exterior shaft 2, a driving shaft 6 inserted to the inside of the exterior shaft 2 and a housing 27 fixed to the driving shaft 6 so as to be positioned at the tip side inner part of the exterior shaft 2. The driving shaft 6 is rotated by an external drive source. The exterior shaft 2 is provided with a coil-like first elastic member 41 on the tip and the housing 27 is provided with a second elastic member 19 on a tip part. The tip of the second elastic member 19 is intruded into the first elastic member 41.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an ultrasonic catheter used by being inserted into a body cavity such as a blood vessel or a blood vessel.

[0002]

2. Description of the Related Art Conventionally, there has been known an ultrasonic catheter which is inserted into a thin blood vessel such as a coronary artery of a heart or a blood vessel such as a bile duct to display a sectional image of a lumen or to measure a blood flow.
In this ultrasonic catheter, for example, as shown in FIG. 17 or 18, the ultrasonic transducer 3 and the transducer 3 directly or with the ultrasonic reflection plate 4 are provided inside the distal end of a hollow catheter shaft 2 inserted into a body cavity. A drive transmission shaft 6 that transmits a driving force to rotate, a signal line 7 that connects the vibrator 3 and an external electric circuit 5 are built in, and the drive shaft is mechanically driven by an external drive source 8 to generate ultrasonic waves. Ultrasonic catheters for scanning are known.

[0003]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention In a catheter to be inserted into a blood vessel, in order to improve the running property in the blood vessel,
It is preferable that the tip end is softer. Further, it is preferable that the tip of the catheter can be easily confirmed under fluoroscopy. For this reason, there is a catheter in which contrast is added to the catheter body in order to know the position of the catheter. There is also a catheter having a contrasting flat plate, a ring-shaped metal, a coil-shaped metal or the like at the distal end thereof. As shown in FIGS. 17 and 18, some ultrasonic catheters have a metallic member having coiled elasticity or a metal piece 14 for contrast enhancement attached to the distal end of the catheter. Further, in the ultrasonic catheter, the portion 12 of the catheter shaft 2 that transmits and receives ultrasonic waves is an olefin resin or a fluorine resin having excellent ultrasonic permeability, and since the thinner the wall, the better the ultrasonic permeability, 100 μm or less. Is formed by. Therefore, the mechanical strength of this portion 12 is lower than that of the shaft 15 on the proximal side of the catheter, and it is easy to kink. Further, the ultrasonic catheter has a rigid portion such as an ultrasonic transducer. Therefore, the mechanical characteristics of the catheter do not change smoothly between the rigid portion such as the vibrator 3 and the distal end portion of the catheter shaft 2 including the coil-shaped elastic member, good bending cannot be performed, and kink easily occurs. The operability of the sonic catheter was poor.

Japanese Patent Publication No. 5-507219 discloses an ultrasonic catheter in which a housing is fixed to an exterior shaft of a catheter, and an elastic member is connected to the tip of the housing. In this catheter, the rigid housing portion is long, and the tip portion of the catheter including the housing portion has poor flexibility and bendability.

From the viewpoint of flexibility, it can be said that the catheter of the type shown in FIG. 17 which does not have a fixed housing is excellent.

An object of the present invention is to provide an ultrasonic catheter having improved operability by improving the flexibility and flexibility between the rigid portion including the transducer on the distal end side and the elastic member at the distal end of the catheter.

[0007]

[Means for Solving the Problems] What achieves the above object is to provide an exterior shaft to be inserted into a body cavity, and to insert a mechanical drive force into the exterior shaft from the proximal side to the distal side. A drive shaft, an ultrasonic oscillator or both an ultrasonic oscillator and an ultrasonic reflector, and a housing fixed to the drive shaft so as to be located inside the tip side of the exterior shaft, An ultrasonic catheter having a drive shaft rotatable by an external drive source, wherein the exterior shaft includes a coil-shaped first elastic member at a distal end portion thereof, and the housing has a distal end portion extending toward a distal end side of the catheter. The ultrasonic catheter is provided with two elastic members, and the tip of the second elastic member is located inside the first elastic member.

The length of the portion of the second elastic member that has penetrated into the first elastic member is preferably 0.5 mm to 20 mm. The second elastic member is preferably a coil-shaped elastic member. The second elastic member is
It is preferable that at least a part is formed of a super elastic metal. It is preferable that the exterior shaft includes a tube forming a reinforcing layer, and a spiral slit is provided at a tip portion of the tube. The first elastic member may include an opening that connects the inside and the outside of the catheter. The first elastic member is preferably made of a high X-ray contrast material. It is preferable that the second elastic member is formed in a tapered shape whose diameter decreases toward the tip side. It is preferable that the first elastic member is formed in a tapered shape whose diameter decreases toward the tip side. The first elastic member preferably includes a support member inside.

In addition, what achieves the above-mentioned object is that a catheter used by being inserted into a body cavity has a built-in drive shaft for transmitting a mechanical driving force from the proximal side to the distal side, and the catheter is superposed inside the distal side. Connecting a housing provided with an ultrasonic transducer and / or an ultrasonic reflector to the drive shaft,
An ultrasonic catheter in which the drive shaft is rotated by an external drive source, wherein the catheter has a coil-shaped first elastic member of one or more layers at the tip thereof, which is connected to the tip of the housing and the catheter tip. Second extending to the side
Is an ultrasonic catheter in which the second elastic member is inserted into the first elastic member.

Further, the insertion length of the second elastic member inserted into the first elastic member is preferably 0.5 mm to 20 mm. It is preferable that the second elastic member is formed in a coil shape having one or more layers. It is preferable to provide a round bar or flat plate-shaped support member inside the second elastic member formed in a coil shape. Further, it is preferable to use a super elastic metal for at least a part of the second elastic member. Further, it is preferable to fix the first elastic member portion so that liquid can flow inside and outside the catheter. Further, it is preferable to use a metal capable of X-ray contrast as the first elastic member. Further, it is preferable that the second elastic member is formed in a taper shape and has a smaller diameter toward the tip end side of the catheter. Further, it is preferable that the first elastic member is formed in a taper shape and has a smaller diameter toward the tip. Further, it is preferable that the first elastic member is fixed to the tip end so that a round bar or a flat plate-shaped support member is provided inside.

Further, what achieves the above-mentioned object is provided with an exterior shaft having an outer layer and an inner layer, a drive shaft inserted into the exterior shaft, and an ultrasonic vibrator, and the inside of the tip side of the exterior shaft is provided. A housing fixed to the drive shaft so as to be positioned, a first elastic member positioned at a tip of the exterior shaft and inserted between the outer layer and an inner layer, and a tip of the housing. A second elastic member fixed to the distal end of the catheter, the distal end of the second elastic member being located inside the first elastic member. .

Further, it is preferable that the exterior shaft has a tip member fixed to the tip thereof and having an opening.

Further, the armored shaft has a closed tip member fixed to its tip, and the catheter is
It may have an internal space that is closed and filled with liquid.

Further, it is preferable that the main body of the exterior shaft has a reinforcing layer located between the exterior and the inner layer.

Further, it is preferable that the first elastic member and the reinforcing layer do not exist on the exterior shaft of the portion where the housing is located.

Further, it is preferable that the tip portion of the reinforcing layer has a spiral slit.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An ultrasonic catheter according to the present invention will be described with reference to the drawings.

The ultrasonic catheter 1 of the present invention has an exterior shaft 2 inserted into a body cavity, a drive shaft 6 inserted into the exterior shaft 2, a housing 27 fixed to the tip of the drive shaft 6, and an exterior. It has a hand operation part (connector) 20 fixed to the base end of the shaft 2.

FIG. 1 shows an ultrasonic catheter device 10 in which an external unit 13 is connected to the ultrasonic catheter 1.
It is.

Inside the distal end side of the exterior shaft 2 of the catheter, there is housed a housing 27 which houses a transducer 11 having an ultrasonic transducer function for transmitting and receiving ultrasonic waves. The housing 27 is connected to the tip of the coil-shaped drive shaft 6.

The drive shaft 6 is made of stainless steel (SUS).
304, SUS316, etc.) is formed by winding two layers of two flat plates. Drive shaft is 0.4k
It preferably has a breaking strength of gf or more. The drive shaft 6 may be a wire or plate-shaped metal or resin coiled or blade-wrapped in a single layer or multiple layers. The drive shaft has a breaking strength of 0.4 kg.
A signal wire to be described later may be wound horizontally on the wire of f or more.

In the drive shaft 6, as shown in FIGS. 2 and 9, a signal line 7 (7a, 7a, consisting of two lead wires) is provided.
7b) is built in. The distal end side of the catheter of the signal line 7 is connected to a transducer formed on the transducer 11, and the proximal end side (hand side) is connected to the terminals 21 and 2 of the hand operation unit 20.
Connected to 2. Specifically, as shown in FIG.
At the rear end of the drive shaft 6, a cylindrical member made of an insulating material is inserted and fixed. The terminal 22 is fixed to the end of the cylindrical member, and the terminal 21 is fixed to the side surface slightly on the shaft 6 side from the end of the cylindrical member. The base end of the signal line 7 a is connected to this terminal 22. Further, the base end of the signal line 7b is connected to the terminal 21 through an opening formed in the side surface of the cylindrical member.

As shown in FIGS. 2 and 9, the hand-side operation portion (connector) 20 is a locking portion 13 of the external unit 13.
It has a projection 25 that engages with a, and both are detachably connected.

The external unit 13 is provided with a drive source 8 including a transmitting / receiving circuit 5 and a motor 16. The external unit 13 is also electrically connected to the console 3 having a signal processing circuit and an image display device.

The motor 16 as an external drive source has a rotating body (rotating plate) 16a, and a first cylindrical terminal 24 is fixed to the center of the rotating plate 16a.
A second tubular terminal 23 is fixed to a so as to surround the first terminal 24 without contacting it.
These cylindrical terminals 23 and 24 rotate as the rotary plate rotates.

In the external unit 13, a rotary sliding terminal portion 2 composed of a slip ring or the like connected to the transmitting / receiving circuit 5 is provided.
6. The terminal portion 26 has a first terminal 26a and a second terminal 26b. The first terminal 26a contacts the second tubular terminal 23 of the rotary plate, and the second terminal 26b contacts the first tubular terminal 24 of the rotary plate. The contact between these terminals is maintained even when the rotary plate is rotated.

The rod-shaped terminal 22 on which the drive shaft 6 is fixed
Engage with the opening of the first cylindrical terminal 24 of the rotating plate.
The base end portion (terminal 21) of the drive shaft 6 is the second end of the rotary plate.
Of the tubular terminal 23 and engages with an annular rib provided near the opening of the tubular terminal 23. Thereby, the drive shaft 6 is detachably connected to the rotating plate of the motor 16. Then, the rotational force of the motor is transmitted to the drive shaft via the rotary plate and the two tubular terminals 23 and 24.

As shown in FIGS. 14 and 15, the housing 27 has a pipe shape having an outer diameter substantially equal to that of the drive shaft 6, and a central portion thereof is cut in a predetermined length axial direction and approximately half of an arc is cut off. As a result, the fixed portion 18 of the transducer 11 is formed. As a material for forming the housing 27, metal, resin, ceramics or the like is used. The material for forming the housing 27 is made of stainless steel (SUS30) from the viewpoint of bonding strength and reinforcement of the transducer 11.
4, SUS316) and the like, and ceramic materials such as alumina and zirconia are preferable.

At the tip of the catheter 1 (the tip of the exterior shaft), a single layer of coil-shaped first elastic member 41 is provided. The second elastic member 19 is connected to the distal end portion of the housing 27 and extends toward the distal end side of the catheter. The second elastic member 19 extends into the first elastic member and reinforces the first elastic member 41. In other words, the tip of the second elastic member 19 is located inside the first elastic member 41.

The second elastic member 19 is made of stainless steel (S
US304, SUS316, etc.) elastic metal,
A rod-shaped body formed of a superelastic metal such as a NiTi alloy or a resin such as polyacetal is used. The elastic member 19 is preferably made of a super elastic material such as NiTi alloy from the viewpoint of the connection strength with the housing 27 and the elasticity of the elastic member 19 itself. The second elastic member 19 is connected to the tip of the housing 27 by adhesion, brazing, welding or the like. The elastic member 19 is attached to the coil-shaped elastic member 41 connected to the inside of the exterior shaft 2 of the catheter by 0.5 mm-2.
It is preferable to penetrate about 0 mm.

The first elastic member 41 is fixed with its base end portion being inserted into the distal end opening of the exterior shaft 2. Coil-shaped elastic member 41 and outer shaft tip side 12
The length of the connecting portion is preferably as short as possible in the range where sufficient connecting strength is obtained, and is preferably about 0.5 mm to 10 mm. Further, the coil-shaped elastic member 41 is formed in a taper shape and has a smaller diameter toward the tip side.

Coil-shaped elastic member 41 at the tip of the catheter
Can be made of the same material as the elastic member 19.
As a material for forming the elastic member 41, a metal such as Pt, Ir, Au or an alloy material thereof is preferable from the viewpoint of X-ray contrast.

In the ultrasonic catheter according to the present invention, the tip end of the rod-shaped elastic member 19 is always located in the coil-shaped elastic member 41 even when the catheter is bent, so that the outer shaft 12 of the catheter alone is used. Flexibility and kink resistance between the housing 27 and the coil-shaped elastic member 41 at the distal end of the catheter are improved as compared with the conventional one.

In particular, by providing the second elastic member 19 which reaches the inside of the first elastic member 41 from the distal end of the housing 27, the portion where the physical properties change abruptly from the distal end of the housing 27 to the distal end side of the catheter. Is not formed, and the flexibility at the tip of the catheter is improved.

The exterior shaft 2 of the catheter comprises an ultrasonic transmission / reception portion 12 on the tip side and an exterior shaft body portion 1 on the proximal side.
5 may be made of a different material. The outer shaft 2 or the shaft body 15 is made of a so-called catheter material such as a polyolefin-based, polyurethane-based, polyacetal-based, polyimide-based, or fluorine-based resin tube, a metal tube such as stainless steel (SUS304, SUS316, etc.), a NiTi-based alloy. Etc., super elastic metal tube, resin and stainless steel (SUS304, SUS)
316) and the like, and a composite tube in which a wire is coiled or braided is used. Shafts 2, 1
The wall thickness of No. 5 is 30 to 300 μm and is at least 0.
It is desirable to have a tensile breaking strength of 4 kgf or more. The ultrasonic wave transmitting / receiving portion 12 on the tip side of the catheter is made of a polyolefin type, polyurethane type, or
Fluorine-based resins are preferred. The thickness of the resin forming the sending / receiving part 12 is preferably about 10 to 100 μm. Further, hydrophilic resin, fluororesin, silicone resin or the like is provided on the outer and inner surfaces (in particular, the outer surface) of the exterior shaft 1 in a range of 1 μm to several tens.
It may be coated with μm. By these processes, the sliding resistance of the outer and inner surfaces of the exterior shaft 2 can be reduced. Also,
The outer surface of the outer shaft may be coated or fixed with an antithrombotic substance. The coating of the antithrombotic substance is performed, for example, by coating the outer surface of the shaft with a resin containing heparin.

FIG. 3 is a sectional view showing the structure of the transducer 11 used in the ultrasonic catheter 1 of the present invention. The transducer 11 has an ultrasonic transducer 3. The vibrator transmits and receives ultrasonic waves. The vibrator 3 has electrodes 32 on both sides of a piezoelectric body 31 such as a rectangular PZT.
Is formed by a method such as vapor deposition or printing. The shape of the piezoelectric body 31 may be circular. In order to absorb or attenuate ultrasonic waves on the back surface side of the vibrator 3, a resin or resin such as epoxy, urethane, acrylic resin or a back material 33 in which metal or inorganic powder is mixed is provided. The back material 33 has a thickness difference D on the back side as shown in FIG.
Is provided as λ / 4 (where λ is the wavelength in the backing material at the transmission frequency), so that the backing material is provided so that the reflected wave from the back surface of the backing material 33 is canceled by interference. As shown in FIG. 3B, the backing material is a low acoustic impedance layer 36 (Z = 8 × 10 ⁶ Kg).
/ M ² s or less) and the high impedance layer 37 (Z = 20)
The influence of the reflected wave from the back surface of the backing material 33 may be reduced by alternately laminating (× 10 ⁶ kg / m ² s or more).

A so-called acoustic matching layer 35 is provided on the acoustic radiation surface of the vibrator 3. The acoustic matching layer 35 is formed to have a thickness of λ / 4 (λ is the wavelength in the matching layer at the transmission frequency). The acoustic matching layer 35 is only one layer in the illustrated one, but may be two or more layers.

Next, an ultrasonic catheter 30 according to another embodiment of the present invention will be described with reference to FIGS. 4, 5 and 6. The basic configuration of the ultrasonic catheter 30 is shown in FIG.
2 and is the same as the ultrasonic catheter 1 described above.

In the ultrasonic catheter 30 of this embodiment,
The transducer 11 is fixed to the housing 27 with an adhesive or the like so that the ultrasonic wave transmitting / receiving surface has a deviation of about ± 10 ° in the direction perpendicular to the axial direction of the ultrasonic catheter 11. The housing 27 is fixed to the distal end of the drive shaft 6 by bonding, brazing or welding so that the bonding strength is at least 0.4 Kgf or more.

In the ultrasonic catheter 30 of this embodiment,
A coil-shaped elastic member 19 is connected to the tip of the housing 27 so as to be tapered so as to have a smaller diameter toward the tip of the catheter. Coil-shaped elastic member 19
Is a single-layer or multi-layer, and a single-strand or multi-strand coil body is used. When a multilayer coil body is used as the elastic member 19, it is preferable that the winding direction of the outermost layer coil is set to a direction that is loosened with respect to the rotation direction of the drive shaft. When a one-layer coil body is used as the elastic member 19, it is preferable that the winding direction of the coil is a direction loosened with respect to the rotation direction of the drive shaft. FIG. 4 shows a case where the coil is a single layer and is rotated clockwise. The elastic member 19 extends so as to be inserted into the coil-shaped elastic member 41 attached to the tip of the exterior shaft by about 0.5 mm to 20 mm. Coil-shaped elastic member 19
The materials of 41 and 41 are the same as described above.

Signal lines 7a and 7b are connected to the electrodes 32a and 32b on both sides of the vibrator 3. Although the signal line 7 is a stranded wire in FIG. 4, it may be a coaxial wire.

The outer surface of the distal end of the proximal side (main body) 15 is gradually thinned toward the distal end at the connecting portion between the proximal side (shaft main body) 15 and the distal side (shaft distal end) 12 of the catheter. Is processed into a taper shape,
The inner surface of the base end portion of the front end side (front end portion) 12 is tapered so that the inner surface becomes gradually thinner toward the base end side.
The tip of the body portion 15 formed in this way is
A connecting portion is formed by intruding into the base end of and joining. By forming in this way, the connection portion,
The outer diameters are almost the same. Furthermore, by doing so, the length of the connection portion can be made relatively long, the strength of the connection portion is high, and the mechanical characteristics of the connection portion change sequentially without a sudden change point, Flexibility and flexibility of the exterior shaft 2 at the connection portion are improved.

At the tip of the ultrasonic catheter 30, a resin film 17 is provided to cover the step portion between the tip portion 12 of the shaft and the elastic member 41 and the portion of the elastic member 41 protruding from the tip portion 12 of the shaft. This resin film 17
The front end of the elastic member 41 is tapered like the front end of the elastic member 41. The resin film 17 assists in maintaining the shape of the tip of the elastic member 41. As the resin film 17,
Soft synthetic resin such as silicone rubber, polyurethane, olefin elastomer, polyamide elastomer, etc. can be used.

As shown in FIGS. 5 and 6, in the cylindrical housing 27, the transducer housing portion 18 formed by cutting out a half of an arc in the vicinity of the center in the direction of the predetermined length axis is formed. Have. Transducer 11
The acoustic matching layer 35 side is the transducer housing 18
Is accommodated in the accommodating portion such that the rear surface 33 is on the bottom side of the transducer accommodating portion 18. The transducer 11 is fixed to the housing 27 with an adhesive.

Next, the ultrasonic catheter 40 of the embodiment shown in FIG. 7 will be described.

In the ultrasonic catheter 40 of this embodiment,
A stainless steel (SUS30
4, SUS316, etc.), and a coil-shaped elastic member 19 made of a metal such as a NiTi alloy is attached. A coil-shaped member 41 having a contrast property is attached to the inside of the tip portion 12 of the exterior shaft by an adhesive agent 42. The tip of the elastic member 19 is formed so as to be inserted inside the coil-shaped member 41. The tip of the elastic member 19 is
It is tapered so that the diameter decreases toward the tip.

The tip of the coil-shaped member 41 is tapered so that its diameter decreases toward the tip. Coiled member 4
A round wire or at least a part of a flat plate-shaped support member 43 is attached to the inside of the front end side of 1. This support member 4
3 is stainless steel (SUS304, SUS316
Etc.), a metal such as a NiTi alloy, or the like. The support member 43 improves the mechanical strength and flexibility of the coil 41. The support member 43 has a hemispherical tip portion 43a, a connecting portion 43b extending from the hemispherical tip portion 43a while expanding its diameter rearward, and a disc portion 43c formed at a rear end portion of the connecting portion 43b. The outer peripheral surface of the disk portion 43c is engaged with the inner surface of the coil-shaped member 41. The tip of the coil-shaped member 41 is in contact with the rear end surface of the hemispherical connecting portion 43a.

The structure of the exterior shaft is not limited to that described above, and may be, for example, that shown in FIG. FIG. 8 is a partial sectional view of a modified example of the exterior shaft used in the ultrasonic catheter of the present invention.

In this exterior shaft 2, the exterior shaft (main body) 15 on the near side has a two-layer structure including an inner layer 48 and an outer layer 49. The tip side 12 including the ultrasonic wave transmitting / receiving portion of the shaft 2 has a single-layer structure including only the outer layer 49. The inner layer 48 on the hand side (main body) 15 is formed by winding a metal tube of stainless steel (SUS304, SUS316, etc.) or the like, a super elastic metal tube of NiTi alloy, or a stainless steel (SUS304, SUS316, etc.) wire or coil winding. It is formed by a tube or the like. The outer layer 49 is formed of a resin such as a polyolefin-based resin, a fluorine-based resin, or a polyamide. The outer layer 49 is formed by inserting a tube body serving as an inner layer into a heat-shrinkable tube serving as an outer layer, heating the heat-shrinkable tube to thermally shrink the heat-shrinkable tube, and coating the inner layer tube with a solvent. Insert the tube body to be the inner layer in the swollen one and dry it to shrink the resin tube to coat the inner layer tube with the heat-shrinkable tube, the method to coat the inner layer tube with the resin to be the outer layer by dipping, It is carried out by a method of melt-extruding a resin to be the outer layer onto the outer surface of the tube to be the inner layer and coating the tube to be the inner layer.

The structure of the ultrasonic catheter of the present invention will be described below from another point of view.

1 and 2 show an ultrasonic catheter 1 according to the first embodiment of the present invention. FIG. 1 shows an axial cross-section of an ultrasonic catheter of the present invention and a configuration diagram of a system, and FIG. 2 is a partial axial cross-sectional view showing a hand operation unit and an external unit of the ultrasonic catheter of the present invention.

A housing 27 having a transducer 11 for transmitting and receiving ultrasonic waves is built into the distal end side of the exterior shaft 2 of the catheter 1, and the housing 27 is connected to the distal end of a coiled drive shaft 6. The drive shaft 6 incorporates a pair of twisted signal lines 7, the catheter tip side of the signal line 7 is connected to a transducer formed on a transducer 11, and the hand side is a terminal 21 of a hand operation unit 20,
22. The hand operation part 20 is detachably connected to the locking part 25 of the external unit 13. The terminals 21 and 22 in the hand operation part 20 are electrically connected to the transmission / reception circuit 5 via a rotary sliding terminal 26 such as a slip ring, and the driving force from the motor 16 is applied to the drive shaft 6.
Is connected to the terminals 23 and 24 of the external drive source 8 so as to be detachable. The external unit 13 includes a drive source 5 including a transmission / reception circuit 5 and a motor 16. The external unit 13 is also electrically connected to the console 3 having a signal processing circuit and an image display device.

The housing 27 has an outer diameter of the drive shaft 6
It has a pipe shape almost equal to
The fixed portion 18 is removed inside in a rectangular shape. The material may be metal, resin or ceramics, but from the viewpoint of joining strength and reinforcement of the transducer 11, stainless steel (S
US304, SUS316, etc.) and ceramic materials such as alumina, zirconia, etc. are preferable.

At the distal end of the catheter 1, a single layer of coil-shaped first elastic member 41 is provided.
A second elastic member 19 is connected to the tip of the catheter 1 and extends toward the tip of the catheter 1. Here, the second elastic member 19
Extends into the first elastic member and reinforces the first elastic member 41.

At the tip of the housing 27, a rod-shaped elastic member 19 made of an elastic metal such as stainless steel (SUS304, SUS316, etc.), a superelastic metal such as NiTi alloy, or a resin such as polyacetal is adhered or brazed. ,
The elastic member 19 is connected by welding or the like, and extends so as to be inserted into the coil-shaped elastic member 41 connected to the inside of the exterior shaft 2 of the catheter by about 0.5 mm to 20 mm (insertion length). The connection length between the coil-shaped elastic member 41 and the outer shaft front end side 12 is preferably as short as possible in a range where sufficient connection strength is obtained, and is 0.5 mm to 10 mm.
The degree is preferred.

Further, the coil-shaped elastic member 41 is formed in a taper shape, and has a smaller diameter on the front end side. Elastic member 1
9 is preferably a superelastic material such as a NiTi alloy because of its connection strength with the housing 27 and elasticity of the elastic member 19 itself. The coil-shaped elastic member 41 at the tip of the catheter is made of the same material as that of the elastic member 19, but in view of X-ray contrast, P
A metal such as t, Ir, Au or an alloy material thereof is preferable. According to the present invention, since the rod-shaped elastic member 19 is always inserted in the coil-shaped elastic member 41 even when the catheter is bent, the bendability between the housing 19 and the coil-shaped elastic member 41 at the catheter tip portion, The kink resistance is improved as compared with the case where only the exterior shaft 12 of the conventional catheter is used, and the flexibility of the ultrasonic catheter 1 can be gradually changed to the catheter tip softly and smoothly.

The outer sheath shaft 2 of the catheter may be made of a different material depending on the ultrasonic transmission / reception portion 12 on the distal end side and the outer sheath shaft portion 15 on the proximal side. , Polyurethane-based, polyacetal-based, polyimide-based, fluorine-based resin tubes and stainless steel (SUS
304, SUS316, etc.) metal tube, NiTi
A super-elastic metal tube such as a system alloy, or a composite tube in which a resin and a wire such as stainless steel (SUS304, SUS316, etc.) is coiled or braided,
The wall thickness is 30 to 300 μm, and the tensile breaking strength is preferably at least 0.4 Kgf or more. Further, as shown in the catheter 1, the ultrasonic wave transmitting / receiving portion 12 on the catheter tip side is preferably made of a polyolefin-based resin, a polyurethane-based resin, or a fluorine-based resin excellent in ultrasonic wave permeability, and has a wall thickness of 10 to 10.
About 100 μm is preferable. Furthermore, the outer and inner surfaces of the exterior shaft 2 of the catheter may be coated with a hydrophilic resin, a fluororesin, a silicone resin, or the like with a thickness of 1 μm to several tens of μm.
By these processes, the sliding resistance of the outer and inner surfaces of the exterior shaft 2 can be reduced. In addition, antithrombotic properties can be added by coating with a resin containing heparin.

In the ultrasonic scanning of the ultrasonic catheter 1 of the present invention, the rotational movement of the motor 16 in the external unit 13 is controlled by the terminal 21 in the hand operation section 20 on the catheter side.
22 to the drive shaft 6 and the drive shaft 6
The transducer 1 provided in the housing 27 is rotated by rotating the housing 27 connected to the tip of the
This is performed by scanning the ultrasonic waves transmitted and received by the apparatus 1 in the substantially radial direction of the catheter 1. The ultrasonic image obtained here is a cross-sectional image of a blood vessel or a blood vessel. Further, by moving the entire ultrasonic catheter 1 or the drive shaft 6 in the long axis direction, a longitudinal sectional image of the blood vessel and the blood vessel can also be obtained.

FIG. 3 is a sectional view showing the structure of the transducer 11 provided in the housing 27 of the ultrasonic catheter 1 of the present invention. The vibrator 3 has electrodes 32 formed on both surfaces of a piezoelectric body 31 such as a rectangular PZT by vapor deposition, printing or the like. Here, the shape of the piezoelectric body 31 may be circular. On the back surface side of the vibrator 3, a resin material such as epoxy, urethane, acrylic resin or the like for absorbing and attenuating ultrasonic waves, or a back material 33 in which metal or inorganic powder is mixed with resin is provided. Here, as shown in FIG. 3A, the backing material 33 is provided with the unevenness 34 on the back surface side so that the thickness difference D is λ / 4 (where λ is the wavelength in the backing material at the transmission frequency). A back material that cancels reflected waves from the back surface of the material 33 by interference, or as shown in FIG. 3B, the low acoustic impedance layer 3
6 (Z = 1 × 10 ⁶ kg / m ^{2 s to} 8 × 10 ⁶ kg / m
² s) and high impedance layer 37 (Z = 20 × 10 ⁶ kg
/ M ² s or more) by alternately stacking
It may be a backing material in which the influence of reflected waves from the back surface of No. 3 is reduced.

A so-called acoustic matching layer 35 is formed on the acoustic radiation surface of the vibrator 3 so as to have a thickness of λ / 4 (λ is the wavelength in the matching layer at the transmission frequency). Although only one layer is shown in this example, two or more layers may be used.

FIGS. 4, 5 and 6 show the structure of the distal end portion of the ultrasonic catheter 1 according to the second embodiment of the present invention. 4 shows an axial sectional view of the tip portion, FIG. 5 shows a partial top view, and FIG.
Shows a sectional view taken along the line AA of FIG.

The ultrasonic catheter transducer 11 of the present invention is fixed to the housing 27 with an adhesive or the like so that the ultrasonic wave transmitting / receiving surface is approximately ± 10 ° in the direction perpendicular to the longitudinal axis direction of the ultrasonic catheter 11. It The housing 27 is bonded or brazed to the tip of the drive shaft 6 so that the bonding strength is at least 0.4 kgf or more.
Welded.

At the tip of the housing 27, a coil-shaped elastic member 19 formed in a tapered shape and having a diameter smaller toward the tip of the catheter is connected. The coil-shaped elastic member 19 is a single-layer or multi-layer coil, and is a single-strand or multi-strand coil. In the case of a multi-layer coil, the winding direction of the outermost coil is the direction tightened with respect to the rotation direction of the drive shaft. FIG.
Shows a case of a single-layer coil, which is rotated clockwise. The elastic member 19 extends so as to be inserted into the coil-shaped elastic member 41 attached to the tip of the exterior shaft by about 0.5 mm to 20 mm. The material of the coil-shaped elastic members 19 and 41 is the same as that described above.

The signal lines 7 are connected to the electrodes on both sides of the vibrator 3. Although the signal line 7 is a twisted pair in FIG. 4, it may be a coaxial line.

The drive shaft 6 is made of stainless steel (SUS3
No. 04, SUS316, etc.) is wound in two layers in two layers, and the breaking strength is 0.4 kgf or more. In addition, the drive shaft 6 is a wire or plate-shaped metal or resin coiled or braided in one or more layers, or a wire having a breaking strength of 0.4 kgf or more and a signal wire horizontally wound. May be.

At the connecting portion of the proximal side 15 of the outer shaft of the catheter with the distal side 12, the proximal side 15 is processed to be thinner toward the distal end, and the distal side 12 is formed outside thereof. In this example, since the length of the connecting portion can be relatively long, the strength of the connecting portion is high, and mechanical characteristics such as flexibility and flexibility of the exterior shaft 2 can be sequentially changed from the proximal side 15 to the distal side 12. .

FIG. 7 shows an ultrasonic catheter according to the third embodiment of the present invention. In the present invention, stainless steel (SUS304, SUS316, etc.) is attached to the tip of the housing 27,
A coil-shaped elastic member 41 made of a metal such as a NiTi alloy is connected to the coil-shaped elastic member 41, which is attached to the inside of the distal end side 12 of the exterior shaft with an adhesive 42.
It is formed to be inserted inside. Inside the coil-shaped member 41, a round wire or at least a part of a flat plate-shaped support member 43 is connected. This support member is made of stainless steel (SUS304, SUS316, etc.), NiTi.
A metal such as a system alloy is preferable and improves the mechanical strength and flexibility of the coil 41.

FIG. 8 shows a modification of the exterior shaft of the ultrasonic catheter of the present invention. In this example, the exterior shaft 15 on the hand side has a two-layer structure, and the tip side including the ultrasonic wave transmitting / receiving section has a one-layer structure. The inner layer 48 on the hand side 15 is a metal tube made of stainless steel (SUS304, SUS316, etc.), a superelastic metal tube made of NiTi alloy, etc., or a tube made of stainless steel (SUS304, SUS316, etc.) wire wound or coiled. The outer layer 49 is made of the same material as the tip side, such as a polyolefin resin or a fluorine resin. The outer layer 49 is formed by a heat shrinking method, a method of swelling with a solvent to coat the inner layer and then drying and shrinking, a dipping method, a melt extrusion molding method, or the like.

Next, an ultrasonic catheter 100 according to another embodiment of the present invention will be described with reference to the drawings.

The ultrasonic catheter 100 of this embodiment is
As shown in FIGS. 10 and 12, the exterior shaft assembly 102 inserted into the body cavity, the drive shaft assembly 106 inserted into the exterior shaft 102, and the exterior shaft assembly 102 fixed to the proximal end thereof. And a connector 120.

As shown in FIG. 11, the exterior shaft assembly 102 has a tip 112 and a body 115.
The tip portion 112 of the exterior shaft assembly 102 includes a tip central portion 112b provided with a coil-shaped elastic member 141, and a portion 112 not provided with the elastic member 141 before and after the central portion 112b.
a, 112c (ultrasonic wave transmitting / receiving portion). The transducer 11 is located inside the 112c portion.

As shown in FIG. 12, the tip end opening of the exterior shaft assembly 102 is provided with a communication port in the center for communicating the outside and the inside of the shaft assembly 102, and the tip end side is formed in a hemispherical shape. 117 is fixed. The coil-shaped elastic member 14 extends from the position slightly closer to the base end side of the shaft assembly 102 to the base end side by a predetermined distance.
1 is provided. The coil-shaped elastic member 141 is fixed by being sandwiched between the outer layer 102a and the inner layer 102c. Thus, by not exposing the outer surface of the coil-shaped elastic member 141, the slidability of the catheter 100 within the guiding catheter is improved.

By not providing the coiled elastic member 141 up to the tip, the distal end of the catheter becomes flexible. As a result, when the distal end of the catheter comes into contact with the inner wall of the blood vessel, the distal end of the catheter is less likely to damage the inner wall of the blood vessel.

Further, the distal end member 137 may not have a communication port like the catheter 150 shown in FIG. In this case, the inside of the catheter may be filled with a liquid 138 such as physiological saline that is harmless to the living body. This eliminates the need for priming work during use.

The length of the coil-shaped elastic member varies depending on the length of the entire catheter, but is preferably about 5 to 50 mm, more preferably 10 to 30 mm. Further, the length of the most distal end portion 112a without the elastic member 141 is 1
It may be about 10 mm, preferably 1 to 5 mm. The elastic member 141 may extend to the tip of the shaft 102. The coil-shaped elastic member 141 is preferably made of metal, and particularly Pt, Ir, A
A high X-ray contrast material (high X-ray contrast metal) such as a metal such as u or an alloy material thereof is suitable.

The main body 115 of the drive shaft assembly 102 has an intermediate layer 102b made of a hard material. As shown in FIG. 12, the outer shaft assembly 102 includes an outer layer 102 extending from the base end to the tip of the outer shaft.
It is a two-layer tube body having a and an inner layer 102c.

Outer layer 102a of exterior shaft assembly 102
As a material for forming the inner layer 102c, a resin having excellent ultrasonic wave permeability is suitable. For example, a polyolefin resin, a polyurethane resin, a resin, a fluorine resin, or the like can be used. Particularly, from the viewpoint of ease of molding, polyethylene is used, specifically, low density polyethylene is used as the outer layer and high density as the inner layer. It is preferable to use density polyethylene. The wall thickness of the shaft assembly at the portion forming the ultrasonic wave transmitting / receiving portion 112c is preferably about 10 to 100 μm.

The main body 115 includes an outer layer 102a and an inner layer 1
The reinforcing layer 102b is provided in the middle of 02c. As the reinforcing layer, a tube made of hard resin, elastic metal, super elastic metal or the like is used.

Examples of elastic metals include simple metals such as iron, tungsten, and copper, and alloys containing any of these metals (for example, SUS304, SUS316, S).
Austenitic stainless steel such as US321, maraging stainless steel, Cu-Zn alloy, Cu-Sn alloy) and the like can be used. Austenitic stainless steel is preferable.

The superelastic metal is generally called a shape memory alloy, and has superelasticity at least at a living body temperature (around 37 ° C.). The term "superelasticity" as used herein means that even if a normal metal is deformed (bent, stretched, compressed) to a region where it is plastically deformed at a use temperature, the metal substantially recovers its original shape. As the superelastic metal, a Ti-Ni alloy containing substantially 49 to 58 atomic% Ni (the balance Ti), and substantially 38.
Cu-Zn alloy of 5 to 41.5 wt% Zn (balance Cu), Cu-Zn-X alloy in which a part of this Cu-Zn alloy is replaced with 1 to 10 wt% X (X = Be, Si, Sn , A
1, Ga), substantially 36 to 38 atomic% Al (balance N
The Ni-Al alloy of i) is suitable. Particularly preferred are the above-mentioned Ti-Ni alloys. Further, Ti-in which a part of the Ti-Ni alloy is replaced with 0.01 to 2.0 atomic% X-
Ni-X alloy (X = Co, Fe, Mn, Cr, V, A
1, Nb, Pd, B, etc.), the mechanical characteristics can be appropriately changed.

A spiral slit extending from the tip to the rear side is provided at the tip of the tube (for example, elastic metal tube) forming the intermediate layer (reinforcing layer) 102b. As a result, the tip of the elastic metal tube is a flexible deformable portion as compared with other portions, and the tip of the elastic metal tube is
The side wall is deformable inside the super elastic metal tube. It is preferable that the slit has a width that gradually decreases from the front end of the elastic metal tube toward the rear end side, in other words, the width gradually increases toward the front end side. For this reason, the slit width at the tip of the elastic metal tube is the maximum, and the elastic metal tube is more easily deformed toward the tip. It is preferable that about 2 to 8 slits are provided at substantially equal intervals. The width of the tip of the slit (width of the maximum portion) is preferably about 0.05 to 0.5 mm. Also, the width of the slit is about 1 / outer diameter of the elastic metal tube.
6 to 3/2 is preferable, and about 1/3 to 1/1 is particularly preferable.

The pitch of the spiral slit may be short on the tip end side of the slit and long on the base end side of the slit. If the pitch of the slit changes, 0.3 mm ~ at the tip.
About 3.0 mm, about 5 to 10 mm is preferable at the base end portion, and particularly, in the middle portion between the tip end portion and the base end portion, there is an intermediate pitch between the two, or the pitch gradually changes. It is preferable. Further, the slits 19 preferably have the above-mentioned changing pitch and changing width.

The slits and the pores described later can be formed in the metal tube by laser processing (for example, YAG laser), electric discharge processing, chemical etching, cutting processing and the like, or by using them together.

The outer surface or both the outer surface and the inner surface of the exterior shaft assembly may be coated with a hydrophilic resin, a fluororesin, a silicone resin or the like in a thickness of 1 μm to several tens of μm. These treatments can reduce the sliding resistance on the surface of the exterior shaft. Further, the outer surface of the exterior shaft may be coated or fixed with an antithrombotic substance. The antithrombotic substance coating is
For example, it is performed by coating the outer surface of the shaft with a resin containing heparin.

The outer surface of the outer shaft 102 preferably has a wettability or hydrophilicity added by surface treatment. By making the surface of the outer layer shaft highly lubricious or wettable, the contact resistance with the inner wall of the body cavity at the time of insertion becomes small, and insertion into the target site becomes easy. As a method of improving lubricity or wettability, a method of introducing a functional group into the resin film forming the outer layer 102a and then coating or fixing a polymer material having high lubricity or wettability is used. Examples of the polymer material include poly (2-hydroxyethyl methacrylate), polyhydroxyethyl acrylate,
Hydrophilic polymers such as hydroxypropyl cellulose, methyl vinyl ether maleic anhydride copolymer, polyethylene glycol, polyacrylamide, and polyvinylpyrrolidone are used.

The drive shaft assembly 106, as shown in FIGS. 13, 14 and 15, is a shaft main body 106a.
A housing 127 for housing a transducer fixed to the tip of the shaft body 106a, and a housing 12
A rod-shaped elastic member 119 fixed to the tip of the No. 7 is provided.

As the elastic member 119, a rod-shaped body made of elastic metal such as stainless steel, superelastic metal, resin such as polyacetal, or the like is used. In particular, super elastic metal or elastic metal is preferable. As a super elastic metal,
The above can be used. Since the rod-shaped body has high flexibility, a coil-shaped rod-shaped body is used in this embodiment.

Elastic member 11 of drive shaft assembly 106
9 is preferably about 2 to 30 mm, and 3
-20 mm is more preferable. Further, as shown in FIG. 12, the distal end portion of the elastic member 119 has a coil-shaped elastic member 141.
Has penetrated into the proximal end of the. In other words, the tip of the second elastic member 119 is located inside the first elastic member 141. The elastic member 141 and the elastic member 119 reinforce each other. As a result, changes in the physical properties of the shaft assembly before and after the proximal end of the coil-shaped elastic member 141 are buffered. Therefore, the catheter is prevented from kinking near the proximal end of the coil-shaped elastic member 141.
Similarly, changes in the physical properties of the catheter 1 before and after the tip of the elastic member 119 are buffered by the coil-shaped elastic member 141. Therefore, the catheter is prevented from kinking near the tip of the elastic member 119. It is preferable that the elastic member 119 penetrates the portion where the coil-shaped elastic member 141 is provided by about 0.5 mm to 20 mm. The elastic member 119 is connected to the tip of the housing 27 by adhesion, brazing, welding or the like.

The drive shaft body 106a has two layers of flat plates made of stainless steel (SUS304, SUS316, etc.).
It is formed by a thread. The drive shaft preferably has a breaking strength of 0.4 kgf or more. The drive shaft main body 106 may be a wire or plate-shaped metal or resin coiled or braided in one or more layers. Also, the drive shaft is
A signal wire, which will be described later, may be wound horizontally on a wire having a breaking strength of 0.4 kgf or more.

Specifically, the drive shaft body 106 is
It is formed by a coil. As the material for forming the drive shaft, the above-mentioned superelastic alloy, precipitation hardening type stainless steel (PH stainless steel, particularly preferably semi-austenite type), metallic material such as maraging stainless steel, and other stainless steel are preferably used. The number of layers of the coil body is not limited to one. In order to improve the torque transmissibility, it is preferable to have a multilayer structure of two or more layers. In this case, the winding directions of the layers are preferably opposite to each other. By doing so, the transmissibility of the pushing pressure applied at the proximal end portion of the catheter is high, and the transmissibility of the torque is also high.

As shown in FIGS. 14 and 15, the housing 127 for housing the transducer is a cylindrical body having an outer diameter substantially equal to that of the drive shaft 106. Housing 1
27 has a fixed portion 118 of the transducer formed by cutting the side surface near the center in the axial direction of a predetermined length and cutting out about half of the circular arc. In this embodiment, the tip side of the fixed portion 118 is slanted. Housing 12
As the forming material of 7, metal, resin, ceramics, or the like is used. The tip of the drive shaft main body 106a has a small diameter, and this tip is inserted and fixed to the base end of the housing 127. Also, the housing 127
In the case where is formed of a conductive material, it is preferable to interpose an insulating material on the contact surface between the tip of the drive shaft main body and the housing 127.

The housing 127 is fixed so that the outer surface of the ultrasonic transmitting / receiving surface of the transducer 11 is exposed in the housing portion. As the transducer 11,
The type shown and described in FIG. 3B is used. The transducer 11 is housed in the housing 127 so that the acoustic matching layer 35 is on the outer side and the back material 33 is on the inner surface side of the housing 127, and is fixed by an adhesive. In the drive shaft main body 106a, signal lines 107a and 107b formed by two lead wires to which the electrodes 32a and 32b of the transducer 11 are connected are housed. The connector 120 is the base end side (hand side) of the signal line.
(Not shown). The hand operation unit (connector) 120 has a structure similar to that shown in FIG.

Ultrasonic scanning in the ultrasonic catheter of the present invention will be described. The ultrasonic scanning will be described with reference to FIG. 1, but it is common to all the above-described embodiments.

In ultrasonic scanning of the ultrasonic catheter 1, the motor 16 in the external unit 13 is rotated while transmitting and receiving ultrasonic waves by the transducer, and the rotational movement is performed by the terminal 21 in the connector 20 of the catheter.
It is transmitted to the drive shaft 6 via 22 to rotate the housing 27 connected to the tip of the drive shaft 6.
Thereby, the ultrasonic waves transmitted and received by the transducer 11 are scanned in the radial direction of the catheter 1, and an ultrasonic image can be obtained. The ultrasonic image obtained here is a cross-sectional image of a blood vessel or a blood vessel. Further, by moving the ultrasonic catheter in the axial direction of the catheter, it is possible to obtain a longitudinal sectional image of blood vessels and vessels. Further, by moving the drive shaft 6 in the axial direction of the catheter to configure the catheter and the external unit, it is possible to obtain a longitudinal sectional image of a blood vessel and a vascular vessel.

Next, a procedure for operating the ultrasonic catheter of the present invention in a blood vessel will be described.

In the ultrasonic catheter, an introducer or the like is inserted into the blood vessel from outside the body, and a guiding catheter having a guide wire inserted therein is inserted into the introducer, as in the case of a normal blood vessel catheter procedure. After the vicinity of the tip of the guide wire reaches the target site to be examined or treated, the ultrasonic catheter of the present invention is inserted into the guiding catheter. Then, as described above, a cross-sectional image of the blood vessel is obtained by performing the ultrasonic operation. At this time, the guide wire may be left in the guiding catheter. Further, the guide wire may be removed from the guiding catheter. Further, the ultrasonic catheter of the present invention is not limited to the one using the guiding catheter, and the ultrasonic catheter of the present invention may be inserted into the guide wire lumen of a therapeutic catheter such as a balloon catheter. In such a case, the outer diameter of the ultrasonic catheter is preferably 0.25 mm to 0.97 mm, more preferably 0.35 mm to 0.46 mm.

[0097]

In the ultrasonic catheter of the present invention, the distal end portion of the second elastic member is inserted into the coil-shaped first elastic member, so that the space between the housing and the coil at the catheter distal end portion is increased. Can be reinforced, and kink resistance and flexibility can be improved. Therefore, the running performance of the present catheter in a blood vessel or a vascular vessel in the body cavity is improved, and the operability of the ultrasonic catheter is improved.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing a state in which an external unit is attached to the ultrasonic catheter of the present invention.

FIG. 2 is a partial cross-sectional view of a hand operation portion (connector) portion and an external unit of the ultrasonic catheter of the present invention.

FIG. 3 is a cross-sectional view showing the structure of an example of a transducer used in the ultrasonic catheter of the present invention.

FIG. 4 is a cross-sectional view of a distal end portion of an ultrasonic catheter according to another embodiment of the present invention.

5 is a plan view near the transducer of the ultrasonic catheter shown in FIG. 4. FIG.

6 is a cross-sectional view taken along the line AA of FIG.

FIG. 7 is a cross-sectional view of a distal end portion of an ultrasonic catheter according to another embodiment of the present invention.

FIG. 8 is a partial cross-sectional view of an example of an exterior shaft used in the ultrasonic catheter of the present invention.

FIG. 9 is a partially enlarged cross-sectional view of a hand operation portion (connector) portion and an external unit of the ultrasonic catheter of the present invention.

FIG. 10 is an external view of an ultrasonic catheter according to another embodiment of the present invention.

11 is an enlarged view of the vicinity of the tip of the ultrasonic catheter shown in FIG.

12 is an enlarged cross-sectional view of the distal end portion of the catheter shown in FIG.

13 is an enlarged view of the vicinity of the tip of the drive shaft assembly used in the catheter shown in FIG.

14 is a plan view near the transducer of the drive shaft assembly shown in FIG. 13. FIG.

15 is a cross-sectional view of the drive shaft assembly shown in FIG.

FIG. 16 is an enlarged view of the vicinity of the tip of an ultrasonic catheter according to another embodiment of the present invention.

FIG. 17 is a partial cross-sectional view of a conventional ultrasonic catheter with an external unit attached.

FIG. 18 is a cross-sectional view of a distal end portion of another conventional ultrasonic catheter.

[Explanation of symbols]

 1 Ultrasonic Catheter 2 Exterior Shaft 6 Drive Shaft 10 Ultrasonic Catheter Device 11 Transducer 13 External Unit 20 Hand Control Unit (Connector) 27 Housing 100 Ultrasonic Catheter

Claims (18)

[Claims] 1. An exterior shaft which is inserted into a body cavity, a drive shaft which is inserted into the exterior shaft, and which transmits a mechanical driving force from a proximal end side to a distal end side, and an ultrasonic transducer. So that it is located inside the tip of the shaft,
An ultrasonic catheter having a housing fixed to the drive shaft, wherein the drive shaft is rotatable by an external drive source, wherein the exterior shaft includes a coil-shaped first elastic member at a distal end portion, The ultrasonic catheter, wherein the housing has a second elastic member at a distal end portion thereof and extends toward a distal end side of the catheter, and a distal end of the second elastic member is located inside the first elastic member. . 2. The ultrasonic catheter according to claim 1, wherein the length of the portion of the second elastic member that has penetrated into the first elastic member is 0.5 mm to 20 mm. 3. The ultrasonic catheter according to claim 1, wherein the second elastic member is a coil-shaped elastic member. 4. The at least part of the second elastic member is made of superelastic metal.
The ultrasonic catheter according to any one of 1. 5. The ultrasonic catheter according to claim 1, wherein the exterior shaft includes a tube that forms a reinforcing layer, and a spiral slit is provided at a tip portion of the tube. . 6. The ultrasonic catheter according to claim 1, wherein the first elastic member has an opening that connects the inside and the outside of the catheter. 7. The ultrasonic catheter according to claim 1, wherein the first elastic member is made of a high X-ray contrast material. 8. The ultrasonic catheter according to claim 1, wherein the second elastic member is formed in a tapered shape whose diameter decreases toward the distal end side. 9. The ultrasonic catheter according to claim 1, wherein the first elastic member is formed in a taper shape whose diameter decreases toward the distal end side. 10. The ultrasonic catheter according to claim 1, wherein the first elastic member includes a support member inside. 11. The ultrasonic catheter according to claim 1, wherein the ultrasonic transducer is provided in a transducer fixed to the housing. 12. An exterior shaft having an outer layer and an inner layer, a drive shaft inserted into the exterior shaft, and an ultrasonic transducer, wherein the drive shaft is located inside the tip side of the exterior shaft. A fixed housing, a first elastic member located at the tip of the outer shaft and inserted between the outer layer and the inner layer, and fixed to the tip of the housing, on the tip side of the catheter. An ultrasonic catheter, comprising: a second elastic member that extends; and a tip of the second elastic member located inside the first elastic member. 13. The ultrasonic catheter according to claim 12, wherein the exterior shaft has a tip member fixed to the tip thereof and having an opening. 14. The outer shaft has a closed tip member fixed to the tip thereof, and the catheter has a closed and liquid-filled internal space. Ultrasonic catheter. 15. The main body of the exterior shaft has a reinforcing layer located between the exterior and the inner layer.
The ultrasonic catheter according to 2. 16. The ultrasonic catheter according to claim 15, wherein the first elastic member and the reinforcing layer are not present on the exterior shaft of the portion where the housing is located. 17. The ultrasonic catheter according to claim 15, wherein the tip portion of the reinforcing layer has a spiral slit. 18. The ultrasonic transducer is an ultrasonic transducer portion included in an ultrasonic transducer.
The ultrasonic catheter according to 1.