JPH08206114A - Ultrasonic catheter - Google Patents

Abstract

PURPOSE: To provide an ultrasonic catheter which can be inserted into a body cavity such as a blood vessel and a vessel and exhibits high bending properties, durability, torque transmitting properties and pushability and also exhibits excellent running properties in the blood vessel. CONSTITUTION: An ultrasonic catheter 1 has an ultrasonic oscillator 2, a driving shaft 3 which is provided on the base end side from the ultrasonic oscillator 2 and transmits a driving force from the outside driving source 31 to the ultrasonic oscillator 2 to rotate or reciprocate the ultrasonic oscillator 2 and a hollow sheathed shaft 4 covering the ultrasonic oscillator 2 and a driving shaft 3. In addition, the sheathed shaft 4 is formed of a polyimide resin with a outer diameter of 1mm or smaller and a thickness of 50μm or less and additionally, the min. interval between the theathed shaft 4 and the driving shaft 3 is made to be 100μm or below.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic catheter used by inserting it into a body cavity such as a blood vessel or a blood vessel.

[0002]

2. Description of the Related Art Conventionally, an ultrasonic catheter is known which is inserted into a coronary artery of a heart, other small blood vessels, or a blood vessel such as a bile duct to display a sectional image of a lumen and measure blood flow. .
Since all ultrasonic catheters currently used have an outer diameter of 1 mm or more, when using a catheter for treatment such as a balloon catheter for vasodilation, a catheter for laser irradiation, or an atherectomy catheter, the treatment catheter is used. Is used in exchange. In addition, the ultrasonic catheters currently used are often of the over-the-wire type and the monorail wire type, which are used by inserting a guide wire into the ultrasonic catheter because the blood vessel running ability by themselves is insufficient.

Accordingly, there is a demand for an ultrasonic catheter which can be used simultaneously with a therapeutic catheter and a guide wire type ultrasonic catheter which can be inserted further into the periphery and has excellent blood vessel selectivity. To meet this demand, at least the outer diameter of the ultrasonic catheter is required to be 1 mm or less, preferably 0.4 mm or less.

There are two types of ultrasonic catheters, a mechanical scanning type and an electronic scanning type. The former structure has an ultrasonic transducer at the tip of the catheter that is inserted into the body cavity,
The catheter has a signal transmission body connected to the oscillator and an external electric circuit, and has a mechanism for mechanically rotating or reciprocating the oscillator or the ultrasonic reflection plate. Known as this mechanism are a method of directly driving by a small motor built in the tip of the catheter and a remote driving method of transmitting a driving force from a driving source outside the catheter by a driving shaft built in the catheter. The latter has a plurality of ultrasonic transducers at the tip of the catheter to be inserted into the body cavity, a switching circuit, and a signal transmitter for transmitting a signal to an external circuit.

From the viewpoint of the image quality of an ultrasonic image, it is said that the mechanical scanning type is superior because a simple ultrasonic beam can be obtained, and in order to realize the reduction in diameter of an ultrasonic catheter. Has to be mechanical. Also, with the method of incorporating a motor in the catheter, it is extremely difficult to manufacture a motor that fits when the outer diameter of the catheter is 1 mm or less, particularly 0.4 mm or less, and the cost is also very expensive. . Therefore, in order to effectively reduce the diameter, it is considered that a mechanical scanning type and a remote drive type ultrasonic catheter is most suitable.

In any of the above ultrasonic catheters, the outer shaft is reinforced by a so-called catheter material such as a nylon-based, olefin-based, polyester-based, polyurethane-based resin single-layer shaft, or a metal blade or coil. Multi-layered shafts have been used. In the conventional mechanical scanning type remote drive ultrasonic catheter with an outer diameter of 1 mm or more, the wall thickness of the outer shaft can be set to 200 μm or more. Therefore, by using the above materials, sufficient strength and durability can be obtained. An outer shaft can be formed, and an ultrasonic catheter with good performance can be obtained.

[0007]

However, in order to obtain an ultrasonic catheter having an outer diameter of 1 mm or less, preferably 0.4 mm or less, the rotation or reciprocating motion of the drive shaft and the ultrasonic transducer should not be disturbed. Since the outer diameter of the drive shaft and the radial width of the ultrasonic transducer and the distance between the drive shaft and the ultrasonic transducer and the outer shaft are desired to be sufficiently large, the outer shaft has a small wall thickness and flexibility,
It is required to have excellent kink resistance, torque transmission, and pushability (pushability), and also to have the friction resistance of the inner surface as small as possible. However, in order to meet this requirement, the resin single-layer shaft and the multi-layer shaft that have been conventionally used cannot have a sufficient wall thickness, and the frictional resistance of the inner surface thereof is relatively large, and good characteristics can be obtained. Absent.

Therefore, the present invention is an ultrasonic catheter having an outer diameter of 1 mm or less, preferably 0.4 mm or less, and also has flexibility, kink resistance, torque transmission, and pushability. It is an object of the present invention to provide an ultrasonic catheter that has high performance and is excellent in operability and that can obtain a stable ultrasonic image and that has excellent performance. Another object of the present invention is to provide an ultrasonic catheter that can reduce the frictional resistance on the inner surface of the exterior shaft. Another object of the present invention is to provide an ultrafine ultrasonic catheter which can be suitably used by inserting it into a therapeutic catheter such as a vasodilator balloon catheter, a laser irradiation catheter, an atherectomy catheter or the like.

[0009]

[Means for Solving the Problems] The above-mentioned object is as follows (1)
It is achieved by the present invention according to (10) to (10).

(1) An ultrasonic catheter used by being inserted into a body cavity, which comprises an ultrasonic vibrator and a driving force provided from a driving source outside the body, which is provided on the proximal side of the ultrasonic vibrator. A drive shaft that transmits to the ultrasonic oscillator to rotate or reciprocate the ultrasonic oscillator; and a hollow exterior shaft that encloses the ultrasonic oscillator and the drive shaft,
The outer shaft is made of polyimide resin and has an outer diameter of 1 mm.
Hereinafter, an ultrasonic catheter characterized in that the thickness is formed to 50 μm or less, and the minimum distance between the exterior shaft and the drive shaft is 100 μm or less.

(2) An ultrasonic catheter used by being inserted into a body cavity, comprising: an ultrasonic transducer; and an ultrasonic reflector for reflecting the ultrasonic waves transmitted from the ultrasonic transducer into the body cavity. A drive shaft which is provided on the proximal side of the ultrasonic reflector and transmits a driving force from a drive source outside the body to the ultrasonic reflector to rotate or reciprocate the ultrasonic reflector, and the ultrasonic vibrator. A hollow exterior shaft that encloses the ultrasonic reflector and the drive shaft, the exterior shaft is made of polyimide resin and has an outer diameter of 1 mm or less and a wall thickness of 50.
An ultrasonic catheter characterized in that it is formed to have a thickness of not more than 100 μm, and the minimum distance between the outer shaft and the drive shaft is not more than 100 μm.

(3) On the outer side of the drive shaft, there is integrally provided a signal transmission body for transmitting a signal between the ultrasonic transducer and a transmission / reception circuit outside the body. The ultrasonic catheter according to the above (1) or (2), characterized in that the distance between the outer casing and the exterior shaft is the minimum distance.

(4) The ultrasonic catheter according to any one of (1) to (3) above, wherein the polyimide resin contains 5 to 30% of a fluorine resin.

(5) The ultrasonic catheter as described in any one of (1) to (4) above, wherein a spiral groove is formed from the tip of the exterior shaft to a predetermined length.

(6) The ultrasonic catheter according to any one of the above (1) to (5), characterized in that the pitch of the spiral groove is reduced toward the distal end.

(7) The ultrasonic catheter according to any one of the above (1) to (6), characterized in that a guide member for the ultrasonic catheter is provided at the tip of the outer shaft.

(8) The ultrasonic catheter according to any one of the above (1) to (6), wherein the guide member is a coil spring fixed to the tip of the exterior shaft.

(9) The ultrasonic catheter according to any one of the above (1) to (6), wherein the guide member is made of a super elastic metal wire fixed to the tip of the outer shaft.

(10) The ultrasonic catheter according to any one of the above (1) to (9), wherein an X-ray contrast-enhancing member is provided on the distal end side of the ultrasonic catheter.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on the embodiments shown in the accompanying drawings.

FIG. 1 is a partial sectional side view showing an embodiment of an ultrasonic catheter of the present invention, and FIG. 2 is an enlarged vertical sectional view showing an ultrasonic transducer and a backing material of the embodiment shown in FIG.
FIG. 3 is an enlarged vertical sectional view showing a modified example of the back material, and FIG.
FIG. 4 is an end view taken along line IV-IV in FIG. 1. In addition, in FIG.
The intermediate part of the ultrasonic catheter of the present invention is omitted. In addition, the left side in FIGS. 1, 3 and 4 is referred to as a “tip” and the right side is referred to as a “base end”.

The ultrasonic catheter 1 of the present invention shown in FIG.
Is an ultrasonic catheter that is used by being inserted into a body cavity, and is provided with an ultrasonic transducer 2 and a proximal end side of the ultrasonic transducer 2, and ultrasonically vibrates a driving force from a driving source 21 outside the body. It has a drive shaft 3 that is transmitted to the child 2 to rotate or reciprocate the ultrasonic oscillator 2, and a hollow exterior shaft 4 that encloses the ultrasonic oscillator 2 and the drive shaft 3. The resin is formed to have an outer diameter of 1 mm or less and a wall thickness of 50 μm or less, and further, the minimum distance between the exterior shaft 4 and the drive shaft 3 is 100 μm or less.

The ultrasonic transducer 2 is arranged at the tip of the ultrasonic catheter 1, and as shown in FIG. 2, a ceramic piezoelectric material such as PZT (lead zirconate titanate) or PbTiO ₃ (lead titanate). Or both surfaces of a piezoelectric body 21 composed of a polymer piezoelectric body such as PVDF (polyvinylidene fluoride), a composite piezoelectric body of the above ceramic and a polymer, or the like.
The electrode 22 is formed by vapor deposition, printing or the like. As the ultrasonic transducer 2, the radial width t of the ultrasonic catheter 1 is about 0.9 mm or less, preferably 0.15
It is about 0.25 mm, and the specific acoustic impedance is 4
It is about × 10 ⁶ to 4 × 10 ⁷ kg / m ² · s.

On the back surface of the ultrasonic transducer 2, a backing material 5 for absorbing and attenuating unnecessary ultrasonic waves emitted to the back surface side.
Is preferably provided. The backing material 5 is formed of a material having a high ultrasonic attenuation rate, such as a resin material such as an epoxy resin, a polyurethane resin, an acrylic resin, or a rubber material such as a silicone rubber. For example, an adhesive such as an epoxy adhesive is used. The agent is provided so as to adhere to the ultrasonic transducer 2 so as not to be substantially displaced. In addition, for the purpose of more effectively absorbing and attenuating ultrasonic waves by the back material 5, scatterers (for example, tungsten) having different specific impedances may be contained in the above materials.

The backing material 5 shown in FIG. 2 has irregularities 51 on the back surface side thereof, the thickness difference D of which is λ / 4 (λ is the wavelength in the backing material at the transmission frequency). By the unevenness 51, the reflected wave from the back surface of the backing material 5 can be canceled by interference, and the influence of the reflected wave from the back surface can be reduced.

The backing material 5 shown in FIG. 2 has a thickness of about 0.04 to 0.2 mm, and the concavities and convexities 51 have a dimension D of about 7 to 50 μm and a convex width of 30. ~
It is about 200 μm, and the width of the recess is about 30 to 200 μm.

The backing material may be as shown in FIG. The backing material 4 shown in FIG. 3 has a low acoustic impedance layer 52 (specific acoustic impedance Z is 8 × 10
⁶ kg / m ² · s or less) and the high impedance layer 53 (the specific acoustic impedance Z is 20 × 6 kg / m ² · s or more) are alternately laminated. With such a configuration, the reflected wave from the back surface of the backing material 5 can be canceled by interference, and the influence of the reflected wave from the back surface can be reduced. The backing material 5 shown in FIG. 3 has a thickness of 0.0
It is about 4 to 0.2 mm.

The drive shaft 3 shown in FIG. 1 is composed of a hollow coil formed by spirally winding a wire rod. As the wire rod that constitutes the drive shaft 3, as shown in FIG. 1, in addition to a flat plate having a horizontally long rectangular cross section, a rod having a substantially horizontal cross section such as a circular shape or an elliptical shape can be used. Can be used. Of these, a flat coil made of a flat wire as shown in the drawing is preferable because the coil can be made thinner and the outer diameter of the drive shaft 3 can be reduced. The illustrated drive shaft 3 is a single-layer coil, but it may be a coil having two or more layers.

The constituent material of the drive shaft 3 (that is, the constituent material of the wire) is, for example, stainless steel, Ni-Ti having substantially 49 to 58 atomic% Ni (the balance Ni).
System alloy, part of this Ni-Ti system alloy is 0.01-2.
Ni-Ti-X based alloy substituted with 0% X (X is Co,
Fe, Mn, Cr, V, Al, Nb, Pb, B, etc.), substantially 38.5-41.5% by weight Zn (balance Cu) C
u-Zn-based alloy, Cu-Zn-X-based alloy in which a part of this alloy is replaced with 1 to 10 wt% X (X is Be, Si, S
n, Al), substantially 36 to 38 atomic% Al (balance N
i) Superelastic alloy such as Ni-Al alloy, precipitation hardening stainless steel (PH stainless steel, particularly preferably semi-austenitic), stainless steel such as maraging stainless steel, metal material such as high-strength steel, etc. are used. To be

Of these, superelastic alloys such as Ni-Ti alloys are particularly preferable. The superelastic alloy referred to here is generally called a shape memory alloy, and is at least at a living body temperature (37 ° C).
In the vicinity), it exhibits superelasticity (a property in which an ordinary metal returns to its original shape even after being deformed to a region where permanent deformation occurs).

As for the dimensions of the drive shaft 3, when the plate coil shown in the drawing is used, the outer diameter is 0.9 mm or less, preferably about 0.2 to 0.3 mm, and the thickness is 0.02 to 0.02.
The coil width is about 0.2 mm, preferably about 0.05 to 0.15 mm, and the coil width is about 0.05 to 0.3 mm, preferably about 0.07 to 0.2 mm.

A connecting member 7 is attached to the tip of the drive shaft 3. As shown in FIG. 4, the connecting member 7 has a cylindrical shape having a slit 7a on its side surface. The base end of the connecting member 7 and its vicinity are inserted into the drive shaft 3 and fixed to the inner surface of the drive shaft 3 with an adhesive or the like, and the tip end thereof is attached to the base end of the backing material 5 with an adhesive or the like. It is fixed. As a result, the ultrasonic vibrator 2 is integrally connected to the drive shaft 3 together with the backing material 5, and rotates or reciprocates as the drive shaft 3 rotates or reciprocates. The ultrasonic vibrator 2 may be directly connected to the drive shaft 3 without a connecting member as illustrated.

As shown in FIGS. 2 and 3, the ultrasonic transducer 2 is attached to each of the two electrodes 22 of the ultrasonic transducer 2.
And a transmission / reception circuit 32, which will be described later, are electrically connected to a signal line 6 which is a signal transmitter for transmitting a signal. Each of these signal lines 6 is, as shown in FIG.
It is composed of a conductor 6a and an insulator 6b which covers the conductor 6a and electrically insulates it. One conductor 6a
Has a tip connected to one of the electrodes 22 and the other conductor 6a.
Is connected to the other electrode 22. The signal line 6 enters the inner cavity of the drive shaft 3 through the slit 7 a of the connecting member 7, and extends through the inner cavity to the inside of the connector 10 described later.

The exterior shaft 4 is made of a polyimide resin and is provided so as to enclose the ultrasonic vibrator 2, the drive shaft 3, the backing material 5 and the like. The outer shaft 4 has an outer diameter of 1 mm or less, preferably 0.4 mm or less, and a wall thickness of 50 μm or less, preferably about 20 to 40 μm. The minimum distance 1 is 100 μm or less, preferably about 10 to 50 μm.

The exterior shaft 4 thus constructed is
It has a tensile strength of 0.5 Kgf or more and a high bendability that does not cause a kink even when bent with an outside diameter of 10 mm or less.
Sliding resistance is small (dynamic friction resistance is 0.1 or less) when the drive shaft 3 rotates or reciprocates, or when it is inserted into another catheter such as a treatment catheter for use. Therefore, it has excellent pushability and trackability,
It is possible to provide an ultrasonic catheter having an outer diameter of 1 mm or less, which can obtain a stable ultrasonic image and has excellent operability. Here, the bending outer diameter refers to an outer diameter that, when deformed by an external force up to a predetermined bending outer diameter, does not substantially cause a kink, and after removing the external force, returns to an almost original shape.

As the polyimide resin constituting the exterior shaft 4, for example, a homopolymer of polyimide such as polyimide resin, polyamideimide resin, polyesterimide resin, polyetherimide resin and the like are the main constituent components, and other The thing which copolymerized the polymer component of. In addition, such a polyimide-based resin may be mixed with, for example, an alloying agent, a compatibilizing agent, a stabilizer, various pigments, or the like, within a range that does not impair the characteristics thereof.
It does not matter if other resin materials are blended.

In particular, for example, an ethylene-tetrafluoroethylene copolymer (ETF) is added to the above polyimide resin.
E), polychlorotrifluoroethylene, polyvinyl fluoride, vinylidene fluoride, hexafluoropropylene-
It is preferable that a fluorine-based resin such as tetrafluoroethylene copolymer or chlorotrifluoroethylene-vinylidene fluoride copolymer be mixed and used as a constituent material of the exterior shaft 4. By containing the fluorine-based resin, the sliding resistance of the exterior shaft 4 can be further reduced.

When the fluorine resin is mixed in this way,
The mixing amount of the fluorine-based resin is 5 to 5 of the above polyimide-based resin.
It is preferably 30% by weight, more preferably 5 to 10% by weight. With such a ratio, the sliding resistance of the exterior shaft 4 can be effectively reduced without impairing the characteristics of the polyimide resin (specifically, the dynamic friction resistance is 10 to 40%).
Can be reduced).

The inner surface of the outer shaft 4 is made of a low friction resin such as silicone or polyethylene terephthalate (Teflon), or poly (2-hydroxyethyl methacrylate), polyhydroxyethyl acrylate, hydroxypropyl cellulose, methyl vinyl ether maleic anhydride. It is also possible to reduce the sliding resistance of the inner surface of the exterior shaft 4 by thinly coating (about several μm) with a hydrophilic resin such as an acid copolymer.

The outer shaft 4 can be formed, for example, by molding the above-mentioned polyimide resin by an electric wire coating method by melt extrusion, a dipping method, or the like.

The exterior shaft 4 formed of such a polyimide resin has a considerable strength (specifically, a tensile strength of 1 kg) even if it is thin with a thickness of about 50 μm.
And the sliding resistance can be reduced (dynamic friction resistance of 0.1 or less). Therefore, the outer diameter is 1 mm or less, the wall thickness is 50 μm or less, and the distance from the drive shaft 3 is 100 μm.
It is preferably used as an outer shaft of an ultrasonic catheter having a small diameter of m or less. The thickness of the outer shaft 4 is 50
It is not more than μm, preferably about 20 to 40 μm. If the thickness is within this range, the radial widths of the drive shaft 3 and the ultrasonic transducer 2 can be sufficiently secured, and an ultrasonic catheter having an outer diameter of 1 mm or less can be suitably manufactured.

The exterior shaft 4 and the drive shaft 3
The minimum distance l between and is 100 μm or less, preferably 10 to
It is about 50 μm. If this distance l exceeds 100 μm, the clearance between the drive shaft 3 and the exterior shaft 4 is too large, and when the ultrasonic catheter 1 bends along the shape of the body cavity when it is inserted into the body cavity, the drive is performed. It is easy for the shaft 3 to largely shift in the radial direction within the exterior shaft 4,
The driving force from the mechanical driving source 31 described later is difficult to be accurately transmitted to the ultrasonic transducer 2, and it is difficult to obtain a stable ultrasonic image. In the case of the above-mentioned spacing, a part of the drive shaft 3 may come into contact with the inner surface of the exterior shaft 4, but since the exterior shaft 4 made of a polyimide resin has a small sliding resistance as described above, this contact causes The rotation and reciprocating motion of the drive shaft 3 are not hindered.

In the present invention, the "minimum interval" means
The minimum distance (distance) from the exterior shaft in the entire drive shaft 3 (when a signal transmission body or the like is integrally provided outside the drive shaft as in the embodiment shown in FIG. 5 described later) , The minimum distance between this signal transmitter and the exterior shaft).

At the base end of the exterior shaft 4, a connector 10 is provided.
Is stuck. The connector 10 is configured to be detachably connected to an external device 30 described later.

Inside the connector 10, two electric contacts 11 and 12 are built. Then, one signal line 6
The base end of the conductor 6a is electrically connected to the electric contact 11, and the base end of the conductor 6a of the other signal line 6 is the electric contact 1.
It is electrically connected to 2.

The external device 30 provided outside the body includes a mechanical drive source 31, a transmission / reception circuit 32, and two electric contacts 3
It has 3, 34. When the connector 10 is connected to the external device 30, the electrical contact 33 contacts the electrical contact 11 on the ultrasonic catheter 1 side, and the electrical contact 34 contacts the electrical contact 12 on the ultrasonic catheter 1 side, and these are electrically connected. . As a result, the electric signal from the transmission / reception circuit 32 is transmitted to the ultrasonic transducer 2 through one of the signal lines 6,
The oscillator 2 emits an ultrasonic wave having a predetermined wavelength, and the ultrasonic wave signal reflected in the body cavity is transmitted to the transmitting / receiving circuit 32 via the other signal line 6. The mechanical drive source 31 mechanically drives the drive shaft 3 to rotate or reciprocate the drive shaft 3. By this driving, radial scanning or linear scanning of the ultrasonic transducer 2 can be performed.

Since the ultrasonic catheter of the present invention can be reduced in diameter, it can be used alone by inserting it into peripheral blood vessels or vessels such as the heart, brain, or lower limbs, and can also be used for angioplasty balloon catheters. It can be used by inserting it into the inner cavity of a therapeutic catheter such as a laser treatment catheter or an atherectomy catheter, and can perform the diagnosis inside the body cavity with an ultrasonic catheter and the treatment with the above-mentioned treatment catheter simultaneously or in parallel.

FIG. 5 is a partially enlarged vertical sectional view showing another embodiment of the present invention. The present embodiment will be described below, but the same components as those of the embodiment shown in FIG.

The drive shaft 3 shown in FIG. 5 is formed in a solid rod shape. Then, the drive shaft 3 integrally has, on the outer side thereof, a signal line 6 which is a signal transmitting body for transmitting a signal between the ultrasonic transducer 2 and the transmission / reception circuit. In this embodiment, the signal lines 6 are spirally wound up to the base end of the drive shaft 3 so as not to overlap each other. As a result, the signal line 6 forms a part of the drive shaft 3 and rotates or reciprocates with it.

The backing material 5 is directly fixed to the tip of the drive shaft 3 with an adhesive or the like, whereby the ultrasonic transducer 2 and the drive shaft 3 are integrally connected.

Such a rod-shaped drive shaft 3 is excellent in mechanical strength such as tensile strength of 20 kgf / mm ² or more, and has a bending outer diameter of at least about 50 cm from the tip side of the ultrasonic catheter 1 at least about 5 cm. It is preferable to have the following flexibility so that it can be restored to its original shape after the bending stress is removed. This is a characteristic required for insertion into small-diameter peripheral blood vessels and vessels such as the heart, brain, and lower limbs. Here, the bending outer diameter refers to an outer diameter that, when deformed by an external force up to a predetermined bending outer diameter, does not substantially cause a kink, and after removing the external force, returns to an almost original shape.

As the constituent material of the drive shaft 3,
For example, stainless steel, substantially 49-58 atomic% Ni
(Remainder Ti) Ni-Ti alloy, Ni-Ti in which a part of this Ni-Ti alloy is replaced by 0.01 to 2.0% X
-X alloy (X is Co, Fe, Mn, Cr, V, A
1, Nb, Pb, B, etc.), substantially 38.5-41.5
Cu-Zn-based alloy of wt% Zn (balance Cu), Cu-Zn-X-based alloy (X is Be, Si, Sn, Al) in which a part of this alloy is replaced with 1 to 10 wt% X, substantially To 36
Super-elastic alloys such as Ni-Al based alloys of up to 38 atomic% Al (the balance Ni), precipitation hardening stainless steels (particularly preferably semi-austenitic PH stainless steels), stainless steels such as maraging stainless steels, high tensile steels. A metal material such as is used. Of these, superelastic alloys such as Ni-Ti alloys are particularly preferable. The superelastic alloy here is generally called a shape memory alloy, and returns to its original shape even after being deformed at least at a living body temperature (around 37 ° C.) to a region where superelasticity (a normal metal causes permanent set). Properties).

Further, in this embodiment, the drive shaft 3
Has an outer diameter of about 0.1 to 0.75 mm, more preferably 0.
It is about 2 to 0.3 mm. The outer diameter of the signal line 6 is 2
It is about 5 to 50 μm.

In this embodiment, the exterior shaft 4
And the minimum distance l between the signal line 6 integrally provided on the outer side of the drive shaft 3 is 100 μm or less. As a result, like the embodiment shown in FIG. 1, the exterior shaft 4
Has a high tensile strength and flexibility, and the drive shaft 3
The sliding resistance when rotating or reciprocating or when being inserted into another catheter such as a treatment catheter is reduced. Therefore, it is possible to provide an ultrasonic catheter having an outer diameter of 1 mm or less, which is excellent in pushability and trackability, can obtain a stable ultrasonic image, and has excellent operability.

FIG. 6 is a partially enlarged vertical sectional view showing another embodiment of the ultrasonic catheter of the present invention. The present embodiment will be described below, but the same components as those in the embodiment shown in FIG.

The ultrasonic catheter 1 of the present invention shown in FIG.
Is an ultrasonic catheter that is used by being inserted into a body cavity, and includes an ultrasonic transducer 2, an ultrasonic reflector 8 that reflects the ultrasonic wave transmitted by the ultrasonic transducer 2 into the body cavity, and an ultrasonic wave. A drive shaft 3 provided on the proximal side of the reflector 8 for transmitting a driving force from a drive source outside the body to the ultrasonic reflector 8 to rotate or reciprocate the ultrasonic reflector; It has a hollow exterior shaft 4 that encloses the sound wave reflector 8 and the drive shaft 3. The exterior shaft 4 is formed of a polyimide resin to have an outer diameter of 1 mm or less and a wall thickness of 50 μm or less. , Exterior shaft 4 and drive shaft 3
It is characterized in that the minimum distance between and is 100 μm or less.

Specifically, the ultrasonic transducer 2 and the backing material 5 are built in the exterior shaft 5, and the distal end side member 14b of the fixing member 14 extending from the proximal end side of the ultrasonic catheter 1 to the vicinity of the distal end. On the back side of the ultrasonic transducer (back material 5
The side) is directed to the tip of the ultrasonic catheter 1 and fixed with an adhesive or the like. The illustrated fixing member 14 is composed of a base end side member 14a, a base end side member 14a and a tip end side member 14b which is a separate member, but may be a single member.

The drive shaft 3 has a solid rod shape, and the ultrasonic reflector 8 is fixed to the tip of the drive shaft 3 with an adhesive or the like. The drive shaft 3 is rotatably supported by a bearing 13 built in the exterior shaft 4. The constituent material of the drive shaft 3,
The dimensions and the like can be the same as those described in the embodiment shown in FIG.

The ultrasonic waves transmitted from the ultrasonic transducer 2 are reflected in the radial direction of the ultrasonic catheter 1 by the reflecting surface 8a of the ultrasonic reflector 8. At the same time, the ultrasonic waves reflected inside the body cavity are reflected by the reflecting surface 8 a of the ultrasonic reflector 8 and reach the ultrasonic transducer 2. The drive shaft 3 is driven by an external mechanical drive source (not shown) to rotate, and the ultrasonic reflector 8 connected to the drive shaft 3 also rotates with it. This allows radial scanning at a desired position within the body cavity.

Although the radial scanning method is used in this embodiment, the bearing 13 is used as described in the embodiment shown in FIG.
It is also possible to reciprocate the drive shaft 3 without providing the above and to enable linear scanning by the ultrasonic transducer 2.

FIG. 7 is a partially enlarged vertical sectional view showing another embodiment of the present invention. In this embodiment, the exterior shaft 4 is
The base end portion 41 has an open front end, and the front end portion 42 is joined to the open front end of the base end portion 41. Other configurations are similar to those shown in FIG.

In this way, by inserting the long drive shaft 3 and other parts into the base end portion 41 of the exterior shaft 4 and assembling them, the front end portion 42 and the base end portion 41 are joined together. The manufacturing of the ultrasonic catheter 1 can be facilitated. Further, the tip end portion 42 can be made of a material different from that of the base end portion 41. Therefore, for example, the tip portion 42 is formed of a material other than the above polyimide resin, such as an olefin resin such as polyethylene or polypropylene, through which ultrasonic waves easily pass, and a more stable ultrasonic image can be obtained. You can
Further, as shown in the figure, the boundary between the base end portion 41 and the tip end portion 42 is set to be substantially near the ultrasonic transducer 2, and the base end portion 41 is
The above polyimide resin, for example, tungsten powder,
A material which is formed by using a mixture of X-ray contrasting materials such as copper, gold, silver, platinum, etc., and the tip portion 42 does not contain the X-ray contrasting member and is capable of passing ultrasonic waves. It is also possible to make the position of the ultrasonic transducer 2, that is, the position measured by the ultrasonic wave in the body cavity, visible by fluoroscopy.

FIG. 8 is a partially enlarged vertical sectional view showing another embodiment of the ultrasonic catheter of the present invention. In this embodiment, a spiral groove 43 is formed at the tip of the exterior shaft 4. By doing so, the flexibility of the exterior shaft 4 can be improved, and the flexibility (flexibility) of the ultrasonic catheter 1 can be improved.

The groove 43 can be formed by subjecting the exterior shaft 4 to laser processing, dicing saw processing, or the like.

The pitch of the grooves 43 is as shown in the figure.
It is preferable to narrow the tip of the catheter. By doing so, the outer shaft 4 can be made softer as it is closer to the tip of the ultrasonic catheter 1, and the flexibility of the ultrasonic catheter 1 can be further improved. Therefore, the operability of the ultrasonic catheter 1 is further improved, the risk of damage to the blood vessel wall due to the catheter tip is reduced, and the ultrasonic catheter 1 can safely travel inside the blood vessel.

As described above, when the pitch of the groove 43 is changed, the pitch is 0.05 to 0.5 at the tip side of the groove 43.
About 0.2 mm, and about 1.0 to 40.0 mm on the base end side is preferable. When the pitch of the grooves 43 is constant,
It is preferable to set it to about 0.5 to 5 mm. In addition, the length of the portion of the exterior shaft 4 that forms the groove 43 is 50 to 30.
It is preferably about 0 mm.

In the illustrated example, the groove 43 has one spiral shape, but it is not limited to this and may have two or more grooves.

The outer diameter of the exterior shaft 4 of this embodiment is gradually reduced from the position separated from the tip by a predetermined length toward the tip. By doing so, in combination with the groove 43, the flexibility (flexibility) of the ultrasonic catheter 1 can be improved.

FIG. 9 is a partially enlarged vertical sectional view showing another embodiment of the present invention. In the present embodiment, a guide member 15 for facilitating the introduction of the ultrasonic catheter 1 into the body cavity is provided at the tip of the exterior shaft 4, and the other configurations are the same as those in FIG.

In this embodiment, the guide member 15 is composed of a coil spring 16 fixed to the tip of the exterior shaft 4. The guide member 15 reduces damage to the body cavity due to the distal end portion of the ultrasonic catheter 1, and allows the ultrasonic catheter 1 to travel safely inside the body cavity.

By providing such a guide member 15, as shown in FIG. 10, the ultrasonic catheter 1 is provided with a treatment catheter 70 (in the illustrated example, a balloon 71 for expanding the narrowed portion of the blood vessel 60 is provided. When using by inserting into the lumen 72 of the angioplasty balloon catheter 70),
The ultrasonic catheter 1 can be preceded, and the therapeutic catheter 70 can be inserted into the body cavity along the ultrasonic catheter 1. Therefore, it is not necessary to prepare a guide wire for guiding the treatment catheter 70 separately from the ultrasonic catheter 1 at the time of insertion into the body cavity, and the operability of the ultrasonic catheter 1 and the treatment catheter 70 is improved. .

As shown in the drawing, the guide member 15 preferably has its outer diameter gradually decreasing toward the tip. Thereby, the flexibility of the guide member 15 can be further improved.

As the constituent material of the coil spring 16 which constitutes the guide member 15, for example, stainless steel, Ni--Ti based alloy of substantially 49 to 58 atomic% Ni (the balance Ni), or this Ni--Ti based alloy is used. 0.01 to 2.0 for a part
% Ni-Ti-X system alloy (X is Co, F
e, Mn, Cr, V, Al, Nb, Pb, B, etc.), substantially 38.5 to 41.5 wt% Zn (balance Cu) Cu
-Zn-based alloy, Cu-Zn-X-based alloy in which a part of this alloy is replaced with 1 to 10 wt% X (X is Be, Si, S
n, Al), substantially 36 to 38 atomic% Al (balance N
i) Superelastic alloy such as Ni-Al alloy, precipitation hardening stainless steel (PH stainless steel is particularly preferably semi-austenitic), stainless steel such as maraging stainless steel, metallic material such as high tensile steel, or Pt, P
An X-ray opaque material such as t alloy, W, W alloy, Ag, or Ag alloy is used.

Of these, Pt, Pt alloy, W, W alloy,
If an X-ray opaque material such as Ag or Ag alloy is used, the guide member 15 that is also the tip of the ultrasonic catheter 1 allows X
The tip position can be easily confirmed under fluoroscopy. If the coil spring 16 is formed of a superelastic alloy such as the Ni-Ti alloy, the guide member 15 can be made more flexible.

When the outer diameter of the coil spring 16 is changed as shown, the outer diameter of the coil spring 16 is 0.2 to 0.
It is preferably about 6 mm and about 0.3 to 1.0 mm on the base end side.
Further, when the outer diameter is constant, it is preferably about 0.3 to 0.5 mm. The length of the coil spring 16 is
It is preferably about 10 to 50 mm. When the coil spring 16 is made of the above superelastic alloy, the buckling strength (yield stress under load) is 5 to 200 kg / mm ² (22
C.), more preferably 8 to 150 kg / mm ² , and the restoring stress (yield stress during unloading) is 3 to 180 kg / mm ^2.
(22 ° C.), more preferably 5 to 150 kg / mm ²
Is.

The coil spring 16 may have a bent shape, and a desired blood vessel may be selected and a blood vessel selective function capable of guiding the ultrasonic catheter 1 to the blood vessel may be added (not shown).

Further, in order to further reduce the risk of damage to the inside of the body cavity due to the tip of the guide member 15, a tip member 17 may be attached as shown in FIG. This tip member 1
7 is formed in the shape of a head piece having a smooth convex curved surface. As the tip member 17, for example, an ultrafine metal wire is heated and melted to form a smooth convex curved surface, or a brazing material is processed into a spherical shape.

At the base end of the tip member 17, the support rod 1
71 is fixed. The support rod 171 extends to the base end side through the inside of the coil spring 16, and the base end is fixed to the exterior shaft 4 via the adhesive 9. As a result, the tip member 17 is fixed to the tip of the guide member 15.
The support rod 171 can improve kink resistance and tensile strength near the tip of the ultrasonic catheter 1.

As the constituent material of the support rod 171, the same material as the constituent material of the coil spring 16 can be used. Moreover, the cross-sectional shape of the support rod 171 may be any shape such as a circle, an ellipse, and a rectangle. Further, the support rod 171 and the tip member 17 may be integrated.

As the adhesive 9, brazing material and various adhesives can be preferably used.

The guide member 15 may be as shown in FIG. In the embodiment shown in FIG. 12, the guide member 15
Is composed of the wire 18 formed of a superelastic alloy such as the above Ni-Ti alloy. With this guide member 15 as well, similar to the embodiment shown in FIG. 9, damage to the body cavity due to the distal end portion of the ultrasonic catheter 1 is reduced, and the ultrasonic catheter 1 can safely travel inside the body cavity.

The outer diameter of the wire 18 is 0.3 to
1.0 mm and length of 10 to 50 mm are preferable, and buckling strength (yield stress under load) is 5 to 200 kg / mm.
² (22 ° C), more preferably 8 to 150 kg / m
m ² , restoration stress (yield stress at unloading) is 3 to 180 k
g / mm ² (22 ° C.), more preferably 5 to 150 k
g / mm ² .

Further, the illustrated wire 18 has a bent shape at its tip end side, and also has a blood vessel selectivity function capable of selecting a desired blood vessel and guiding the ultrasonic catheter 1 to the blood vessel at a branch point of the blood vessel. Have

FIG. 13 is a partially enlarged vertical sectional view showing another embodiment of the present invention. In this embodiment, the ultrasonic catheter 1 is used.
Is provided with a member capable of X-ray contrast.

Specifically, the embodiment shown in FIG.
The structure is almost the same as that of the embodiment shown in FIG.
An X-ray contrastable marker 19 is embedded near the tip of the. Thereby, the position of the ultrasonic catheter 1 in the body cavity can be easily confirmed under fluoroscopy.

As the material of the marker 19, the X-ray opaque material exemplified as the constituent material of the coil spring 13 is preferably used. The length of the marker 19 is
In order to be clearly visible under X-ray fluoroscopy, it is preferable to set the length in the longitudinal direction of the ultrasonic catheter 1 to about mm.

On the tip side of the ultrasonic catheter 1, X
The structure for providing the member capable of radiographic imaging is not limited to the structure shown in FIG. 13, and for example, in the embodiment shown in FIG. 9, the coil spring 16 is formed of an X-ray opaque material as described above. It is also possible to use the coil spring 16 as the X-ray contrast-enable member.

[0088]

As described above, according to the present invention, a stable ultrasonic image can be obtained, and the operability in a body cavity such as a blood vessel or a minute blood vessel or a catheter for various treatments is excellent. An ultrafine ultrasonic catheter can be provided. Therefore, at the time of insertion into the body cavity, it is not necessary to replace the ultrasonic catheter with the treatment catheter, and the risk of damage to the blood vessel wall can be reduced. It can be carried out.

When the polyimide resin contains 5 to 30% of fluorine resin, the sliding resistance of the exterior shaft can be further reduced, a more stable ultrasonic image can be obtained, and the operability is superior. A sonic catheter can be provided.

When a spiral groove is formed from the tip of the outer shaft to a predetermined length, especially when the pitch of the spiral groove is decreased toward the tip direction, the flexibility of the tip portion of the ultrasonic catheter is obtained. Can be further improved, and its operability can be further improved.

When the guide member for the ultrasonic catheter is provided at the tip of the outer shaft, the ultrasonic catheter can be easily introduced to the target site in the body cavity without using a separate guide wire. The operability of the catheter is further improved.

Furthermore, when a member capable of X-ray contrast is provided on the distal end side of the ultrasonic catheter, the position of the distal end of the ultrasonic catheter can be easily confirmed and the operability thereof can be further improved.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional side view showing an embodiment of an ultrasonic catheter of the present invention.

FIG. 2 is an enlarged vertical sectional view showing an ultrasonic transducer and a backing material of the embodiment shown in FIG.

FIG. 3 is an enlarged vertical sectional view showing a modified example of the back material.

FIG. 4 is an end view taken along line IV-IV in FIG.

FIG. 5 is a partial vertical sectional view showing another embodiment of the ultrasonic catheter of the present invention.

FIG. 6 is a partial vertical sectional view showing another embodiment of the ultrasonic catheter of the present invention.

FIG. 7 is a side view of an entire partial cross section showing another embodiment of the ultrasonic catheter of the present invention.

FIG. 8 is a partial cross-sectional side view showing another embodiment of the ultrasonic catheter of the present invention.

FIG. 9 is a partial vertical sectional view showing another embodiment of the ultrasonic catheter of the present invention.

FIG. 10 is an explanatory diagram showing an application example of the ultrasonic catheter of the present invention.

FIG. 11 is a partial vertical cross-sectional view showing another embodiment of the ultrasonic catheter of the present invention.

FIG. 12 is a partial vertical cross-sectional view showing another embodiment of the ultrasonic catheter of the present invention.

FIG. 13 is a partial vertical sectional view showing another embodiment of the ultrasonic catheter of the present invention.

[Explanation of symbols]

 1 Ultrasonic Catheter 2 Ultrasonic Transducer 3 Drive Shaft 4 Exterior Shaft 6 Signal Line 43 Groove 8 Ultrasonic Reflector 31 Mechanical Drive Source 32 Transmitter / Receiver Circuit 15 Guide Member 16 Coil Spring 18 Wire 19 X-Ray Imaging Marker l Minimum Interval

Claims (10)

[Claims] 1. An ultrasonic catheter used by being inserted into a body cavity, comprising an ultrasonic transducer and a driving force provided from a driving source outside the body, which is provided on the proximal side of the ultrasonic transducer. A drive shaft that transmits to the ultrasonic wave oscillator to rotate or reciprocate the ultrasonic wave oscillator, and a hollow exterior shaft that encloses the ultrasound oscillator and the drive shaft. With an outer diameter of 1 mm
Hereinafter, an ultrasonic catheter characterized in that the thickness is formed to 50 μm or less, and the minimum distance between the exterior shaft and the drive shaft is 100 μm or less. 2. An ultrasonic catheter used by being inserted into a body cavity, comprising: an ultrasonic transducer; and an ultrasonic reflector that reflects the ultrasonic waves transmitted from the ultrasonic transducer into the body cavity. A drive shaft which is provided on the proximal side of the ultrasonic reflector and transmits a driving force from a drive source outside the body to the ultrasonic reflector to rotate or reciprocate the ultrasonic reflector; A hollow exterior shaft that encloses the ultrasonic reflector and the drive shaft, and the exterior shaft is made of polyimide resin and has an outer diameter of 1 mm.
Hereinafter, an ultrasonic catheter characterized in that the thickness is formed to 50 μm or less, and the minimum distance between the exterior shaft and the drive shaft is 100 μm or less. 3. The drive shaft integrally has, on the outer side thereof, a signal transmission body that transmits a signal between the ultrasonic transducer and a transmission / reception circuit outside the body. The ultrasonic catheter according to claim 1 or 2, wherein a distance from the exterior shaft is the minimum distance. 4. The ultrasonic catheter according to claim 1, wherein the polyimide resin contains 5 to 30% of a fluorine resin. 5. The ultrasonic catheter according to claim 1, wherein a spiral groove is formed from the tip of the exterior shaft to a predetermined length. 6. The ultrasonic catheter according to claim 1, wherein the pitch of the spiral groove is made smaller toward the distal end. 7. The ultrasonic catheter according to claim 1, wherein a guide member for the ultrasonic catheter is provided at the tip of the exterior shaft. 8. The ultrasonic catheter according to claim 1, wherein the guide member comprises a coil spring fixed to the tip of the exterior shaft. 9. The ultrasonic catheter according to claim 1, wherein the guide member is made of a superelastic metal wire fixed to the tip of the exterior shaft. 10. An X-axis is provided on the tip side of the ultrasonic catheter.
The ultrasonic catheter according to any one of claims 1 to 9, further comprising a member capable of performing line contrast imaging.