JP3786312B2 - catheter - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a catheter.
[0002]
[Prior art]
Since the act of inserting the catheter into the living body is mainly performed under fluoroscopy, the catheter is generally given X-ray contrast properties. In recent years, examinations and diagnosis have been performed by a nuclear magnetic resonance apparatus: MRI (Magnetic Resonance Imaging). With the advancement of technology, a catheter and a guide wire are inserted into the body of a subject while monitoring images by the MRI. It has also become possible to perform medical practices such as examination, diagnosis and treatment.
[0003]
In this case, since the conventional catheter made of an organic polymer material is a non-magnetic material, an image does not appear on the MRI monitor image even in a strong magnetic field of MRI. Further, metal markers such as Au, Pt, and Ir used for visual recognition under fluoroscopy do not appear on the MRI monitor image. Further, although a metal blade portion such as stainless steel used as a reinforcing material at the base end portion is visually recognized, the tip portion needs to be flexible, so there is no reinforcing material and no image appears on the MRI monitor image. As a result, the position of the catheter tip in the living body could not be confirmed accurately.
[0004]
[Problems to be solved by the invention]
The objective of this invention is providing the catheter which can be visually recognized appropriately with the monitor by MRI.
[0005]
[Means for Solving the Problems]
Such an object is achieved by the following inventions (1) to (8).
[0006]
(1) A catheter characterized in that a thin film made of a ferromagnetic material is provided at least at a distal end portion of a catheter main body made of a weak magnetic material or a non-magnetic material.
[0007]
(2) A catheter characterized in that a thin film made of a transition metal or an alloy containing a transition metal is provided at least at the distal end of a catheter body made of a weak magnetic material or a non-magnetic material.
[0008]
(3) A catheter characterized in that a thin film made of nickel or an alloy containing nickel is provided at least at the distal end of a catheter body made of a weak magnetic material or a non-magnetic material.
[0009]
(4) The catheter according to any one of (1) to (3), wherein the thin film is formed by a vapor phase thin film method.
[0010]
(5) The catheter according to any one of (1) to (4), wherein the thickness of the thin film is 0.001 to 2.5 μm.
[0011]
(6) The catheter according to any one of the above (1) to (5), wherein the catheter body is entirely formed of a resin and has a reinforcing layer on a proximal end portion excluding a distal end portion.
[0012]
(7) The catheter according to any one of (1) to (6), wherein a coating layer that covers an outer periphery of at least a portion of the catheter body on which the thin film is provided is formed.
[0013]
(8) In any one of the above (1) to (7), at least the distal end portion of the catheter constitutes a contrast portion that generates an artifact of 1 to 8 times the actual outer diameter in an MRI image photographed by the gradient echo method. The catheter described.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the catheter of the present invention will be described in detail with reference to the preferred embodiments shown in the accompanying drawings. The right side in FIGS. 1 to 4 is referred to as a “base end” and the left side as a “tip”.
[0015]
FIG. 1 is a longitudinal sectional view showing an embodiment of the catheter of the present invention. In the catheter shown in FIG. 1, a ring-shaped thin film 2 is formed on the surface of the distal end portion of the catheter tube 1 so as to cover the outer periphery. The constituent material of the thin film 2 is preferably a ferromagnetic material, and specifically includes a transition metal such as iron, nickel, cobalt, or an alloy containing these (for example, stainless steel). It is nickel that produces the most favorable artifacts. By providing the thin film 2 of such a material, an artifact as described later is obtained in the MRI image. This thin film 2 is, for example, various plating methods (liquid layer film forming method) such as electroplating, hot dipping, electroless plating, vapor phase film forming methods such as vapor deposition, sputtering, ion plating, CVD, PVD, Examples thereof include those formed by a method such as bonding a thin film by rolling or the like, and those formed by the vapor phase film forming method are particularly preferable. The thin film 2 formed by such a method changes the orientation of the atomic arrangement during the film growth process, and exhibits moderate artifacts as described later even if it is a ferromagnetic material. Although the thickness of the thin film 2 is not specifically limited, Usually, it is preferable that it is 0.001-2.5 micrometers, and it is more preferable that it is about 0.01-1.0 micrometer. The thin film 2 in the present embodiment is formed in a ring shape so as to cover the entire circumference of the outer periphery in a band shape on the surface of the distal end portion of the catheter body. In this case, the width W of the thin film 2 is not particularly limited, but is preferably about 0.2 to 10 mm, and more preferably about 0.5 to 5 mm in order to obtain an appropriate artifact. In addition, the formation pattern of the thin film 2 is not limited to the illustrated one. For example, the thin film 2 is formed in a linear shape, a strip shape, a spiral shape along the longitudinal direction of the catheter body, Alternatively, any pattern such as a combination of these patterns and the ring-shaped pattern may be used. Moreover, the thin film 2 is not limited to a single layer, and may be a laminate of a plurality of layers (multilayer thin film). Such moderate artifacts can be appropriately adjusted according to various conditions such as the composition of the catheter coating layer and the thin film 2, the thickness, and the width W.
[0016]
The catheter tube 1 is made of an organic polymer material. Examples of the organic polymer material include nylon, polyether polyamide, polyurethane, and polyimide. Further, in the resin constituting the catheter tube 1, an X-ray opaque material such as barium sulfate, bismuth oxide, or tungsten is used so that the position can be confirmed even when the catheter is used under fluoroscopy. You may mix | blend separately.
[0017]
In FIG. 2, a thin film 2 similar to that in FIG. 1 is formed between an inner layer 3 and an outer layer 4 constituting a catheter tube. The configuration of FIG. 2 is more preferable in terms of peel resistance and biocompatibility of the thin film because the thin film 2 is not exposed on the surface of the catheter. A reinforcing body 5 may be further provided between the inner layer 3 and the outer layer 4. The reinforcing body 5 is made of a braid of fine metal wires such as stainless steel, and improves the torque transmission performance and kink resistance of the catheter tube. Further, in order to prevent the distal end portion of the catheter tube from becoming stiff, the reinforcing body 5 is not provided in an area of about 1 to 20 cm from the distal end of the catheter tube. The fine metal wire constituting the reinforcing body 5 generates an artifact under MRI, like the thin film 2 at the tip. Therefore, the catheter shown in FIG. 2 generates an artifact due to the reinforcing body 5 on the proximal end side and an artifact due to the thin film 2 on the distal end side, so that the entire catheter can be observed well under MRI. The inner layer 3 and the outer layer 4 are made of the same organic polymer material as that of the catheter tube 1 shown in FIG. One or more of the organic polymer materials described above can be used in combination (for example, by laminating two or more layers).
[0018]
FIG. 3 shows a third example in which only the distal end portion of the catheter tube is separately formed and connected to the tube body. In FIG. 3, the tip tip inner layer 6 and the tip tip outer layer 7 are made of a flexible material, and the nickel thin film 2 similar to the above-described embodiment is provided between the layers. The tube body 8 is formed of a resin having a relatively high rigidity. With such a configuration, the MRI contrast portion (thin film 2) of the present invention can be formed while appropriately changing the rigidity of the distal end portion and the proximal end portion.
[0019]
4 is the same as that shown in FIG. 2 except that a plurality of thin films 3 as MRI contrast portions are provided in the axial direction of the catheter tube. By providing a plurality of thin films 2 in this manner, the range that is imaged by MRI can be expanded.
[0020]
The catheter of the present invention can be used for medical acts such as examination, diagnosis and treatment under the operation of a nuclear magnetic resonance apparatus: MRI (Magnetic Resonance Imaging). The catheter of the present invention is 1 to 8 times, more preferably 1.5 to 7.5 times, more preferably 2 to 7 times the outer diameter of the actual catheter in the MRI image taken by the gradient echo method. It has a contrast part that produces artifacts. If the artifact is too large, it is difficult to confirm the position of the catheter in the body cavity. If the artifact is too small, the artifact may be difficult to see in an MRI image obtained by the spin echo method, which is another MRI imaging method. This contrast portion is preferably present at least at the distal end portion of the catheter.
[0021]
The specific structure of the catheter of the present invention is not particularly limited as long as it has an imaging part having the above-mentioned characteristics. Examples of applicable catheters include PTCA expansion catheters, guiding catheters, angiographic catheters, and the like. Vascular catheters, introducer sheaths, trocars, gastric tube catheters, endotracheal tubes, endoscopic tubes, ultrasonic catheters, ureteral catheters, and other various catheters used in the human body.
[0022]
【Example】
Hereinafter, specific examples of the present invention will be described in detail.
[0023]
Example 1 A catheter having the structure shown in FIG. 1 was manufactured. Each condition of this catheter is as follows.
[0024]
Total length of catheter: 90cm
Constituent material of the catheter: Barium sulfate (40 wt%) polyurethane catheter body outer diameter: 1.4 mm
Thin film composition: Ni-Co-Cr-Al-Cu alloy Thin film shape: Ring-shaped thin film dimensions: Width 2 mm, thickness 0.05 μm
Forming position of thin film: The center of the thin film in the width direction is 3 mm from the tip of the catheter body. Forming method of thin film: Bonding the rolled thin film (Example 2) A catheter having the structure shown in FIG. Each condition of this catheter is as follows.
[0025]
Total length of catheter: 90cm
Constituent material of catheter: inner layer / barium sulfate containing (40 wt%) nylon 12, outer layer / polyether polyamide block copolymer catheter outer diameter: 1.4 mm
Thin film composition: Ni (nickel)
Thin film shape: Ring-shaped thin film dimensions: Width 2 mm, thickness 0.05 μm
Thin film formation position: The center of the thin film in the width direction is 3 mm from the tip of the catheter body. Thin film formation method: Vapor deposition reinforcement: Stainless steel braid (comparative example)
A catheter similar to Example 1 was produced except that no thin film was provided.
[0026]
<Experiment 1>
About what put each catheter of Examples 1-2 and Comparative Example 1 in water, it photographed by the gradient echo method using MRI (the GE Medical company make, magnetic field: 0.2T (Tesla)), and the MRI image Monitored. In the catheter of Example 1, the actual catheter contour (solid line in FIG. 5) and the guide wire artifact 9 (shaded portion in FIG. 5) appearing in the MRI image are shaped as shown in FIG. A schematic diagram is shown). Further, in the catheter of Example 2, the actual catheter contour (solid line in FIG. 6) and the guide wire artifact 10 (shaded portion in FIG. 6) appearing in the MRI image are as shown in FIG. It became a shape (schematic diagram is shown). On the other hand, in the catheter of Comparative Example 1, the actual contour of the catheter was very unclear in the MRI image and was difficult to visually recognize. From the MRI image, the magnification of the artifact (average value of each part) with respect to the actual outer diameter of the contrasted part of the catheter was measured, and the following results were obtained.
[0027]
Example 1: 5.1 times Example 2: 5.6 times Comparative Example 1: Not Appearing From the above results, in the catheters of Examples 1 and 2, in the MRI monitor image, the position of the catheter, particularly the tip portion It was confirmed that the position and shape can be grasped more accurately.
[0028]
【The invention's effect】
As described above, according to the catheter of the present invention, the position and shape of the catheter, in particular, the position of the distal end portion can be properly visually recognized on the monitor image by MRI, and the flexibility of the distal end portion is not impaired. . Therefore, when a medical action such as examination, diagnosis, treatment or the like is performed while using the catheter of the present invention under the MRI monitor, the medical action can be performed smoothly and appropriately.
[0029]
In particular, in the present invention, by setting conditions such as the composition, dimensions, formation position, and formation pattern of the thin film, the size of the artifact with respect to the actual outer diameter of the catheter and the site where the artifact occurs can be appropriately adjusted, and desired characteristics can be obtained. Can be easily obtained.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an embodiment of a catheter of the present invention.
FIG. 2 is a cross-sectional view showing another example of the catheter of the present invention.
FIG. 3 is a cross-sectional view showing a third example of the catheter of the present invention.
FIG. 4 is a cross-sectional view showing a fourth example of the catheter of the present invention.
FIG. 5 is a schematic diagram showing the outline of a catheter (the present invention) and the shape of catheter artifact in an MRI image.
FIG. 6 is a schematic diagram showing the outline of a catheter (invention) and the shape of the catheter artifact in the MRI image.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Catheter tube main body 2 Thin film 3 Inner layer 4 Outer layer 5 Reinforcement body 6 Tip tip inner layer 7 Tip tip outer layer 8 Catheter tube main body 9, 10 Artifact

Claims (7)

Oite to at least the tip portion of the catheter body consisting configured inner and outer layers of an organic polymeric material, a catheter, characterized in that a ring-shaped thin film made of a ferromagnetic material between the layers of the inner and outer layers. Oite to at least the tip portion of the catheter body consisting configured inner and outer layers of an organic polymeric material, by providing a ring-shaped thin film made of an alloy containing a transition metal or transition metal layers of the inner and outer layers A catheter characterized by. Oite to at least the tip portion of the catheter body consisting configured inner and outer layers of an organic polymer material, characterized in that a ring-shaped thin film made of an alloy containing nickel or nickel layers of the inner and outer layers And catheter. The catheter according to any one of claims 1 to 3, wherein the thin film is formed by a gas phase thin film method. The catheter according to any one of claims 1 to 4, wherein a reinforcing layer is provided between the inner layer and the outer layer in a proximal end portion excluding a distal end portion of the catheter body. The catheter according to claim 5, wherein the reinforcing body is formed of a braid of fine metal wires. The catheter according to any one of claims 1 to 6, wherein the thin film has a width of 0.2 to 10 mm and a thickness of 0.001 to 2.5 µm.

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