JP3571939B2 - Ultrasound catheter - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an ultrasonic catheter which is inserted into a body cavity such as a blood vessel or a blood vessel and used for observing or diagnosing a cross-sectional image of a lumen.
[0002]
[Prior art]
As a treatment for a vascular stenosis causing a myocardial infarction or the like, a surgical technique of performing a percutaneous treatment using a catheter has been performed. This surgical technique includes a method of pushing and expanding a stenosis with a dilatation catheter having a balloon at the tip, a method of placing a metal tube called a stent, and a method of rotating a grindstone or a cutter with a device called a rotablator (trademark) to remove the stenosis. There are various methods such as a resection method, and a preferable method is selected according to the properties of the stenosis and the condition of the patient. Ultrasound catheters are mainly used during percutaneous treatment of such vascular stenosis, observing the properties of the stenosis, and used as an aid in making decisions for the selection of treatment means. It is also used for observations. Therefore, the ultrasonic catheter is required to be able to pass through a stenosis part of the blood vessel.
[0003]
Generally, an ultrasonic catheter is connected to a driving device having a built-in motor, and the motor drives a drive shaft to rotate. An ultrasonic transducer is provided at the tip of the drive shaft to perform a rotary motion. Ultrasonic waves are transmitted from an ultrasonic transducer inserted into a body cavity such as a blood vessel along with such a rotational movement, and the echo reflected within the subject is received by the same ultrasonic transducer, and amplification and detection are performed. After the processing, the image is displayed as an image on a display such as a CRT.
[0004]
As described above, the ultrasonic catheter generally obtains an image by rotating and scanning the ultrasonic transducer provided at the distal end by the drive shaft. Since the ultrasonic transducer and the drive shaft rotate at a high speed, when the ultrasonic transducer and the drive shaft come into contact with the blood vessel wall, there is a risk of damaging the blood vessel wall or damaging the ultrasonic transducer. For this reason, conventionally, the ultrasonic catheter is configured such that the ultrasonic transducer and the drive shaft are rotatably accommodated in the catheter sheath and do not contact the blood vessel wall.
[0005]
The ultrasonic transducer is fixed to a housing provided at the tip of the drive shaft. As a housing for holding the ultrasonic transducer, a housing made of a cylindrical pipe having an outer diameter substantially equal to that of the drive shaft is used in order to reduce sliding resistance in the catheter sheath. In addition, if the center of gravity of the housing to which the ultrasonic transducer is fixed is located at an eccentric position, there is a possibility that rotation unevenness of the drive shaft may be caused. Therefore, the ultrasonic transducer rotates inside the opening provided in the side wall of the housing. It is preferable to be installed so as to be located near the center in the axial direction. For this reason, the ultrasonic irradiation surface of the ultrasonic transducer is retracted in the direction of the rotation axis from the outer surface of the housing, and a step is generated between both surfaces.
[0006]
[Problems to be solved by the invention]
Here, in order to transmit and receive ultrasonic waves from the ultrasonic transducer, it is necessary that an ultrasonic wave propagating substance such as physiological saline is present in the catheter sheath. For this reason, a priming operation of injecting a liquid such as a physiological saline solution from a port provided in the connector at the proximal end of the catheter is usually performed before the operation, and the inside of the catheter sheath is filled with the ultrasonic wave transmitting substance.
[0007]
However, it is difficult to completely replace the air inside the catheter sheath with saline even with an ultrasonic catheter that has been primed before surgery, and the air remaining inside the catheter sheath becomes bubbles. May be present. In particular, air bubbles tend to remain on the surface of the ultrasonic transducer having a step with the outer surface of the housing, and the ultrasonic waves are not propagated by the air bubbles, so that image quality may be degraded. Usually, in such a case, an operation of injecting (flushing) a physiological saline solution from the above-described port provided in the catheter connector to the lumen at the distal end of the catheter to remove air bubbles is performed.
[0008]
However, once air bubbles flow into the surface of the ultrasonic transducer, the air bubbles stay at the step with the housing due to the surface tension of the liquid surface of the air bubbles, and it is difficult to remove the air bubbles even when flushing is performed. In many cases, the image quality is degraded, which causes discomfort and fatigue of the operator. In particular, the smaller the diameter of the ultrasonic catheter, the smaller the clearance (clearance) between the inner surface of the catheter sheath and the outer surface of the drive shaft or housing, so that the fluid pressure due to flushing is less likely to be transmitted to the ultrasonic transducer, and this phenomenon is remarkable. Appears in
[0009]
The present invention has been made in view of such a problem, and it is difficult for air bubbles to stay on the surface of the ultrasonic transducer even if the diameter is small. It is an object of the present invention to provide an ultrasonic catheter from which a favorable image can be obtained.
[0010]
[Means for Solving the Problems]
In order to solve the aforementioned problems, the present invention provides a catheter sheath inserted into a body cavity or a lumen, and a drive that is inserted into the catheter sheath and transmits a mechanical driving force from a proximal end to a distal end. In an ultrasonic catheter having a shaft, a housing provided on the distal end side of the drive shaft, and an ultrasonic transducer fixed to the housing, the housing has an opening in a side wall of a cylindrical main body, The ultrasonic transducer is fixed inside the opening, and the ultrasonic transducer is covered at least on the distal end side and the proximal end side in the catheter sheath longitudinal direction by fixing means. A communication hole for communicating with an ultrasonic irradiation surface of the ultrasonic transducer; With ether and the solutions.
[0011]
Here, a coil-shaped body is provided at the tip of the housing, and the tip of the coil-shaped body is open, and the opening from the open end of the coil-shaped body communicates with the ultrasonic irradiation surface of the ultrasonic transducer. Is preferred.
[0012]
Preferably, a priming injection hole is provided at the distal end of the catheter sheath.
[0013]
Further, it is preferable that an outer diameter of the catheter sheath at a position where the ultrasonic transducer is located is 0.8 mm or less.
[0014]
Further, it is preferable that the fixing means further has a communication hole for communicating a base end of the housing and an ultrasonic irradiation surface of the ultrasonic transducer.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0016]
FIG. 1 is a side view showing an overall image of an ultrasonic catheter according to the present invention. In FIG. 1, an ultrasonic catheter 1 includes a catheter sheath 2 inserted into a body cavity or a lumen, and a connector 3 for connecting to an external drive source (not shown). It comprises a connected sheath connector 3a and a drive shaft connector 3b connected to an ultrasonic transducer via a drive shaft described later. A priming hole 4 is provided at the distal end of the catheter sheath 2. The flushing port 31 is provided in the sheath connector 3a, but is plugged except when flushing is performed. The drive shaft connector 3b is provided with a confirmation port 32 for confirming the end of priming, which is also usually plugged.
[0017]
The catheter sheath 2 has a multilayer structure of a resin such as polyimide, polyamide, polyester, polyethylene, polyurethane, or the like. A metal braid is formed between the resin layers at a base end of the lumen where the ultrasonic transducer is located. And a reinforcing body such as a coil.
[0018]
FIG. 2 is a sectional view of the distal end portion of the ultrasonic catheter 1 according to the embodiment shown in FIG. In FIG. 2, reference numeral 5 denotes a hollow drive shaft composed of a coil, and a cylindrical housing 6 is fixed to the tip of the drive shaft. An opening 14 is provided in the side wall of the housing 6, and the ultrasonic transducer 7 is fixed inside the opening 14. The distal end of the housing 6 is further provided with a coil-shaped body 8. The coiled body 8 improves the rotational stability of the drive shaft 5 and the ultrasonic transducer 7, prevents bending (kinking) at the distal end of the catheter sheath 2, and fixes the ultrasonic transducer 7 with the catheter sheath 2 fixed. When the is moved in the axial direction, the housing can be prevented from contacting the catheter sheath 2. The distal end of the drive shaft 5 and the base end of the coil-shaped body 8 are inserted into the housing 6 and fixed or welded from the surface of the joint with a fixing material 12 such as solder or adhesive, so that a strong fixing is possible. It becomes. Reference numeral 13 denotes a signal line for connecting the ultrasonic transducer 7 to an external electric circuit, and extends inside the hollow drive shaft 5 to the end of the connector 3 at the base end of the ultrasonic catheter 1. Reference numeral 22 denotes an X-ray opaque marker for confirming the position of the distal end of the ultrasound catheter 1 under X-ray fluoroscopy when inserted into a body cavity, and is made of a metal having high X-ray opacity such as Pt, Au, and Ir. You.
[0019]
Inside the housing 6, the ultrasonic transducer 7 has a back material 9 made of epoxy, urethane, acrylic resin or the like or a resin mixed with metal or inorganic powder on the back side of the ultrasonic transducer 7, excluding the ultrasonic irradiation surface. The entire circumference is fixed by fixing means 10 made of a resin adhesive such as an ultraviolet curable adhesive. In the case of a thin ultrasonic catheter in which the diameter of the catheter sheath 2 is 0.8 mm or less, at least the longitudinal direction of the ultrasonic transducer 7 in addition to the lower surface of the back material 9 in order to obtain a sufficient bonding area. It is preferable to further bond the distal end side and the proximal end side. The fixing means 10 is provided with a communication hole 11 for communicating the tip of the housing 6 and the ultrasonic irradiation surface of the ultrasonic transducer 7.
[0020]
The housing 6 is made of a nonconductive material or the like made of a ceramic material such as alumina or zirconia, and has a cylindrical pipe having an outer diameter substantially equal to that of the drive shaft 5 in order to reduce sliding resistance with the inside of the catheter sheath 2. Consists of The ultrasonic transducer 7 is formed by depositing and printing electrodes on both surfaces of a rectangular or circular piezoelectric material made of PZT or the like. The installation position of the ultrasonic transducer 7 is set such that the center of gravity of the housing 6 in a state where the ultrasonic transducer 7 and the backing material 9 are incorporated is near the center in the rotation axis direction so that the drive shaft 5 does not cause rotation unevenness. Installed in a location.
[0021]
FIG. 3 is a diagram for explaining a method for providing the communication hole 11 in the fixing means 10. First, an opening 14 is formed in the side wall of the housing 6 formed of a cylindrical pipe, and a small-diameter wire 15 made of stainless steel or the like is inserted through the distal end of the drive shaft 5. Next, the ultrasonic transducer 7 to which the back member 9 is attached is inserted into the opening 14, and an appropriate amount of resin adhesive is caused to flow on the front and rear ends of the ultrasonic transducer 7. The resin adhesive closes both ends of the housing 6 and covers almost the entire periphery of the ultrasonic transducer 7 and the back member 9 except for the ultrasonic irradiation surface. At this time, the wire 15 is connected to the front end portion of the housing 6 from the ultrasonic irradiation surface of the ultrasonic transducer 7 in the resin adhesive near the ultrasonic irradiation surface at an angle substantially parallel to the ultrasonic irradiation surface of the ultrasonic transducer 7. Place and fix so that Then, after the resin adhesive is cured to form the fixing means 10, the wire 15 is pulled out to secure a communication hole 11 communicating from the tip of the housing to the ultrasonic irradiation surface. As the resin adhesive, it is preferable to use a polyacetal, PTFE, or polyethylene resin adhesive, particularly an ultraviolet-curable resin adhesive, from which the wire 15 can be pulled out after curing. If a release agent is applied or coated on the surface of the wire 15 in advance, a metal-based adhesive material can be used.
[0022]
When the drive shaft 5 is formed of a relatively loosely wound coil body, the priming liquid also flows into the drive shaft, so that a communication hole similar to the communication hole 11 is provided on the drive shaft 5 side of the fixing means 10. May be provided. Thereby, the liquid flow at the time of priming becomes easier to flow near the irradiation surface of the ultrasonic transducer 7.
[0023]
FIG. 4 is a side sectional view illustrating the structure of the proximal end portion of the ultrasonic catheter 1 according to the present invention. In FIG. 4, the drive shaft connector 3b is connected to the proximal end of the drive shaft 5, and can move the ultrasonic transducer 7 to the proximal side relative to the catheter sheath 2. The drive shaft connector 3b includes a guide tube 16 slidable inside the sheath connector 3a while covering a predetermined portion at the base end of the drive shaft 5. The guide tube 16 is for preventing the base end portion of the drive shaft 5 from being exposed to the outside when the drive shaft 5 is pulled. The guide tube 16 has an inflatable portion 17 at its distal end, and the guide tube from the sheath connector 3a. 16 is prevented from falling off.
[0024]
The sheath connector 3a is connected to the rear end of the catheter sheath 2 at a connection port 18, and has an O-ring-shaped seal for maintaining airtightness between the sheath connector 3a and a drive shaft connector 3b inserted into the sheath connector 3a. The seal member 19 includes a member 19 and a screw portion 20, and the seal member 19 is gripped by connecting the screw mechanism provided to the pusher 21 to the screw portion 20.
[0025]
The base end of the drive shaft connector 3b is detachable from a motor drive device described later, and the rotation terminal 23 rotates together with the drive shaft 5 by fitting with the motor drive device.
[0026]
FIG. 5 is a cross-sectional view for explaining a connection structure between the drive shaft connector 3b and the motor driving device of the ultrasonic catheter 1 according to the embodiment shown in FIG. The drive shaft 5 incorporates a twisted pair of signal lines 13, the distal end of which is connected to the ultrasonic transducer 7 as described above, and the base end of which is a metal rotary terminal 23 and a concave terminal. 24. The drive shaft connector 3b is detachably connected to a locking portion 41 of a drive shaft rotation unit 40 which is a motor driving device. The concave terminal 24 is detachably connected to the convex terminal 42 of the drive shaft rotating unit 40 so as to transmit the driving force from the motor to the drive shaft 5, and then electrically connected to a transmitting / receiving circuit (not shown) via a slip ring or the like. Make a connection. The drive shaft rotation unit 40 includes a drive source including a transmission / reception circuit and a motor, and the concave terminal 24 and the convex terminal 42 rotate in a connected state. The drive shaft rotation unit 40 is further electrically connected to a console having a signal processing circuit and an image display device.
[0027]
In scanning of the ultrasonic wave in the ultrasonic catheter 1 of the present invention, the rotational motion of the motor in the drive shaft rotation unit 40 is transmitted to the drive shaft 5 via the concave terminal 24 and is fixed to the tip of the drive shaft 5. By rotating the housing 6, the ultrasonic waves transmitted and received by the ultrasonic transducer 7 provided in the housing 6 are scanned in a substantially radial direction. The ultrasound image obtained here is a transverse cross-sectional image inside the blood vessel. Further, by pulling the entire ultrasound catheter 1 or the drive shaft connector 3b toward the hand side and moving the drive shaft 5 in the longitudinal direction, a 360 ° cross-sectional image of the surrounding tissue body spaced apart in the axial direction in the blood vessel is obtained. Can be obtained by scanning to an arbitrary position.
[0028]
Next, a procedure for operating the ultrasonic catheter 1 of the present invention in a blood vessel will be described. The ultrasonic catheter 1 of the present invention is inserted into a dedicated holder tube (not shown), and the sheath connector 3a and the drive shaft connector 3b are brought into contact. Next, when physiological saline is injected as a priming liquid from the end of the holder tube on the distal side of the ultrasonic catheter, the inside of the catheter can be filled with the physiological saline from the priming hole 4 provided at the distal end of the ultrasonic catheter 1. The injection of the physiological saline is performed until the physiological saline flows out from the priming completion confirmation port 32 provided on the drive shaft connector 3b. Here, a clear image having no bubbles on the ultrasonic irradiation surface may be confirmed by a monitor device (not shown). In the case of an ultrasonic catheter having a small diameter and a small gap (clearance) between the housing 6 and the catheter sheath 2 as in the present invention, the priming is performed from the distal end side of the catheter sheath 2 in this manner, so that the distal end is Since the water pressure near the surface of the ultrasonic transducer 7 located in the portion can be made relatively high, it is easy to remove bubbles. Further, in the present invention, the priming liquid flows into the surface of the ultrasonic transducer 7 from the communication hole 11 and bubbles are less likely to remain on the surface of the ultrasonic transducer, so that the time required for priming to be completed is reduced. .
[0029]
Next, a method for inserting and placing the ultrasonic catheter 1 of the present invention into a blood vessel will be described. Basically, the procedure is the same as a normal vascular catheter procedure. First, an introducer or the like is inserted through the thigh or the upper arm to secure a blood vessel and a passage outside the body. Subsequently, a guiding catheter for contrast or an inspection or treatment catheter is inserted into the blood vessel with a guide wire while selecting the blood vessel, and after reaching the entrance site of the target blood vessel (coronary artery) to be inspected or treated, The ultrasonic catheter 1 of the present invention is inserted into a guiding catheter.
[0030]
After the distal end of the ultrasonic catheter 1 reaches the target site to be inspected or treated, the drive shaft rotating unit 40 is driven to rotate the drive shaft 5 and the ultrasonic transducer 7 and start an ultrasonic scan. Next, by moving the drive shaft connector 3b to an arbitrary position in the longitudinal direction manually or automatically by a drive shaft rotating unit linear movement moving device (not shown), the distance in the axial direction in the body cavity or lumen is increased. A 360 ° cross-sectional image of the surrounding tissue body with a space can be obtained by scanning to an arbitrary position.
[0031]
At this time, when the ultrasonic transducer 7 passes through the air bubbles scattered inside the catheter sheath 2, the air bubbles flow into recesses between the housing 6 and the ultrasonic irradiation surface of the ultrasonic transducer 7, There is a case where the ultrasonic wave is not propagated from the ultrasonic transducer 7 and the image quality is deteriorated. In such a case, physiological saline is injected under pressure (flushing) from the flushing port 31 provided on the rear end side of the catheter toward the distal end of the catheter. FIG. 6 schematically shows such a state. In the comparative example in which the communication hole is not provided, the flow of the physiological saline does not reach the corner of the surface of the ultrasonic transducer 7, so that the bubble 50 tends to stay. On the other hand, in the case where the communication hole 11 is provided as in the embodiment of the present invention, the priming liquid flows into the communication hole 11 from the ultrasonic irradiation surface, and the bubbles 50 do not stay in the concave portion of the housing 6. Can be easily discharged.
[0032]
As described above, according to the ultrasonic catheter of the present invention, it is difficult for air bubbles to remain on the ultrasonic irradiation surface due to priming, and even if air bubbles remaining in the catheter sheath 2 flow during operation, flushing occurs. Since the priming liquid flows into every corner of the ultrasonic irradiation surface, bubbles can be easily discharged without staying on the ultrasonic irradiation surface. Therefore, the deterioration of the image quality due to the bubbles can be easily improved.
[0033]
Further, since the priming solution can easily flow into the ultrasonic irradiation surface, the time required for priming performed before the operation can be shortened, and the discomfort and fatigue of the operator can be reduced.
[0034]
It should be noted that the embodiments described above are described for facilitating the understanding of the present invention, and are not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.
[0035]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, since the priming liquid flows into the step part (recess part) of a housing and an ultrasonic transducer easily, the time required for priming performed before operation can be shortened. Even if air bubbles adhere to the ultrasonic irradiation surface of the ultrasonic transducer, the priming liquid flows from the ultrasonic irradiation surface to the communication hole due to flushing, so that the air bubbles can be easily retained on the ultrasonic irradiation surface. Can be discharged. Therefore, it is possible to easily improve the deterioration of the image quality caused by the bubbles, and to reduce the discomfort and fatigue of the operator.
[Brief description of the drawings]
FIG. 1 is a side view showing an ultrasonic catheter according to the present invention.
FIG. 2 is a sectional side view of a distal end portion of the ultrasonic catheter according to the present invention.
FIG. 3 is a view for explaining a method of providing a communication hole in a housing of the ultrasonic catheter according to the present invention.
FIG. 4 is a side sectional view for explaining a structure of a proximal end portion of the ultrasonic catheter according to the present invention.
FIG. 5 is a cross-sectional view for explaining a connection structure of the ultrasonic catheter according to the present invention with a motor driving device.
FIG. 6 is a diagram for explaining a difference in the state of bubbles during flushing between the ultrasonic catheter according to the present invention and a comparative example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Ultrasonic catheter 2 ... Catheter sheath 3 ... Connector 3a ... Sheath connector 3b ... Drive shaft connector 4 ... Priming hole 5 ... Drive shaft 6 ... Housing 7 ... Ultrasonic transducer 8 ... Coiled body 9 ... Back member 10 ... Fixing means 11 communication hole 12 fixing member 13 signal line 14 opening

Claims (5)

A catheter sheath inserted into a body cavity or a lumen, a drive shaft inserted into the catheter sheath and transmitting a mechanical driving force from a proximal end to a distal end, and a housing provided at the distal end of the drive shaft And, in an ultrasonic catheter having an ultrasonic transducer fixed to the housing, the housing has an opening in a side wall of a cylindrical body, the ultrasonic transducer is fixed inside the opening, The ultrasonic transducer has at least a distal end side and a proximal end side in a longitudinal direction of the catheter sheath covered by a fixing means, and the fixing means has a communication for communicating a distal end of the housing and an ultrasonic irradiation surface of the ultrasonic transducer. An ultrasonic catheter having a hole. A coil-shaped body is provided at the tip of the housing, and the tip of the coil-shaped body is open, and the ultrasonic irradiation surface of the ultrasonic transducer communicates from the opened tip of the coil-shaped body. The ultrasonic catheter according to claim 1, wherein The ultrasonic catheter according to claim 1, wherein a priming injection hole is provided at a distal end portion of the catheter sheath. The ultrasonic catheter according to claim 1, wherein an outer diameter of the catheter sheath at a position where the ultrasonic transducer is located is 0.8 mm or less. The ultrasonic catheter according to claim 1, wherein the fixing means further includes a communication hole that communicates a base end of the housing and an ultrasonic irradiation surface of the ultrasonic transducer.

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