JP2000051218A - Direct acting position moving device for ultrasonic catheter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make obtainable a satisfactory tomographic image by controlling the straight movement of the drive shaft of an ultrasonic catheter. SOLUTION: Straight movement at the time of the tomographic image scanning with the drive shaft of the ultrasonic catheter is executed by a direct action driving module 13, which is constituted of a linear stepping motor to be easily moved at the time of manual operation. At the time of driving control, a moving element 7 and a stator element are controlled by pulse waves to provide precise positioning and moving operation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic catheter system which is inserted into a body cavity in a blood vessel or a blood vessel and is used for displaying a sectional image of a lumen or measuring a blood flow.

[0002]

2. Description of the Related Art An ultrasonic catheter is mainly used for treating a vascular stenosis, and it is necessary to select a diameter of a dilatation catheter as a treatment means or to determine whether it is necessary to place a metal tube called a stent. As a help, it is used to observe the condition of the stenosis, and also to observe the condition after treatment.

FIG. 12 is a schematic configuration diagram for explaining the overall configuration of these conventional ultrasonic catheters. The ultrasonic catheter connected to the main unit is connected to a motor built in the scanner unit, and the motor drives the drive shaft. An ultrasonic transducer is provided at the tip of the drive shaft to perform a rotational motion.

[0004] Ultrasonic waves are transmitted from an ultrasonic transducer mounted on the distal end of a body cavity insertion section to be inserted into a body cavity such as a blood vessel, and the echo reflected by a reflector in the subject is subjected to the same ultrasonic wave. 2. Description of the Related Art Ultrasonic diagnostic devices in a body cavity that receive a wave with a sound wave transducer, perform processing such as amplification and detection, and then display the image on a display such as a CRT are widely used for medical purposes.

As described above, an ultrasonic catheter generally obtains an image by rotating and scanning an ultrasonic transducer provided at a distal end portion by a drive shaft. Since the ultrasonic transducer and the drive shaft rotate at a high speed, contact with the blood vessel wall may damage the blood vessel wall or damage the ultrasonic transducer. For this reason, conventionally used ultrasonic catheters are configured such that the ultrasonic transducer and the drive shaft are rotatably accommodated in a catheter sheath and do not contact the blood vessel wall.

An ultrasonic catheter obtains a cross-sectional image of a portion of a blood vessel where an ultrasonic transducer is located, in a direction perpendicular to the axis of the blood vessel. Therefore, the surgeon
In order to observe the state of the vascular stenosis, the ultrasonic catheter is driven so that the distal end where the ultrasonic transducer exists passes through the stenosis. At this time, in order to know the state of the vascular stenosis part in detail, if the stenosis part is repeatedly observed, it is necessary to repeat the passage of the ultrasonic catheter through the vascular stenosis part every time. However,
Since considerable effort is required to pass through the narrowed blood vessel stenosis, repetition of such an operation places a heavy burden on the operator. In order to eliminate such a burden, there has been proposed an ultrasonic catheter having a function of moving only an internal ultrasonic transducer and a drive shaft while a catheter sheath is fixed.
FIG. 13 shows a state in which such an ultrasonic catheter is inserted through a stenotic part of a blood vessel.

[0007] When the operator brings the ultrasonic catheter to the vascular stenosis, the operator pulls the drive shaft while holding the catheter sheath fixed at the intended position,
Observation is performed by passing through the stenosis while moving the ultrasonic transducer to the front. This eliminates the need for the operator to repeatedly insert the sheath of the ultrasonic catheter through the stenosis.

[0008] As a conventional example of a device for moving a motor unit mounted on a base end hub of a drive shaft using a moving means, a technology of a device configuration using a feed mechanism using a ball screw is described in JP-T-7-508204. . A motor and a ball screw are used for a linear movement position moving device of an ultrasonic catheter, and a clutch mechanism is used for switching between an automatic operation state and a manual operation state. In the manual operation state, the clutch is not disengaged and the power is not transmitted from the motor, but the drive shaft and the motor unit can be linearly reciprocated by pushing and pulling.

[0009] The ultrasonic transducer linearly moves back and forth in the catheter sheath, so that it is possible to observe a stenosis part by an ultrasonic image.

[0010]

In a conventional linear motion position moving device using a motor and a ball screw, since the driving section and the driving force transmission mechanism are independent of each other, it is difficult to achieve both miniaturization and high output. As a result, a large device is placed at the foot of the patient, which puts a great burden on the patient and the operator. In addition, the driving force transmission mechanism using a ball screw
Positioning accuracy was poor due to backlash and the like, and it was difficult to accurately grasp the position of the intravascular lesion using an ultrasonic catheter.

Furthermore, switching between automatic operation and manual operation requires a clutch operation, which is troublesome for an operator (doctor or the like) of an ultrasonic catheter.

The present invention has been made in view of the above problems, and employs a direct drive linear motor for a longitudinal position moving device of a drive shaft.
By integrating the motor drive unit and the driving force transmission mechanism, the burden on the patient can be reduced due to the reduction in size and weight.

Further, by enabling manual operation when no voltage is applied to the motor, the operability for switching between the automatic operation state and the manual operation state is improved, and the high precision which is proportional to the minute input pulse voltage to the motor is improved. It is an object of the present invention to provide a linear movement position moving device for an ultrasonic catheter which enables accurate positioning.

Further, in an ultrasonic catheter used for observing a body cavity or a lumen, a drive shaft inserted into a catheter sheath and coupled so as to cooperate with a linear movement position moving device is automatically moved longitudinally. By doing so, during an ultrasound scan by an ultrasound transducer located at the distal end of the drive shaft, 3 in the axially spaced surrounding tissue body within the body cavity or lumen.
It is intended to obtain a data slice of 60 ° in a scanning manner to an arbitrary position.

[0015]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a catheter sheath inserted into a body cavity or a lumen, and a mechanical device inserted into the catheter sheath from a proximal end to a distal end. A drive shaft that transmits a dynamic driving force, and a linear motion position moving device for an ultrasonic catheter having an ultrasonic transducer fixed to the distal end side of the drive shaft, wherein the linear motion position moving device is: A linear actuator for an ultrasonic catheter, comprising: a stator extending in a longitudinal direction; and an operating element for moving the drive shaft in the longitudinal direction, wherein the stator and the operating element constitute a linear motor. The position moving device is the solution.

In this way, it is possible to obtain an ultrasonic tomographic image while controlling the rotation of the drive shaft of the ultrasonic catheter. Since it is possible to move in the longitudinal direction while rotating the drive shaft, a tomographic image at an intended position can be obtained, and three-dimensional information can also be obtained by signal processing of the main unit.

Further, according to this configuration, since there is no need for a feed mechanism relying on mechanical contact, direct operation can be performed directly with a small force in manual operation. In addition, since no gear mechanism is required, the positioning accuracy is improved, and the linear motion is smooth.

The linear motion for an ultrasonic catheter according to claim 1, wherein the operating element has a connecting portion for connecting an end portion of the drive shaft or a member connected to the end portion. The position moving device is the solution.

3. The apparatus according to claim 1, wherein said linear position moving device further comprises a fixing portion for fixing a proximal end of said catheter sheath. Means.

A linear motion for an ultrasonic catheter according to any one of claims 1 to 3, further comprising a shield plate for electrically shielding between said connecting portion and said direct drive type linear motor. The position moving device is the solution.

In this way, when noise is generated due to the drive signal of the direct drive type linear motor or the like, an electric shielding effect can be effectively obtained, and a good ultrasonic tomographic image can be obtained. .

[0022]

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is an overall side view showing an embodiment of a linear movement position moving device for an ultrasonic catheter according to the present invention. FIG. 2 is a sectional view of the distal end of the ultrasonic catheter shown in FIG. FIG. 3 is an enlarged view of a linear drive module of the linear position moving device for an ultrasonic catheter shown in FIG.

The linear movement position moving device 1 for an ultrasonic catheter according to the present invention comprises a catheter sheath 3 inserted into a body cavity,
An ultrasonic catheter 4 having an ultrasonic transducer 4 inserted into a sheath 3 and disposed at a distal end, and further having a drive shaft 5 for transmitting mechanical driving force from a proximal end to a distal end. For linear movement position.

The ultrasonic catheter 2 is connected to a drive shaft rotating unit 6 which is a driving member, whereby the ultrasonic transducer 4 is driven to rotate. The connection with the drive shaft rotation unit 6 is made by a drive shaft connector 9 provided at the base end of the ultrasonic catheter 2.

The linear position moving device 1 has a connecting portion 71 connected to the drive shaft rotating unit 6 connected to the drive shaft 5 in order to slide the base end of the drive shaft 5 integrally. The operator 7 that moves the drive shaft 5 in the longitudinal direction between the positions, and the operator 7 moves in the longitudinal direction in contact with the operator 7, and the drive shaft 5 moves in the longitudinal direction accordingly. Connection module 10 for fixedly connecting a stator 8 for mounting and an outer cylindrical hub 17 at the base of the sheath 3 of the ultrasonic catheter 2
And a housing 23 installed so as to integrate the stator 8 and the fixed connection module 10 with each other.

FIG. 4 is a view of the linear motion drive module 13 of the linear position moving device for an ultrasonic catheter shown in FIG.

FIG. 5 is a view of the linear drive module 13 of the linear position moving device for an ultrasonic catheter shown in FIG.

The operating element 7 and the stator 8 constitute a direct drive type linear stepping motor, and serve as a driving source for moving the drive shaft 5 in the longitudinal direction.
The armature 7 has four wheels 11 in the main body, and has, for example, four band-shaped electromagnetic coils 14 in the center of the main body, and has, for example, five band-shaped permanent magnets at each of the front and rear ends of the main body. 15 is provided. As for the permanent magnet 15, S and N alternate,
In addition, they are arranged with the same space (pitch) as their width. The stator 8 includes a permanent magnet group 16 in which S and N are alternately arranged, and a guide rail 12 provided around the permanent magnet group 16 and guiding the wheels 11 of the operator 7. The permanent magnet group 16 is arranged with the same width and pitch as the permanent magnets 15 of the armature 7.
In addition, the electromagnetic coils 14 of the actuator 7 are arranged so that they have the same width as the permanent magnets 15 and the pitch is about half.

The electromagnetic coil 14 is connected to the permanent magnet group 16 by four
A phase stepping motor is constructed, and P
By transmitting the pulse voltage by the WM control, 1-2 phase excitation is performed to generate S and N magnetic forces. As a result, the actuator 7 generates an attraction and a repulsive force with the permanent magnet group 16,
It moves on the stator 8. The energization of the electromagnetic coil 14 may be performed via a transmission cable line (not shown). However, by performing the energization via the wheels 11 from the left and right guide rails 12 of the stator 8, the cable line that hinders movement is eliminated. It can also be configured as follows.

The permanent magnet 15 interacts with the group of permanent magnets 16 arranged at the same pitch, thereby providing the moving stability of the armature 7 on the stator.

FIG. 6 is an enlarged view showing the structure of the proximal end of the ultrasonic catheter 2. Drive shaft connector 9
Is the inner tube 18, the injection connector 1
9, a joint 20, and the outer cylinder hub 17 is fixed to the base of the catheter sheath 3. Joint 2
Numeral 0 is connected to the base end of the drive shaft 5 so as to be rotatable relative to the injection connector 19, and has a structure connectable to the drive shaft rotation unit 6. Further, between the outer tube hub 17 and the inner tube 18,
An O-ring 21 serving as a sealing material is used to improve the airtightness inside the drive shaft connector 9.

FIGS. 7A and 7B are enlarged views of the fixed connection module 10, and FIGS. 7A and 7B are a front view and a side view, respectively. The fixed connection module 10 is provided with a connection arm 22, and is fixed using the connection arm 22 so as to sandwich the outer cylindrical hub 17.

FIG. 8 is an enlarged view of the control device 24 installed in the housing 23 of the linear position moving device for an ultrasonic catheter shown in FIG. 1 for speed selection for controlling the operation of the linear stepping motor. A dial switch 25 and a motor operation dial switch 26 are provided. Further, an electronic circuit for transmitting a pulse voltage to the electromagnetic coil 14 is incorporated in the control device 24. Dial switch 25 for speed selection and dial switch 26 for motor operation
Is assigned to the electromagnetic coil 14 of the actuator 7 in the linear drive module 13.

Next, the operation method and operation of the present invention will be described.

After connecting the outer tube hub 17 of the ultrasonic catheter 2 to the fixed connection module 10 and connecting the joint 20 of the drive shaft connector 9 to the drive shaft rotation unit 6, the drive shaft rotation unit 6 is connected to the operating element. 7 to the connecting portion 71.

The distal end of the ultrasonic catheter 2 is placed at an arbitrary position in the body cavity and the lumen, and the power switch of the drive shaft rotating unit 6 is turned on. Start sonic scan.

Next, a desired speed is selected by the speed selection dial switch 25, and further, the motor-one operation dial switch 26 is set to START.
Ultrasonic transducer 14 and drive shaft 5
Can be automatically moved to any position in the longitudinal direction, thereby obtaining a 360 ° data slice in an axially spaced surrounding tissue in a body cavity or lumen to any position in a scanning manner. it can.

At this time, if the motor operation dial switch 26 is set to STOP, the drive shaft rotating unit 6 can be moved manually, and the ultrasonic transducer 4 and the drive shaft 5 can be moved to arbitrary positions. You can go back. Then, if the motor operation dial switch 26 is set to START again, the inside of the body cavity or lumen once scanned can be diagnosed again.

Further, the motor operation dial switch 2
If 6 is set to READY, the ultrasonic transducer 4 and the drive shaft 5 can be fixedly held at an arbitrary position, and a detailed diagnosis can be made at an arbitrary position.

FIG. 9 is a schematic view showing a cross-sectional structure of the linear drive module 13 of the linear position moving device for an ultrasonic catheter according to the present invention. The stator 8 provided on the upper surface of the housing 23 of the linear position moving device forms a linear stepping motor with the movable element 7, and generates power for linear driving. The actuator 7 is provided with wheels 11 for smoothly performing a linear motion, and slides on rails 12. With these configurations, the operating element 7 performs a linear motion, and the linear movement position of the drive shaft rotation unit 6 fixed by the connecting portion 71 provided on the operating element 7 is performed.

The inside of the operator 7 has a shield plate 31.
Is provided. By providing the shield plate 31, it is possible to prevent electric noise generated by the linear stepping motor from jumping into the drive shaft rotation unit 6 and affecting the ultrasonic tomographic image. When the shield plate 31 is made of a non-magnetically permeable material, a more effective effect can be obtained, and when the ground is applied to lower the potential, a further effect can be obtained.

FIG. 10 is a control block diagram of the linear position moving device for an ultrasonic catheter according to the present invention. The system of the linear position moving device for an ultrasonic catheter shown in this block diagram is roughly composed of three parts: an image forming part, a drive shaft rotation control part, and a linear position move control part.

The direct-movement-position movement control part is the operator 7
Positioning by PWM control is performed as means for controlling the position. The linear stepping motor is driven in accordance with the number of pulses generated by the pulse generation circuit, and the positioning accuracy by this drive depends on the tooth pitch of the permanent magnets provided in the stator 8 and the operator 7 and the coil pitch provided in the operator 7. It is determined.

As a countermeasure when the operation of the linear stepping motor shows an unintended behavior, a machine which is a mechanical safety measure against overrun in the linear motion direction and detachment of the operator 7 and the stator 8 and the like. A typical stop structure (stopper) is provided (not shown). For this reason, malfunction can be effectively prevented.

Further, a limiter circuit is provided as a countermeasure in case of a sudden increase in the moving speed of the operator 7 suddenly. The sudden increase in the moving speed of the movable element 7 may be caused by a sudden increase in the number of generated pulses due to a failure of the pulse generation circuit, and the speed of the movable element 7 is rapidly increased. In order to prevent malfunction due to such a cause, a limiter circuit is provided in the middle of the path from the pulse generation circuit to the linear stepping motor.

FIG. 11 shows the output of the pulse generation circuit and the output of the limiter circuit in normal and abnormal times. If the number of pulses from the pulse generation circuit suddenly rises due to some problem and exceeds a certain number or more,
The output from the limiter circuit no longer shows the body of the pulse wave (0 Hz). The limiter circuit outputs the signal ON time by extending the signal ON time by a preset time length compared to the input pulse wave, and the interval between adjacent pulse waves is increased by increasing the number of input pulses. (Signal OFF time) becomes narrow, and the signal becomes a continuous ON signal. With this continuous ON signal, the linear stepping motor is not driven and can be effectively stopped, thereby preventing a sudden increase in the speed of the operator 7.

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.

[0049]

According to the linear position moving device for an ultrasonic catheter of the present invention, a complicated mechanism is required for the automatic and manual movement of the ultrasonic transducer and the drive shaft, and for the operation of fixing and holding at an arbitrary position. It can be done with one motor operation switch without using it.

Also, it is very small, lightweight and excellent in operability.
Furthermore, by applying a minute input pulse voltage to the linear motor, high-precision positioning can be performed, which not only reduces the discomfort and fatigue of the operator (doctor, etc.) of the ultrasonic catheter, but also reduces the inside of the blood vessel. , An accurate ultrasonic tomographic image can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of a body cavity ultrasonic diagnostic apparatus according to the present invention.

FIG. 2 is a schematic configuration diagram of a distal end portion of an ultrasonic catheter according to the intracavity ultrasonic diagnostic apparatus according to the present invention.

FIG. 3 is a schematic configuration diagram of an embodiment of an in-body-cavity ultrasonic diagnostic apparatus according to the present invention.

4 is a view of the linear motion drive module 13 of the linear motion position moving device for an ultrasonic catheter shown in FIG.

FIG. 5 is a view of the linear driving module 13 of the linear moving position moving device for an ultrasonic catheter shown in FIG.

FIG. 6 is an enlarged view of a drive shaft connector.

FIG. 7 is an enlarged view of the fixed connection module, and (a) and (b) are a front view and a side view, respectively.

FIG. 8 is an enlarged view of a control device installed in a housing of the linear movement position moving device for an ultrasonic catheter shown in FIG. 1;

FIG. 9 is a schematic view showing a cross-sectional structure of a linear drive module of the linear position moving device for an ultrasonic catheter according to the present invention.

FIG. 10 is a control block diagram of a linear position moving device for an ultrasonic catheter according to the present invention.

FIG. 11 shows the output of the pulse generation circuit and the output of the limiter circuit in a normal state and in an abnormal state.

FIG. 12 is a schematic configuration diagram for explaining the overall configuration of a conventional ultrasonic catheter.

FIG. 13 shows a state in which the ultrasonic catheter is inserted through a stenotic part of a blood vessel.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 3 ... Catheter sheath 4 ... Ultrasonic transducer 6 ... Drive shaft rotation unit 7 ... Operator 8 ... Stator 10 ... Fixed connection module 11 ... Wheel 13 ... Linear drive module

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4C061 AA22 BB08 CC00 DD00 GG15 GG22 NN05 WW16 4C301 AA02 BB28 BB30 BB34 CC01 DD01 EE11 EE13 EE16 EE19 FF09 GA04 GA15 GA16 HH01 JA11 JA19 LL17

Claims (4)

[Claims] 1. A catheter sheath inserted into a body cavity or a lumen, a drive shaft inserted into the catheter sheath to transmit a mechanical driving force from a proximal end to a distal end, and a distal end of the drive shaft. A linear position moving device for an ultrasonic catheter having an ultrasonic transducer fixed to the linear moving position moving device, wherein the linear moving position moving device includes a stator extending in a longitudinal direction,
An actuator for moving the drive shaft in the longitudinal direction, wherein the stator and the actuator constitute a linear motor. 2. The linear motion for an ultrasonic catheter according to claim 1, wherein the actuator has a connecting portion for connecting an end of the drive shaft or a member connected to the end. Position moving device. 3. The linear motion position moving device for an ultrasonic catheter according to claim 1, wherein the linear motion position moving device further includes a fixing portion for fixing a proximal end portion of the catheter sheath. 4. A linear motion for an ultrasonic catheter according to claim 1, further comprising a shield plate for electrically shielding between said connecting portion and said direct drive type linear motor. Position moving device.