JPH0630937A - Ultrasonic diagnosing apparatus - Google Patents

Abstract

PURPOSE:To provide an ultrasonic diagnosing apparatus which enables the obtaining of a Z phase signal reflecting the position of physical rotation of an ultrasonic vibrator without altering an outer diameter size of an ultrasonic probe nor extension of a dedicated signal line. CONSTITUTION:A hetero material part 5 with acoustic impedance different from material used for a probe sheath 3 is provided partly in the circumferential direction of the probe sheath. A signal identification means is provided to identify an ultrasonic echo signal reflected from a probe sheath material from an ultrasonic echo signal reflected from the hetero material part 5. A writing start signal of an ultrasonic image is generated based on the signal identified by the signal identification means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic diagnostic apparatus, and more particularly to projecting ultrasonic pulses to a living body,
The present invention relates to an ultrasonic diagnostic apparatus that receives the ultrasonic echo and obtains an ultrasonic image.

[0002]

2. Description of the Related Art In recent years, an ultrasonic diagnostic technique has been widely used in which ultrasonic waves are applied to the inside of a body and the state of the inside of the body is drawn from the echo signal to detect and diagnose a lesion. Among them, the method of inserting the ultrasonic probe into the body endoscopically and irradiating the lesion part with ultrasonic waves from the body has less attenuation of ultrasonic waves than the method of irradiating ultrasonic waves from outside the body, and Since ultrasonic waves can be used, it has attracted attention because it can obtain ultrasonic images with high resolution.

In such an intracorporeal ultrasonic diagnostic apparatus, a so-called radial scan in which the ultrasonic transducer is rotated about the lumen axis of the body to radially scan the ultrasonic beam to obtain a cross-sectional image of the lumen The method is the most effective for diagnosis. Further, while performing a radial scan, an ultrasonic transducer is moved in the axial direction of the probe to capture a plurality of cross-sectional images, image processing is performed to construct a three-dimensional image, and attempts have been made to improve diagnostic ability. .

An ultrasonic diagnostic apparatus of the mechanical radial scan type normally transmits a rotation of a flexible shaft or the like to a motor provided inside a drive unit outside the body and an ultrasonic transducer at the tip of a probe inserted into the body. It is configured to be connected by a member, and the outer periphery thereof is covered with a cylindrical resin sheath. In addition, a rotation detecting means such as a rotary encoder is provided in the drive unit, and stable and accurate radial scan sectional image can be drawn by obtaining rotation information of the vibrator. In addition, the position where the cross-sectional image is displayed is from the rotary encoder to 1
It is determined by the image formation start position signal that outputs one pulse per rotation.

Further, in order to perform a three-dimensional scan, a drive mechanism for moving the flexible shaft back and forth in the axial direction of the probe is provided, and a radial scan and a linear scan are performed in combination.

[0006]

However, in the normal ultrasonic probe, the rotation detecting means for detecting the rotation of the ultrasonic transducer is provided in the drive unit on the hand side, and the rotation detecting means An ultrasonic transducer provided at the tip of the probe is connected by a rotating member such as a flexible shaft. Therefore, the rotation detecting means in the drive unit does not always accurately reflect the rotation of the ultrasonic transducer. Especially when the probe sheath bends, the frictional force generated between the inner surface of the probe sheath and the flexible shaft changes, causing uneven rotation of the ultrasonic transducer and physical rotation of the probe tip. The positional relationship between the position and the image generation start position signal of the ultrasonic image output by the rotary encoder changes,
As a result of the change of the image drawing position, a phenomenon occurs that the image is rotated. When a normal radial scan is performed under such a condition, each time the probe bends, the displayed image rotates and it becomes very difficult to orient the diagnosis. Further, when performing three-dimensional scanning, there is a problem that the image is twisted when constructing a three-dimensional image. In order to eliminate such a problem, it is also considered to arrange the rotation detecting means in the immediate vicinity of the ultrasonic transducer. However, especially in the ultrasonic probe in the body cavity, the outer diameter of the insertion portion is limited, and it is very difficult to provide a rotary encoder or the like at the tip of the probe. Further, if a rotary encoder is provided at the tip of the probe, a cable for transmitting the rotation information signal detected by the rotary encoder is additionally required, which increases the outer diameter of the probe sheath and leads to an increase in cost. The present invention has been made in view of these problems, and does not change the outer diameter dimension of the ultrasonic probe and does not require the addition of a dedicated signal line, and provides stable ultrasonic waves without rotation. The present invention relates to an ultrasonic diagnostic apparatus capable of obtaining an image.

[0007]

In order to solve the above-mentioned problems, an ultrasonic diagnostic apparatus of the present invention is an ultrasonic probe for mechanically rotating an ultrasonic transducer arranged in a probe sheath to perform a radial scan. In the ultrasonic diagnostic apparatus for forming an ultrasonic image by detecting the reflection echo of the ultrasonic pulse projected from the ultrasonic transducer, in a part in the circumferential direction of the probe sheath, the material of the probe sheath and Is provided with a dissimilar material portion having different acoustic impedance, and is provided with signal identifying means for identifying an ultrasonic echo signal reflected from the dissimilar material portion and an ultrasonic echo signal reflected from the probe sheath material. It is characterized in that an ultrasonic image writing start signal is generated based on the signal identified by the means.

[0008]

As described above, in the ultrasonic diagnostic apparatus of the present invention, the dissimilar material portion having a different acoustic impedance from the probe sheath material is provided in a part of the circumference of the probe sheath. It is detected that the signal level of the ultrasonic echo signal reflected by the probe sheath differs from the signal level of the ultrasonic echo signal reflected by the probe sheath, and based on this detection signal, the image drawing position signal (Z
Phase signal) is generated, and the ultrasonic image is configured based on the image drawing position signal, so that the physical rotation position of the ultrasonic wave emitting portion and the image position always match, It is possible to prevent the rotation of the image that occurs when the probe sheath bends.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the ultrasonic diagnostic apparatus of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration of a probe tip portion of an ultrasonic diagnostic apparatus according to a first embodiment of the present invention. An ultrasonic transducer 2 is arranged at the tip of a flexible shaft 1 connected to a drive unit (not shown) on the proximal side, and the flexible shaft 1 and the ultrasonic transducer 2 are connected to a probe sheath 3 made of a material such as polyethylene. It is inserted inside. The probe sheath 3 is filled with a fluid medium 4 such as water, and the fluid medium 4 functions as a lubricant and an ultrasonic transmission medium.

A dissimilar material portion 5 is arranged on a part of the circumference of the probe sheath 3. FIG. 2 is a cross-sectional view taken along the line AA of the probe tip portion shown in FIG. The dissimilar material part 5 is made of aluminum foil cut to a width of about 1 mm,
As shown in FIG. 2, the probe sheath 3 is sandwiched between double polyethylene tubes, heat-molded, and processed so as to be disposed within the thickness of the probe sheath 2.

FIG. 3 shows an image drawing position signal (hereinafter referred to as "Z
It is a block diagram which shows the structure of a detection circuit called "phase signal." The ultrasonic transducer 2 is connected to a preamplifier circuit 11 via a coaxial cable 10 extending in the flexible shaft 1. The output of the preamplifier circuit 11 is a general ultrasonic wave for forming and displaying an ultrasonic tomographic image. Signal processing circuit 1
2 and is further output to the display device 14 via the display control circuit 13. The output of the preamplifier circuit 11 is output via the buffer amplifier 15 to the voltage comparator 16
Is output to the positive input of. The output of the comparison voltage generation circuit 17 is connected to the negative input terminal of the voltage comparator 16, and the output of the voltage comparator 16 is supplied to the time gate circuit 18. On the other hand, the output from the gate signal generation circuit 19 that generates a gate signal for an arbitrary time determined by starting the trigger signal output each time the ultrasonic transducer 2 is driven is supplied to the time gate circuit 18. . The output of the time gate circuit 18 is connected to the A-phase synchronization circuit 20, and is configured to generate a Z-phase signal via the frequent occurrence prevention circuit 21 and guide the Z-phase signal to the display control circuit 13. There is.

FIG. 4 is a timing chart of each signal in the Z-phase signal detection circuit shown in FIG. Below, FIG.
The operation of this embodiment will be described with reference to FIGS. When the ultrasonic transducer 2 starts the radial scan,
As shown in the waveform of the echo signal in (a), the echo from the boundary surface of the probe sheath 3 returns after the large amplitude waveform at the time of driving. When the ultrasonic transducer 2 emits an ultrasonic beam in the direction of the dissimilar material portion 5, the normal probe sheath 3
Since the reflection intensity of the ultrasonic wave is larger than that of the signal returning from the boundary surface of, the echo level becomes larger in this portion. Setting the comparison voltage in the comparison voltage generation circuit 17
By setting the peak voltage of the echo reflected from the boundary surface of the sheath 3 and the peak voltage of the echo reflected from the dissimilar material portion 5, the ultrasonic transducer 2 moves the ultrasonic beam toward the dissimilar material portion 5. The voltage comparator 16 responds only when it radiates (FIG. 4 (b)). Actually, the voltage comparator 1 is affected by noise components such as a large amplitude waveform during driving.
Since 6 responds, the gate is applied by the time gate circuit 18. In this case, since the distance from the surface of the ultrasonic transducer 2 to the probe sheath 3 is always constant, the signal generation timing of the gate signal generation circuit 19 is changed from the generation of the trigger signal (FIG. 4 (d)) to that of the probe sheath. It is set according to the time required for the echo to reach from the vicinity of the boundary surface (FIG. 4C). In this way, the response signal from which the noise component has been removed by the time gate circuit 18 is output as the A-phase signal (FIG. 4E) from the rotary encoder (not shown) that detects the rotation of the motor.
256 pulses are output per one rotation of the rotary encoder), and the signals are input to the frequent occurrence prevention circuit 21 in synchronization with the A-phase synchronizing circuit 20. Since the dissimilar material portion 5 has a constant width, the response of the voltage comparator 16 is not limited to one (one sound ray segment) during one scan. The frequent occurrence prevention circuit 21 is configured to ignore the response of the voltage comparator 16 by a specific number of sound lines from the response of the first voltage comparator 16 by the counter control, and the output of the time gate circuit 18 outputs the frequent occurrence prevention circuit 21. By passing through, the Z-phase signal generated only once per one rotation of the ultrasonic transducer 2 is shaped (FIG. 4 (f)). This Z-phase signal is input to the display control circuit 13 and used here as a signal for drawing an ultrasonic tomographic image.

As described above, in the ultrasonic diagnostic apparatus of the present invention, since the physical position of the dissimilar material portion 5 and the drawing point of the ultrasonic tomographic image can be matched, the rotation transmission of the flexible shaft 1 is performed. It is possible to always obtain an ultrasonic tomographic image in a stable direction without being affected by the performance.

In the embodiment described above, a metal foil is used for the dissimilar material portion 5 so that the echo level reflected by the dissimilar material portion is higher than the echo level reflected by the boundary surface of the probe sheath. Conversely, the dissimilar material part 5 may be made of a material having a high ultrasonic wave permeability so that the echo level becomes small and the part where the echo level is decreased may be detected.

FIGS. 5 to 7 are views showing the configuration of the second embodiment of the present invention. Although the ultrasonic transducer 2 is configured to be radially scanned in the above-described first embodiment, this embodiment is configured to perform three-dimensional scanning by combining the radial scan and the linear scan.

As shown in FIG. 5, the flexible shaft 1 constituting the ultrasonic probe is connected to the rotating shaft of the DC motor 30. The rotation of the DC motor 30 is 1: 1
Is transmitted to the rotary encoder 32 via the gear 31 meshing with the gear ratio of, and the rotary encoder 32 outputs the rotational position signal of the ultrasonic transducer 2. These, D
The radial rotation unit 33 including the C motor 30, the gear 31, and the rotary encoder 32 is wholly connected to the linear drive unit 34. The linear drive unit 34 is fitted into a ball screw 35, and the rear end of the ball screw 35 is connected to the rotation shaft of a stepping motor 36.

FIG. 6 is a block diagram of a control circuit of the ultrasonic probe according to the second embodiment. 5 and 6 below.
The operation of this embodiment will be described with reference to FIG. When the radial control switch 40 is turned on to start the rotation of the DC motor 30, the rotary encoder 32 causes the DC motor 3 to rotate.
A rotation position signal (A-phase signal) of 256 pulses is output for each rotation of 0. The A-phase signal is supplied to the radial control circuit 44.
In the F / V converter (not shown), a so-called DC servo operation for controlling the supply voltage to the DC motor 30 is performed according to the frequency of the A-phase signal to obtain stable radial rotation.

On the other hand, when the linear control switch 42 is turned on, the linear control circuit 45 causes the stepping motor 36 to move.
Is supplied with a drive pulse, and the stepping motor 36 is driven to rotate. The rotation of the stepping motor 36 is transmitted to the ball screw 35 to move the radial rotating portion 33 connected to the linear driving member 34 in the linear direction. Actually, this linear movement is controlled so as to reciprocate within a specific section, but a detailed description thereof will be omitted here.

The output of the radial control switch 40 and the output of the linear control switch 41 are supplied to the input terminal of the AND gate 46, and the output of the AND gate 46 is input to the selector 43. A motor clock that serves as a reference for rotation of the stepping motor 36 is selected by the selector 43.
That is, the selector 43 has a rotary encoder 32.
To the A phase signal, and the clock generator 42 supplies a clock signal of a constant cycle. When the radial control switch 40 is turned on, the linear control switch 41 is turned on, and a three-dimensional scan is set, the output of the AND gate 46 becomes a low level, and the selector 43 supplies A to the rotary encoder 32. Since the phase signal is selected, the stepping motor 36 rotates in synchronization with the rotation in the radial direction. In other words, the movement speed in the linear direction also changes according to the change in the rotation speed in the radial direction, and as a result, a constant linear movement width is obtained for each rotation in the radial direction. Even if is changed, the slice interval of the ultrasonic tomographic image can be kept constant.

On the other hand, the radial control switch 40 is turned off.
Then, when only the linear control switch 41 is turned on, the output of the AND gate 46 becomes high level, the clock signal supplied from the clock generator 42 is selected by the selector 43, and the linear scan is performed at the optimum speed. Will be seen.

Thus, the radial control switch 40
, And the linear control switch 41 can be set completely independently. Therefore, the radial scan, the linear scan, and the three-dimensional scan can be individually realized with one ultrasonic probe. FIG. 7 shows an image of each scan. By disposing the dissimilar material portion 5 in the probe sheath of the ultrasonic probe configured as described above, even when a three-dimensional scan is performed, the ultrasonic image drawing position and the physical rotation position of the ultrasonic wave radiating portion are obtained. Can be matched with.

[0022]

As described above, according to the present invention, the ultrasonic transducer has a simple structure without changing the outer diameter of the ultrasonic probe and without adding a dedicated signal line. It is possible to obtain a Z-phase signal that faithfully reflects the physical rotational position of the ultrasonic wave and prevent the ultrasonic image from rotating. Further, by adopting the configuration as described in the second embodiment, radial scanning with one ultrasonic probe,
The linear scan and the three-dimensional scan can be realized independently, and the Z-phase signal reflecting the rotational position of the ultrasonic transducer can be obtained not only in the radial scan but also in the three-dimensional scan. it can.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a first exemplary embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of the ultrasonic probe shown in FIG.

FIG. 3 is a block diagram showing a configuration of a Z-phase signal detection circuit.

FIG. 4 is a waveform diagram of each signal in the Z-phase signal detection circuit.

FIG. 5 is a diagram showing a configuration of a second exemplary embodiment of the present invention.

FIG. 6 is a block diagram of a control circuit of an ultrasonic probe according to a second embodiment of the present invention.

FIG. 7 shows an image of each scan in the second embodiment of the present invention.

[Explanation of symbols]

 1 Flexible Shaft 2 Ultrasonic Transducer 3 Probe Sheath 4 Flow Medium 5 Different Material Section 10 Coaxial Cable 11 Preamplifier Circuit 12 Ultrasonic Signal Processing Circuit 13 Display Control Circuit 14 Display Device 16 Voltage Comparator 17 Comparison Voltage Generation Circuit 18 Time Gate Circuit 19 Gate signal generation circuit 20 A phase synchronization circuit 21 Multiple occurrence prevention circuit 30 DC motor 31 Gear 32 Rotary encoder 33 Radial rotating part 34 Linear drive member 35 Ball screw 36 Stepping motor 40 Radial control switch 41 Linear control switch 42 Clock generator 43 Selector 44 Radial control circuit 45 Linear control circuit 46 AND gate

Claims (1)

[Claims] 1. An ultrasonic probe for performing radial scan by mechanically rotating an ultrasonic transducer arranged in a probe sheath, and detecting a reflected echo of an ultrasonic pulse projected from the ultrasonic transducer. An ultrasonic diagnostic apparatus for forming an ultrasonic image by providing a different material portion having a different acoustic impedance from the material of the probe sheath at a part in the circumferential direction of the probe sheath, and the ultrasonic wave reflected from the different material portion. A signal discriminating means for discriminating the echo signal and the ultrasonic echo signal reflected from the probe sheath material is provided, and an ultrasonic image writing start signal is generated based on the signal discriminated by the signal discriminating means. An ultrasonic diagnostic apparatus characterized by being configured.