JPH0592002A - Intra-body cavity ultrasonic observation device - Google Patents

Abstract

PURPOSE:To provide the intra-body cavity ultrasonic observation device which obtains stable images by decreasing the number of signal lines so as to allow the easy incorporation of many array type vibrators into the limited space of an intra-body cavity probe and electronically scanning the many array type vibrators. CONSTITUTION:A vibrator body 10 which is disposed within the inserting front end of the intra-cavity probe and is lined up with the many vibrating elements 11-1 to 11-N and a multiplexer 12 for sequentially selecting these vibrating elements as well as a signal receiving and amplifying section 15 which is inputted with the outputs of the vibrating elements selected by this multiplexer via the signal lines 13 extended through the above-mentioned intra-cavity probe and amplifies these outputs are provided. An A/D converter 18 which converts the signals to digital signals, wave front memories 21-1 to 21-N which store the digital signals as wave front data in correspondence to the respective vibrating elements and wave front synthesizing circuits 23, 24 which execute addition processing in accordance with the outputs of the respective wave front memories are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic scanning type intracavity ultrasonic observation apparatus.

[0002]

2. Description of the Related Art Unlike an external ultrasonic observation device, an intracorporeal ultrasonic observation device observes organs such as the stomach and intestines because it is less affected by gas remaining in the body and less reflected by bones.
It has become widely used to diagnose.

As such an intracorporeal ultrasonic observation apparatus, a motor drive unit is provided at the hand, and the oscillator incorporated in the distal end portion through the flexible shaft is mechanically rotated by the motor drive unit and synchronized with the rotation. A so-called ultrasonic endoscope that transmits and receives ultrasonic waves to obtain images in the circumferential direction, and a convex ultrasonic wave that electronically scans by incorporating an array transducer at the tip There is something called an endoscope or an electronic linear ultrasonic endoscope.

[0004]

However, in the former ultrasonic endoscope in which the vibrator is mechanically rotated through the flexible shaft, the rotation transmission by the flexible shaft is not stable, There is a problem that image output and image fluctuations occur in the output image, and in the latter ultrasonic endoscope incorporating an array type transducer, there is a restriction on the number of signal lines that can be incorporated in the space of the probe in the body cavity. Therefore, there is a problem that the number of transducers is limited and an ultrasonic image with sufficient image quality cannot be obtained.

The present invention has been made by paying attention to such conventional problems, and an object thereof is to easily incorporate a multi-element array type vibrator into a limited space of a probe in a body cavity. An object of the present invention is to provide an intracorporeal ultrasonic observation apparatus appropriately configured to obtain a stable image by reducing the number of signal lines and electronically scanning a multi-element array type transducer.

[0006]

In order to achieve the above object, according to the present invention, a vibrator main body, which is arranged in the insertion tip portion of a probe in a body cavity and is formed by arranging a large number of vibration elements in an array, and the vibration elements are sequentially arranged. A multiplexer for selection, a reception amplification section for inputting and amplifying the output of the vibration element selected by the multiplexer through a signal line extending through the intracavity probe, and the signal is converted into a digital signal. An A / D converter, a wavefront memory that stores the digital signal as wavefront data corresponding to each vibrating element, and a wavefront synthesis circuit that performs addition processing based on the output of each wavefront memory are provided.

[0007]

In other words, according to the present invention, the vibrator main body having a large number of vibration elements and the multiplexer are arranged in the insertion tip portion of the probe in the body cavity, and while transmitting and receiving while sequentially selecting the vibration elements of the vibrator main body by the multiplexer. By repeating the above, the received signal obtained from each vibration element is taken out through the signal line, stored in the wavefront memory as wavefront data via the reception amplification section and the A / D converter, and wavefront synthesis is performed based on these wavefront data. In the circuit, addition processing is performed by the method of aperture synthesis to obtain the reflection intensity distribution. As described above, if the vibrating elements are sequentially selected by the multiplexer and the transmission / reception is performed in a time-division manner, the signal line of the vibrating element is basically one common line.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram for explaining the aperture synthesis method. In FIG. 1, a large number of vibrating elements 1-1, ..., 1-
The wavefront signals from the respective vibrating elements 1-i of the oscillator body 1 having i, ... Are stored in the wavefront memory 2, and the wavefront signals stored in the wavefront memory 2 are wavefront synthesized to transform the original spatial coordinates. The output image 3 thus obtained is obtained.

In FIG. 1, when an ultrasonic wave pulse is transmitted from the vibrating element 1-1, the ultrasonic wave signal is reflected by the reflectors 4a and 4b, and the wavefront memory 2 as a wavefront signal 5-1.
Stored in. Similarly, when an ultrasonic pulse is transmitted from the vibrating element 1-i, the reflected signal is stored in the wavefront memory 2 as the wavefront signal 5-i. These wavefront signals 5-1,
5-i are the respective vibrating elements 1-1, 1-i and the reflectors 4a, 4
Since the spatial positional relationship with b is different, the waveforms are different from each other.

Therefore, if the successive wavefront signals 5-i are combined in the wavefront memory 2 so as to adjust the delay or advance of the propagation time between a certain arbitrary spatial point and each of the vibrating elements 1-i, the conventional delay will occur. Similar to beam homing by the circuit,
It is possible to detect a reflection signal only in an arbitrary space. This is generally called "Dilay and Sum", and if the wavefronts to be wavefront-combined are combined for all the spaces, the original spatial coordinate-converted output image 3 is obtained, and the reflectors 4a, 4b are obtained.
You can see the distribution of.

Here, it should be noted that each vibration element 1
Even if the directional characteristic of -i alone is wide and sufficient lateral resolution cannot be obtained, the directional characteristic of the entire vibrating element group 1 becomes sharp by wavefront synthesis, and the lateral resolution is improved. From a different perspective, this is as sharp as when using a vibrating element with a large aperture, by detecting a wavefront signal while moving the vibrating element with a small aperture in a large space and combining them. Since directional characteristics are obtained, this is called aperture synthesis.

FIG. 2 shows an embodiment of the present invention. In this embodiment, the oscillator body 10 is composed of a large number of vibrating elements 11-1 to 11-N arranged on the same circumference, and is placed in the insertion tip of the intracavity probe. These vibrating elements 11-1 to 11-N are sequentially selected by the multiplexer 12 arranged in the insertion tip portion, and the selected vibrating elements are provided outside via the signal line 13 extending through the probe in the body cavity. It is connected to the transmission circuit 14 and the reception amplification section 15 to transmit ultrasonic waves in a time division manner.
Receive. The amplification factor of the reception amplification unit 15 is set by the STC control circuit 16 according to the elapsed time from transmission.
Controlled by the C voltage, the output of the reception amplification section 15 is supplied to the multiplexer 19 via the band pass filter (BPF) 17 and the A / D converter 18.

The multiplexer 19 is a multiplexer 1 for selecting an oscillating element by the switching control circuit 20.
The control is performed in synchronism with the A.D.
Resonator elements 11-1 to 11-converted into digital signals by
Wavefront memories 21-1 to 21-corresponding to N reception outputs.
Store in N. The writing address circuit 22 and the reading address circuit 23 respectively control the writing and reading of the wavefront data to and from the wavefront memories 21-1 to 21-N, and the read wavefront data is supplied to the adding circuit 24 and the log converting circuit 25. Then, it is supplied to the digital scan converter (DSC) 26 and displayed on the display 27. Note that S in the STC control circuit 16
The TC voltage is controlled in synchronization with the writing by the write address circuit 22, and the addition processing by the adding circuit 24 and D
The write processing in SC26 is performed by the read address circuit 2
Control is performed in synchronism with the reading by 3.

The operation of this embodiment will be described below. First, under the control of the switching control circuit 20, the multiplexers 12 and 19 are switched to select the oscillating element 11-1 and the wavefront memory 21-1 respectively. In that state, an impulse wave is generated from the transmission circuit 14, and the impulse wave is generated by the signal line 13 and the multiplexer 12.
To the vibrating element 11-1 via the
To radiate ultrasonic waves to the living body. The echo of the ultrasonic wave in the living tissue is received by the vibrating element 11-1 and converted into an electric signal (reflected signal), and the reflected signal is passed through the multiplexer 12 and the signal line 13 to the proper reception / amplification unit 15. After being amplified to a size, it is converted into a digital signal by the A / D converter 18 via the BPF 17, and this is converted into wavefront data in the wavefront memory 21-1 in time series based on the address from the write address circuit 22 via the multiplexer 19. To store.

Next, the switching control circuit 20 switches the multiplexers 12 and 19 to select the vibrating element 11-2 and the wavefront memory 21-2, respectively, and the vibrating element 11-2 similarly performs transmission / reception. The reflected signal is used as wavefront data in the wavefront memory 21-
Store in 2. The same operation is performed for other vibrating elements 11-3 to
11-N are sequentially performed, and the vibration elements 11-1 to 11-1
Wavefront memory 21-1 corresponding to each wavefront data in 1-N
To 21-N.

When the wavefront data from all the vibrating elements 11-1 to 11-N are obtained by repeating such processing, the wavefront data are described in FIG.
The addition circuit 24 performs addition processing by the method of aperture synthesis of "m" to reconstruct an image of the intensity distribution of the reflector in each space. Therefore, first, the read address circuit 23 controls the addresses so that the time axes of the wavefront memories 21-1 to 21-N become equal phase wavefronts, and the wavefront memories 21-1 to 21-
Read N wavefront data.

3A and 3B show address relationships for wavefront synthesis in the wavefront memories 21-1 to 21-N. FIG. 3A shows the direction of 60 degrees, FIG. 3B shows the direction of 120 degrees, and FIG.
The case where the reflection signals in the 00-degree direction are respectively combined is shown. 3A to 3C, the wavefront memories 21-1 to 21-1
In 21-N, the vibrating elements 11-1 to 11-11 are arranged from the top to the bottom.
~ N, and the direction from left to right corresponds to the distance.
Wavefront synthesis in the case of FIG. 3A is performed by adding the data of the equiphase wavefronts shown in the figure. Here, the equiphase wavefront is determined by the geometrical positional relationship between each vibrating element 11-i and the spatial point 30a or 30b to be reproduced, as shown in FIG. That is, each vibrating element 11-i
Since the propagation time from the space point to the spatial point is different, the memory address may be adjusted so as to correct this propagation time.

Further, when detecting the reflection signal in the direction of 60 degrees, the output of the vibrating element in the shaded portion of the vibrator main body 10 cannot be used. Therefore, as shown in FIG. The vibrating element output of is used. When applied to FIG. 3A, this means that about 1/4 of the memory is used to synthesize the signal in the direction of 60 degrees. Similarly, when synthesizing signals in the direction of 120 degrees as shown in FIG. 3B, the range of usage data in the memory is shifted and used,
Further, when the signals in the direction of 300 degrees are combined, the data in the memory range shown in FIG. 3C is used.

The equiphase wavefront for adding the above wavefront data is a kind of hyperbola which has a large curvature at a short distance portion and a curvature which becomes smaller as it gets further away. Since this wave field synthesis aims to perfectly focus on an arbitrary spatial point, it is possible to obtain the same effect as that of the dynamic focus in the conventional beam synthesis method, and it is possible to obtain an effect in the very close range or the far range. In the observation, the deterioration of the lateral resolution can be reduced.

As described above, the data of the equiphase wavefront read by the address from the read address circuit 23 is added by the adder circuit 24, and when the intensity of the reflected signal at a certain spatial point is obtained, the signal is log-converted. The circuit 25 detects and compresses and supplies it to the DSC 26.
At the same time, the coordinate system is converted so as to match the format of the display device 27, and at the same time, if necessary, interpolation between pixels is performed and output to the display device 27 to display an ultrasonic image.

In the above-described embodiment, the oscillator main body is formed by arranging a large number of vibrating elements on the same circumference. However, even when the oscillator main body is formed by a convex type or a linear array, it is necessary to adjust to it. If the addition processing is performed on the equal phase wavefront and the wavefront synthesis is performed, the reflection characteristic of the target space can be detected.

[0022]

As described above, according to the present invention, each vibrating element is selected in time division for transmission / reception,
The wavefront data obtained by this is stored in the memory, and the wavefront synthesis is performed based on the wavefront data to obtain the reflection distribution in a predetermined space, so that basically one signal line can be used. it can. Therefore, the outer diameter of the signal line up to the vibrator portion can be reduced, which facilitates incorporation into the probe in the body cavity. Moreover, since the number of vibrating elements can be set regardless of the number of signal lines, it is possible to easily increase the number of vibrating elements and improve the image quality. further,
When the vibrating elements are arranged on the same circumference, the ultrasonic beam is electronically rotated at a constant speed, so that there is no problem of image flow or shaking, and a stable image can be obtained.

[Brief description of drawings]

FIG. 1 is a diagram for explaining an aperture synthesis method.

FIG. 2 is a diagram showing an embodiment of the present invention.

FIG. 3 is a diagram for explaining an address relationship for wave field synthesis.

FIG. 4 is a diagram for explaining a geometrical relationship between each vibrating element and a space point.

[Explanation of symbols]

 10 vibrator main body 11-1 to 11-N vibrating element 12, 19 multiplexer 13 signal line 14 transmission circuit 15 reception amplification section 16 STC control circuit 17 band pass filter (BPF) 18 A / D converter 20 switching control circuit 21-1 21-N Wavefront memory 22 Write address circuit 23 Read address circuit 24 Adder circuit 25 Log conversion circuit 26 Digital scan converter (DSC) 27 Display

Claims (1)

[Claims] 1. A vibrator main body, which is arranged in the insertion tip portion of a probe in a body cavity and has a large number of vibrating elements arranged in an array, and a multiplexer for sequentially selecting the vibrating elements, and a vibrating element selected by the multiplexer. The receiving and amplifying unit for inputting and amplifying the output of the signal through the signal line extending through the probe in the body cavity, the A / D converter for converting the signal into a digital signal, and the digital signal to each vibrating element. An intracavity ultrasonic observation apparatus comprising: a wavefront memory correspondingly stored as wavefront data; and a wavefront synthesis circuit that performs addition processing based on the output of each wavefront memory.