JPH07148167A - Ultrasonic diagnostic apparatus - Google Patents

Abstract

PURPOSE:To provide an ultrasonic tomogram with a high frame rate by reducing image producing time without reducing the large number of ultrasonic sound rays in such a manner that a multiplexer selects a plurality of oscillating elements or a plurality of groups of oscillating elements in order but in parallel to send and receive ultrasonic waves. CONSTITUTION:A multiplexer 2 selects a first and a second group of oscillating elements of an oscillator array 1 with the oscillating elements shifted one by one in the same direction, and when ultrasonic beams are shifted through a minute angle, transmission and reception of ultrasonic waves are carried out. Ultrasonic received signals in all angular directions of 0-360 deg. are supplied by the ultrasonic beams which are emitted by the groups 3a, 3b of oscillating elements, and undergo transformation of coordinate system and processing of interporation in a digital scan converter 9 so as to be displayed on a display unit 12 in a easy-to-see way. Consequently, an ultrasonic tomogram composed of a large number of sound rays may be supplied in a short time, and the quality and the frame rate of the image may be improved efficiently.

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 for transmitting and receiving ultrasonic waves to and from a living body to obtain an ultrasonic tomographic image in the living body.

[0002]

2. Description of the Related Art As an ultrasonic diagnostic apparatus, for example, various ultrasonic endoscopes have been proposed in which ultrasonic waves are transmitted and received from a mechanically rotating oscillator to obtain a tomographic image of the inside of the stomach wall and intestinal wall. ing. However, in such an ultrasonic endoscope, since the vibrator is rotated via the flexible shaft, there is a problem that rotation transmission is not stable and an output image flows or shakes.

To solve such a problem,
The applicant of the present invention, for example, in Japanese Patent Laid-Open No. 5-92002,
An array type transducer is incorporated at the tip of the probe to synthesize an ultrasonic image by the aperture synthesis method. In such an ultrasonic diagnostic apparatus, in order to obtain one image, ultrasonic waves are transmitted and received once for each of multidirectional or multiple vibrating elements at time intervals according to the observation field of view, and for example, 512 acoustic lines are transmitted. Data is obtained, coordinate conversion and interpolation processing are performed based on these sound ray data, and an ultrasonic tomographic image is output to the display.

[0004]

According to the ultrasonic diagnostic apparatus previously proposed by the applicant of the present invention, it is possible to obtain a stable ultrasonic tomographic image without causing image flow or shaking.
According to various experiments by the present inventor, it was found that there are points to be improved as described below. That is, in the ultrasonic diagnostic apparatus, one tomographic image is constructed by ultrasonically driving multi-directional or multiple vibrating elements at time intervals according to the observation field of view. In order to do so, the number of sound rays of ultrasonic waves forming an image is generally required to be 512 or more.

Further, in an ultrasonic diagnostic apparatus for a living body, the object to be observed constantly moves, so that the image forming time is short, that is, the number of image forming units per unit time, that is, the frame rate is required to be as large as possible. There is.

However, the number of sound rays and the frame rate are in a trade-off relationship with each other. If the number of sound rays is increased to improve the image quality, the frame rate becomes smaller, and if the frame rate is increased, There is a problem that the image quality must be sacrificed by reducing the number of sound rays.

The present invention has been made in view of the above problems, and it is possible to shorten the image construction time while keeping the number of ultrasonic ray lines large, and therefore, the ultrasonic wave having a good image quality and a large frame rate. An object of the present invention is to provide an ultrasonic diagnostic apparatus that is appropriately configured to obtain a tomographic image.

[0008]

To achieve the above object, according to the present invention, a transducer array in which a plurality of transducers are arranged, and a plurality of transducers for transmitting and receiving ultrasonic waves from the transducer array are provided. And a multiplexer for sequentially selecting the vibrating elements or plural vibrating element groups in parallel, and driving each vibrating element or vibrating element group in order to transmit ultrasonic waves from the selected plural vibrating element or vibrating element groups. A plurality of transmitting circuits, a plurality of receiving / combining means for processing reflected signals of ultrasonic waves received by the respective vibrating elements or vibrating element groups to obtain received signals in corresponding directions, and a plurality of these receiving / combining means. And a digital scan converter that creates one ultrasound image based on the received signal from the.

[0009]

In such a configuration, in the transducer array, a plurality of vibrating elements or a plurality of vibrating element groups for transmitting and receiving ultrasonic waves are sequentially selected by the multiplexer, and the selected plurality of vibrating elements or a plurality of vibrating elements are selected. Ultrasonic waves are transmitted from the element group by the respective transmission circuits. The echoes of these ultrasonic waves are received by each vibrating element or group of vibrating elements, and the reflected signal is processed by each receiving and combining means to obtain a receiving signal in a corresponding direction. Based on the above, one ultrasonic image is created in the digital scan converter.

As described above, a plurality of vibrating elements or a plurality of vibrating element groups are sequentially selected in parallel by the multiplexer to transmit and receive ultrasonic waves, thereby increasing the time for constructing one ultrasonic tomographic image. The number can be reduced, and the image quality and frame rate can be improved.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a first embodiment of the present invention. This embodiment uses a vibrator array 1 in which a large number of vibration elements are arranged in a circle.
The multiplexer 2 sequentially selects the first and second vibrating element groups 3a and 3b in parallel and transmits and receives ultrasonic waves. The first vibrating element group 3a selected by the multiplexer 2 is connected to the transmitting circuit 4a and the delay circuit 5a, respectively, and the second vibrating element group 3b is connected to the transmitting circuit 4b.
And the delay circuit 5b. Further, a transmitter 10 is connected to the transmission circuits 4a and 4b, and the transmitter 10
The transmission circuit 4a, 4b adjusts the timing so as to produce a desired ultrasonic beam on the basis of a transmission trigger from the first, second, and third vibrating element groups 3 through the multiplexer 2.
a, 3b are driven, and the ultrasonic beam 7
a and 7b are simultaneously transmitted. The first and second vibrating element groups 3a and 3b are selected so as to be opposite to each other in this embodiment so that ultrasonic waves do not interfere with each other. Equal in the example.

The echo of the ultrasonic beam 7a from the inside of the living body is the same as the first vibrating element group which has transmitted the ultrasonic beam 7a.
Of the first vibrating element group 3a which is received by the vibrating element group 3a and is supplied to the synthesizing circuit 6a via the multiplexer 2 and the delay circuit 5a.
The received signal in the direction corresponding to a is obtained. Similarly, the echo of the ultrasonic beam 7b from the living body is received by the second vibrating element group 3b that is the same as the vibrating element group that has transmitted the ultrasonic beam 7b, and the reflected signals thereof are received by the multiplexer 2 and the delay circuit. The signal is supplied to the synthesizing circuit 6b via 5b, and the received signal in the direction corresponding to the second vibrating element group 3b selected by the synthesizing process is obtained. The outputs of the synthesis circuits 6a and 6b are amplified to appropriate sizes by the receiving units 8a and 8b, respectively, and supplied to a digital scan converter (DSC) 9, where coordinate conversion and interpolation processing are performed, and then the display 12 is displayed. Display it. The multiplexer 2 and the digital scan converter 9
Timing of the operation of each unit such as is controlled by the control unit 11.

FIG. 2 is a diagram for explaining how the multiplexer 2 selects the first and second vibrating element groups 3a and 3b from the transducer array 1. In this example,
The multiplexer 2 selects the first and second vibrating element groups 3a and 3b while shifting the vibrating elements one by one in the same direction, and transmits and receives ultrasonic waves when the ultrasonic beams 7a and 7b deviate by a minute angle. The first and second
By the ultrasonic beam by the vibrating element groups 3a and 3b of
Ultrasonic wave reception signals in the entire circumference of 360 ° are obtained, and these reception signals are subjected to coordinate conversion and interpolation processing in the digital scan converter 9 and displayed on the display 12 in an easily viewable form.

As described above, in this embodiment, the multiplexer 2 sequentially selects the first and second vibrating element groups 3a and 3b from the transducer array 1 in which ultrasonic waves do not interfere with each other. Since the waves are transmitted and received, an ultrasonic tomographic image having a large number of sound rays (received signals) can be obtained in a short time. Therefore, the image quality and frame rate of the tomographic image can be effectively improved.

FIG. 3 shows a second embodiment of the present invention. In this embodiment, the applicant of the present invention discloses, for example, Japanese Patent Laid-Open No. 5-92.
The ultrasonic diagnostic apparatus using the aperture synthesis method proposed in Japanese Patent Laid-Open No. 002 aims to improve the frame rate of the ultrasonic diagnostic apparatus. The transducer array 1 in which a large number of vibrating elements are circularly arranged to the control unit 27 is used. Under control, the multiplexer 20 sequentially selects two vibrating elements separated from each other in parallel to transmit and receive ultrasonic waves.

One oscillating element selected by the multiplexer 20 is connected to the pulser 21a and the receiving / amplifying section 22a, respectively, and the other oscillating element is connected to the pulsar 21b and the receiving / amplifying section 22b, respectively. Also, pulsar 21
The oscillator 10 is connected to a and 21b, and a pulse of high amplitude is generated by the pulsars 21a and 21b based on the transmission trigger from the oscillator 10, and the two vibrating elements selected via the multiplexer 20 are selected. It is driven so that ultrasonic waves are simultaneously transmitted in the living body. The two vibrating elements that are selected in parallel by the multiplexer 20 are selected so as to be opposite to each other in this embodiment so that ultrasonic waves do not interfere with each other.

The echo from the inside of the living body of the ultrasonic wave transmitted from the one vibrating element selected by the multiplexer 20 is
The wave is received by the vibrating element, the reflected signal is amplified by the reception amplification section 22a through the multiplexer 20 to an appropriate size, and then converted into a digital signal by the A / D converter 23a.
The output of the A / D converter 23a is stored as wavefront data in the memory area of the wavefront memory 24a corresponding to the selected vibrating element under the control of the address control circuit 25a by the control unit 27. Similarly, the echo from the living body of the ultrasonic wave transmitted from the other vibrating element is received by the vibrating element, and the reflected signal is amplified to a proper size by the reception amplification section 22b via the multiplexer 20. Then, it is converted into a digital signal by the A / D converter 23b, and the output of the A / D converter 23b corresponds to the other selected vibrating element under the control of the address control circuit 25b by the control unit 27. It is stored as wavefront data in the memory area of the wavefront memory 24b.

The above operation is performed by transmitting and receiving ultrasonic waves while shifting two vibrating elements, which are selected in parallel by the multiplexer 20, in the same direction, whereby wavefront data in the entire circumference of 360 ° is stored in the wavefront memory 24a. , 24b in the corresponding memory areas. After that, the adder circuits 26a, 2
In 6b, the synthesizing process is performed based on the wavefront data obtained from each vibrating element, and those outputs are supplied to the digital scan converter 9 as sound ray data.

Here, the algorithm for synthesizing the wavefront data obtained from each vibration element is generally "Delay a
This is called "nd Sum", and in consideration of the delay time from transmission according to the spatial distance between the focus to be synthesized and each vibrating element, the wavefront data of each vibrating element is added to obtain the reflection intensity of the focus. It is a thing. Therefore, the wavefront memory 2
The read addresses of 4a and 24b are set to the control unit 2
7 through the address control circuit 25a to output a series of wavefront data corresponding to the focus from each wavefront memory 24a, 24b, and add the series of wavefront data by the adder circuits 26a, 26b, Obtain the sound ray data of the ultrasonic wave at the focal point. In this way, each addition circuit 26
Under the control of the control unit 27, the sound ray data obtained from a and 26b are subjected to coordinate conversion and interpolation processing by the digital scan converter 9 and displayed as a radial image on the display 12.

As described above, according to this embodiment, the multiplexer 20 sequentially selects two transducer elements from the transducer array 1 in which ultrasonic waves do not interfere with each other in parallel and transmits and receives ultrasonic waves. Since the ultrasonic wave tomographic image is obtained by processing the wavefront data of the vibrating element by the aperture synthesis method, the frame rate can be effectively improved.

It should be noted that the present invention is not limited to the above-described embodiments, but various modifications and changes can be made. For example, in the first embodiment, two vibrating element groups are selected and two ultrasonic beams are transmitted,
If the ultrasonic beams do not interfere with each other, three or more vibrating element groups may be selected in parallel so as to simultaneously generate three or more ultrasonic beams. By doing so, the frame rate can be further improved without degrading the image quality. Similarly, also in the second embodiment, three or more vibrating elements may be selected in parallel so that the ultrasonic waves simultaneously transmitted do not interfere with each other, and the frame rate can be further improved.

[0022]

As described above, according to the present invention, a plurality of vibrating elements or a plurality of vibrating element groups are sequentially selected in parallel by a multiplexer to transmit and receive ultrasonic waves. The image construction time can be shortened while increasing the number of sound rays, and therefore an ultrasonic tomographic image having a high image quality and a high frame rate can be obtained.

[Brief description of drawings]

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

FIG. 2 is a diagram for explaining how a vibrating element group is selected by the multiplexer shown in FIG.

FIG. 3 is a diagram showing a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 transducer array 2 multiplexers 3a, 3b vibrating element groups 4a, 4b transmission circuit 5a, 5b delay circuit 6a, 6b synthesis circuit 7a, 7b ultrasonic beam 8a, 8b receiver 9 digital scan converter 10 oscillator 11 controller 12 display Device 20 Multiplexer 21a, 21b Pulser 22a, 22b Reception amplification unit 23a, 23b A / D converter 24a, 24b Wavefront memory 25a, 25b Address control circuit 26a, 26b Adder circuit 27 Control unit

Claims (1)

[Claims] 1. A transducer array in which a plurality of transducers are arranged, and a plurality of transducers or a plurality of transducer groups for transmitting and receiving ultrasonic waves are sequentially selected in parallel from the transducer array. Multiplexer, and a plurality of transmission circuits that drive each vibrating element or vibrating element group to transmit ultrasonic waves from the selected vibrating element or vibrating element group, and each of these vibrating element or vibrating element groups. A plurality of receiving / combining means for processing reflected signals of received ultrasonic waves to obtain received signals in corresponding directions, and 1 based on the received signals from the plurality of receiving / combining means.
An ultrasonic diagnostic apparatus comprising: a digital scan converter that creates two ultrasonic images.