JP3444546B2 - Ultrasound diagnostic equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic diagnostic apparatus for transmitting / receiving ultrasonic waves to / from a living body to obtain an ultrasonic tomographic image in the living body. . 2. Description of the Related Art As an ultrasonic diagnostic apparatus, for example, there is an ultrasonic endoscope which transmits and receives ultrasonic waves from a mechanically rotating vibrator and obtains in-vivo tomographic images of a stomach wall and an intestinal wall. Various proposals have been made. However, in such an ultrasonic endoscope, since the vibrator is rotated via the flexible shaft, the rotation transmission is not stable, and there is a problem that an output image flows or shakes. In order to solve such a problem,
The present applicant has disclosed in, for example, JP-A-5-92002,
An array type transducer is incorporated at the probe tip, and an ultrasonic image is synthesized by an 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 the multi-directional or many vibrating elements at time intervals according to the observation field of view, for example, 512 sound rays. Data is obtained, coordinate conversion, interpolation processing, and the like are performed based on the sound ray data, and an ultrasonic tomographic image is output to a display. According to the ultrasonic diagnostic apparatus previously proposed by the present applicant, it is possible to obtain a stable ultrasonic tomographic image in which image flow or shaking does not occur. ,
According to various experiments by the present inventors, it has been found that there are points to be improved as described below. That is, in such an ultrasonic diagnostic apparatus, one tomographic image is constructed by performing ultrasonic driving on multi-directional or many vibrating elements at time intervals according to the observation field of view. Here, the image quality of the tomographic image is improved. In order to achieve this, 512 or more ultrasonic rays are generally required to form an image. Further, in an ultrasonic diagnostic apparatus for a living body, since an object to be observed constantly moves, it is necessary to shorten an image forming time, in other words, to increase the number of image forming per unit time, that is, the frame rate as much 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 is reduced. There is a problem that image quality must be sacrificed by reducing the number of sound rays. SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is possible to shorten an image construction time while keeping the number of sound rays of an ultrasonic wave large, so that an ultrasonic wave having a good image quality and a large frame rate can be obtained. It is an object of the present invention to provide an ultrasonic diagnostic apparatus appropriately configured to obtain a tomographic image. According to a first aspect of the present invention, there is provided an ultrasonic diagnostic apparatus comprising: a plurality of vibrating elements arranged in a circle and capable of generating ultrasonic waves in a radial direction; And a multiplexer capable of selecting a plurality of vibration elements or a plurality of vibration element groups in parallel from among the plurality of vibration elements, and transmitting an ultrasonic beam from the selected plurality of vibration elements or the vibration element groups. For this purpose, a plurality of transmitting circuits for driving each of the vibrating elements or the vibrating element groups, and processing of the reflected signals of the ultrasonic beams received by the respective vibrating elements or the vibrating element groups, and receiving signals in the corresponding directions, respectively. A plurality of receiving / synthesizing means for obtaining the ultrasonic beams in opposite radial directions which do not interfere with each other by controlling the multiplexer to select the plurality of vibrating elements or the plurality of vibrating element groups. Control means for controlling the multiplexer so as to generate the plurality of vibrating elements or the plurality of vibrating element groups sequentially in a predetermined direction while generating the signals in parallel, and receiving signals from the plurality of receiving / synthesizing means. And a digital scan converter that creates one ultrasonic image based on the According to the first aspect of the present invention, the vibrator array includes:
Under the control of the control means, the plurality of vibrating elements or the plurality of vibrating element groups are selected in parallel by the multiplexer, and the plurality of vibrating elements or the plurality of vibrating element groups are sequentially selected by the multiplexer in a predetermined direction. While being moved, a plurality of combined ultrasonic beams are transmitted from the selected plurality of vibrating elements or the plurality of vibrating element groups in parallel in the radial directions that do not interfere with each other by the respective transmitting circuits. The echoes of these ultrasonic beams are received by each vibrating element or vibrating element group selected in parallel by the multiplexer, and the reflected signals are processed by each receiving / synthesizing means to obtain received signals in the corresponding directions. Then, one ultrasonic image is created in the digital scan converter based on the reception signals from these reception synthesis means. As described above, the plurality of vibrating elements or the plurality of vibrating element groups in the vibrator array are selected in parallel by the multiplexer under the control of the control means, and the plurality of vibrating elements or the plurality of vibrating elements by the multiplexer are selected. In order to construct one ultrasonic tomographic image by transmitting and receiving ultrasonic waves that do not interfere with each other in a plurality of selected vibration elements or a plurality of vibration element groups while sequentially moving the group selection in a predetermined direction. Can be reduced, and the image quality and the frame rate can be improved. As described above, a plurality of vibrating elements or a plurality of vibrating element groups in the vibrator array are selected in parallel by the multiplexer under the control of the control means, and the plurality of vibrating elements or the plurality of vibrating elements by the multiplexer are selected. While sequentially moving the selection of the vibrating element group in a predetermined direction, transmitting and receiving ultrasonic waves in opposite radial directions that do not interfere with each other in the plurality of selected vibrating elements or the plurality of vibrating element groups, The time for constructing an ultrasonic tomographic image can be reduced, and the image quality and the frame rate can be improved. Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a first embodiment of the present invention. In this embodiment, a vibrator array 1 in which a number of vibrating elements are arranged in a circle is used.
The first and second vibrating element groups 3a and 3b are sequentially selected in parallel by the multiplexer 2 to transmit and receive 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. A transmitter 10 is connected to the transmitting circuits 4a and 4b.
The transmission circuits 4a and 4b adjust the timing so as to form a desired ultrasonic beam based on the transmission trigger from the first and second vibrating element groups 3 via the multiplexer 2.
a, 3b, thereby driving the ultrasonic beam 7 into the living body.
a and 7b are transmitted simultaneously. 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 interference does not occur, and the number of elements in each group is determined in this embodiment. In the example, they are equal. The echo of the ultrasonic beam 7a from within the living body is the same as the first vibration element group that transmitted the ultrasonic beam 7a.
And the reflected signals are supplied to the synthesizing circuit 6a via the multiplexer 2 and the delay circuit 5a, where they are synthesized and selected.
A received signal in a direction corresponding to a is obtained. Similarly, the echo of the ultrasonic beam 7b from the inside of the living body is received by the second vibrating element group 3b that is the same as the vibrating element group that transmitted the ultrasonic beam 7b, and the reflected signals are transmitted to the multiplexer 2 and the delay circuit. The signal is supplied to the synthesizing circuit 6b via 5b, where it is subjected to synthesizing processing to obtain a received signal in the direction corresponding to the selected second vibrating element group 3b. The outputs of the synthesizing circuits 6a and 6b are amplified to an appropriate size by the receiving units 8a and 8b, respectively, and supplied to a digital scan converter (DSC) 9, where they are subjected to coordinate conversion and interpolation processing and displayed on the display unit 12. Display. Note that the multiplexer 2, the digital scan converter 9
The operation of each unit such as is controlled by the control unit 11 in timing. FIG. 2 is a diagram for explaining how the multiplexer 2 selects the first and second vibrating element groups 3a and 3b from the vibrator array 1. As shown in FIG. In this example,
The first and second vibrating element groups 3a and 3b are selected by the multiplexer 2 while shifting the vibrating elements one by one in the same direction. When the ultrasonic beams 7a and 7b are shifted by a small angle, the transmission and reception of ultrasonic waves are performed. And the first and second
By the ultrasonic beam by the vibrating element groups 3a and 3b,
Ultrasonic reception signals over 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 manner. As described above, in this embodiment, the first and second vibrating element groups 3a and 3b in which the ultrasonic waves do not interfere with each other from the vibrator array 1 are sequentially selected in parallel by the multiplexer 2 and the ultrasonic waves are transmitted. Since transmission and reception are performed, an ultrasonic tomographic image including 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. This embodiment is described in, for example,
The ultrasonic diagnostic apparatus using the aperture synthesis method proposed in Japanese Patent Application Publication No. 002-002 discloses a basic principle of improving the frame rate of the ultrasonic diagnostic apparatus. Under the control, two transducers separated from each other are sequentially selected in parallel by the multiplexer 20 to transmit and receive ultrasonic waves. One vibrating element selected by the multiplexer 20 is connected to the pulser 21a and the receiving amplifier 22a, respectively, and the other vibrating element is connected to the pulser 21b and the receiving amplifier 22b, respectively. Pulsa 21
The oscillator 10 is connected to a and 21b. Based on a transmission trigger from the oscillator 10, high-amplitude pulses are generated by the pulsars 21a and 21b. Drive, thereby simultaneously transmitting ultrasonic waves into the living body. In this embodiment, the two vibrating elements selected in parallel by the multiplexer 20 are selected so as to be opposite to each other so that no ultrasonic interference occurs. The echo from the living body of the ultrasonic wave transmitted from one of the vibrating elements selected by the multiplexer 20 is:
The signal is received by the vibrating element, and the reflected signal is amplified to an appropriate size by the reception amplifier 22a through the multiplexer 20, and then converted to 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 vibration element under the control of the address control circuit 25a by the control unit 27. Similarly, the echo from the inside of 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 an appropriate size by the receiving amplifier 22b via the multiplexer 20. Thereafter, the signal 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 vibration 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 selected in parallel by the multiplexer 20 in the same direction, thereby storing the wavefront data over the entire 360 ° circumference in the wavefront memory 24a. , 24b in the corresponding memory areas. Thereafter, the adders 26a, 2
In step 6b, a synthesizing process is performed based on the wavefront data obtained from each of the vibrating elements, and the output is supplied to the digital scan converter 9 as sound ray data. Here, an algorithm for synthesizing the wavefront data obtained from each of the vibrating elements is generally called “Delay a
nd Sum ”, taking into account the delay time from the transmission according to the spatial distance between the focal point to be combined and each vibrating element, adding the wavefront data of each vibrating element to obtain the reflection intensity of the focal point Things. Therefore, the wavefront memory 2
4a and 24b are read from the control unit 2
7 through the address control circuit 25a to output a series of wavefront data corresponding to the focal point from each of the wavefront memories 24a and 24b, and add the series of wavefront data by the addition circuits 26a and 26b. Obtain ultrasonic ray data at the focal point. Thus, each of the adding circuits 26
The sound ray data obtained from a and 26b is subjected to coordinate conversion and interpolation processing by the digital scan converter 9 under the control of the control unit 27, and is displayed on the display 12 as a radial image. As described above, according to this embodiment, the multiplexer 20 sequentially selects, in parallel, two vibrating elements from which ultrasonic waves do not interfere with each other from the vibrator array 1 to transmit and receive ultrasonic waves. Since the wavefront data of the vibrating element is processed by the aperture synthesis method to obtain an ultrasonic tomographic image, the frame rate can be effectively improved. It should be noted that the present invention is not limited to the above-described embodiment, and various modifications or changes are possible. For example, in the first embodiment, two vibration element groups are selected to transmit two ultrasonic beams,
If the ultrasonic beams do not interfere with each other, three or more vibration element groups may be selected in parallel so that three or more ultrasonic beams are generated at the same time. In this way, the frame rate can be further improved without lowering the image quality. Similarly, in the second embodiment, it is also possible to select three or more vibrating elements in parallel so that the ultrasonic waves transmitted simultaneously do not interfere with each other, thereby further improving the frame rate. 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 the multiplexer to transmit and receive ultrasonic waves in mutually opposite radial directions which do not interfere with each other. Since the waves are formed, it is possible to shorten the image formation time while keeping the number of sound rays of the ultrasonic wave large, and thus it is possible to obtain an ultrasonic tomographic image having good image quality and a high frame rate.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing a first embodiment of the present invention. FIG. 2 is a diagram for explaining how a multiplexer shown in FIG. 1 selects a vibrating element group. FIG. 3 is a diagram showing a second embodiment of the present invention. [Description of Signs] 1 Transducer array 2 Multiplexers 3a, 3b Vibrating element groups 4a, 4b Transmission circuits 5a, 5b Delay circuits 6a, 6b Synthesis circuits 7a, 7b Ultrasonic beams 8a, 8b Receiving unit 9 Digital scan converter 10 Transmitter 11 Control Unit 12 Display 20 Multiplexers 21a, 21b Pulsers 22a, 22b Reception Amplification Units 23a, 23b A / D Converters 24a, 24b Wavefront Memory 25a, 25b Address Control Circuits 26a, 26b Addition Circuit 27 Control Unit

Claims (1)

(57) [Claims] [Claim 1] A plurality of vibrating elements are arranged in a circle and radially arranged.
A vibrator array capable of generating ultrasonic waves, and a plurality of vibrating elements or a plurality of vibrating elements among the plurality of vibrating elements.
Multiplexer capable of selecting a number of vibrating element groups in parallel
And ultrasonic waves from a plurality of selected vibrating elements or a group of vibrating elements.
Each vibrating element or vibrating element to transmit the beam
A plurality of transmission circuits for driving the groups, and ultrasonic waves received by each of these vibrating elements or vibrating element groups
The reflected signals of the beam are processed and received in the corresponding directions.
A plurality of receiving synthesizing means for obtaining a signal signal, the plurality of transducer elements also controls the multiplexer
Are mutually isolated by selecting the plurality of vibrating element groups.
Generates ultrasonic beams in parallel in opposite radial directions without interference
And the plurality of vibrating elements or the plurality of vibrating elements.
The selection of the moving element group is sequentially moved in a predetermined direction.
Control means for controlling a multiplexer, and one control means based on reception signals from the plurality of reception synthesis means.
Digital Scan Converter for Creating Ultrasound Images
An ultrasonic diagnostic apparatus comprising: