JPH07265305A - Ultrasonic diagnostic apparatus - Google Patents

Abstract

PURPOSE:To prevent the lowering of a frame rate in such a case that the animation scanning of a plurality of cross sections and a dynamic focus method are combined by performing the changeover control of a focus position after ultrasonic beams are emitted to a region of the same depth from respective transducer groups. CONSTITUTION:The focus position of transmission beam to a first transducer group 2 is determined and a minute vibrator to be driven is selected by a first multiplexer 4 and a transmission trigger signal is applied to the first transducer group 2 from a transmission circuit 6 through the first multiplexer 4 to drive the selected minute vibrator and an ultrasonic echo is received. Thereafter, the transmission focus position of a second transducer group 3 is determined and a minute vibrator to be driven is selected and the transmission signal of the transmission circuit 6 is applied to the second transducer group 3 to transmit ultrasonic beam and an ultrasonic echo is received. When the scanning of the first and second transducer groups 2, 3 is completed, the image data of a scanned cross section is displayed on a monitor 11.

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, it is provided with a plurality of transducer groups having a plurality of transducers arranged in an array in accordance with a plurality of cross sections to be scanned, and an ultrasonic beam focusing device. The present invention relates to a dynamic focus type ultrasonic diagnostic apparatus that changes a position.

[0002]

2. Description of the Related Art As a beam scanning method in an ultrasonic diagnostic apparatus, an electronic scanning method is generally used. In this electronic scanning method, a plurality of micro-vibrators forming a probe are provided with different delay amounts, so that the ultrasonic beam has directivity.

In such an electronic scanning system, a so-called electronic focusing method for narrowing a beam at an arbitrary position becomes possible. In this electronic focusing method, for example, an ultrasonic wave reflected from a focus point in a living body is received by each micro-vibrator, and an appropriate delay time is given to each signal obtained by each micro-vibrator. , The phases of the signals from the focus points are matched and the signals are added. The focus setting at the time of transmission is also the same, and the transmission ultrasonic beam is narrowed down at a predetermined focus point by giving the same delay time as that of reception to the focus point for each micro-vibrator.

If the electronic focusing method as described above is used, a multi-step focusing method (transmission dynamic focusing method) for obtaining an image with good resolution over the entire region from a shallow portion to a deep portion of a living body is possible. The multi-stage focus method sets a plurality of focus points according to the depth of the living body, transmits and receives ultrasonic waves to each of these focus points, and stores the data obtained at each focus point in the memory in the DSC. Then, one scan line data is created.

Further, it has a plurality of transducer groups,
There is a probe that drives a transducer corresponding to each transducer group to scan a plurality of cross sections and simultaneously display a moving image. For example, a probe that scans two cross sections is called a biplane probe.

[0006]

When displaying a moving image by using the dynamic focus method as described above, if the display screen is divided into a predetermined number (n) according to the depth of the living body, the frame rate becomes 1. However, there is a problem in that the real-time property of the image is deteriorated due to the decrease to / n. For this reason,
A method is conceivable in which the next ultrasonic beam is transmitted immediately after the elapse of the time required to receive the ultrasonic echo signal corresponding to the depth of interest. With this method, the time for receiving the ultrasonic echo signal can be shortened, and therefore, the decrease in frame rate can be suppressed. However, if the reception time is not set sufficiently large, the residual echo due to the immediately preceding ultrasonic beam may affect the reception of the next ultrasonic beam, resulting in noise in the image.

When a moving image is displayed on a plurality of cross sections at the same time by using a biplane probe or the like, the frame rate is reduced as compared with the display of a single cross section. When the dynamic focus method is adopted for this biplane probe etc., the frame rate further decreases,
Real-time property is lost. An object of the present invention is to eliminate the influence of the residual echo due to the immediately preceding ultrasonic beam and reduce the decrease in the frame rate when the moving image scanning of a plurality of cross sections such as a biplane probe is combined with the dynamic focus method.

[0008]

An ultrasonic diagnostic apparatus according to the present invention comprises beam transmission control means and focus control means. The beam transmission control means alternately switches a plurality of transducer groups that emit ultrasonic beams. The focus control unit controls the switching of the focus position after the ultrasonic beam is radiated from the transducer group to the region of the same depth under the control of the beam transmission control unit.

[0009]

In the ultrasonic diagnostic apparatus according to the present invention, the ultrasonic beam is emitted by switching the transducer group provided according to a plurality of cross sections to be scanned by the beam transmission control means. After the ultrasonic beam is radiated from each transducer group to the region of the same depth, the focus control means controls the switching of the focus position. As a result, each transducer group can prevent the influence of the residual echo when receiving the ultrasonic beam scanning the same cross section. Further, even if the reception time is set to be short, there is no influence of the residual echo, so that it is possible to suppress the reduction of the frame rate.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An ultrasonic diagnostic apparatus to which an embodiment of the present invention is applied will be described with reference to the drawings. In the figure, as the probe 1, for example, a probe for body cavity as shown in FIG. 2 is used. The probe 1 includes a first transducer group 2 and a second transducer group 3 for scanning different cross sections. The first transducer group 2 and the second transducer group 3 are composed of, for example, a plurality of micro-vibrators arranged at intervals of 0.5 mm, and are connected to the first multiplexer 4 and the second multiplexer 5, respectively. The first multiplexer 4 and the second multiplexer 5 are
It is for performing electronic scanning. The first multiplexer 4 and the first transducer group 2 and the second multiplexer 5 and the second transducer group 3 are connected by a plurality of signal lines corresponding to the number of micro-vibrator included in each transducer group. A wave transmission circuit 6 and a wave reception circuit 7 are connected to the first multiplexer 4 and the second multiplexer 5. The first multiplexer 4 and the second multiplexer 5 are connected to the wave transmission circuit 6 and the wave reception circuit 7 by signal lines with a maximum simultaneous drive element number n (for example, 48).

The wave transmission circuit 6 is for giving a drive pulse delayed to converge the ultrasonic beam at each focus point to the first transducer group 2 and the second transducer 3. A wave transmission focus control unit 8 is connected to the wave transmission circuit 6. The wave transmission focus control unit 8 gives the wave transmission circuit 6 delay data for wave transmission according to the focus position.

The wave receiving circuit 7 includes a phase synthesizing circuit for phasing and adding reflected echoes, and a logarithmic amplification detection circuit for performing logarithmic amplification and detection processing for obtaining tomographic data. The receiving circuit 7 is connected to the receiving focus control section 9.
The reception focus control unit 9 gives delay data for reception to the reception circuit 7. The wave receiving circuit 7 is connected to the DSC 10. The DSC 10 has an image memory and stores image data input at the transmission timing of an ultrasonic beam.
Convert to standard television signal. Also DSC1
In 0, data for the number of focus points is stored in correspondence with the focus area, and data for the number of focus points is combined in each focus area to obtain one sound ray data. A monitor 11 is connected to the DSC 10.

An overall control circuit 12 is connected to the first multiplexer 4, the second multiplexer 5, the wave transmission focus control unit 8, the wave transmission circuit 6, the wave reception focus control unit 9 and the DSC 10. The overall control circuit 12 includes a CPU,
It is composed of a microcomputer including a ROM and a RAM. A keyboard 13 is connected to the overall control circuit 12. The keyboard 13 is provided with various keys such as a step number key for setting the number of focus points, a size key for setting a display size (magnification), and a cursor key for setting a display position. The overall control circuit 12 controls the entire apparatus, determines a display area from the display size and display position, sets the focus position by the number of steps and the display area, and generates focus address data and aperture data.

In the probe 1, for example, as shown in FIG. 3, the first transducer group 2 can be constituted by a sector scanning method and the second transducer group 3 can be constituted by a linear scanning method. At this time, the region in the depth direction in the subject is defined as the proximity region N,
When divided into an intermediate region M and a distant region F, each region N, M,
One frame of the first tomographic image 14 and the second tomographic image 15 is formed based on the individual echo signals obtained from within F.

The operation of the present invention will be described with reference to the flowchart shown in FIG. In step S1, the focus position of the transmitted beam with respect to the first transducer group 2 is determined, and which of the micro-vibrator of the first transducer group 2 is to be driven is selected by the first multiplexer 4. In step S2, a wave transmission trigger signal is supplied from the wave transmission circuit 6 to the first transducer group 2 via the first multiplexer 4 to drive the micro-vibrator selected in step S1. In step S3, ultrasonic echoes are received by the first transducer group 2. In step S4, it is determined whether or not the reception time by the first transducer group 2 has reached the time corresponding to the transmission focus position of the first transducer group 2 determined in step S1. If the corresponding reception time has not elapsed here, the process proceeds to step S3. When the reception time corresponding to the wave transmission focus position of the first transducer group 2 has elapsed, the process proceeds to step S5.

In step S5, the transmission focus position of the second transducer group 3 is determined, and the micro-vibrator to be driven is selected. In step S6, the transmission signal from the transmission circuit 6 is given to the second transducer group 3, and the ultrasonic beam is transmitted by the second transducer group 3. In step S7, ultrasonic echoes are received by the second transducer group 3. In step S8, it is determined whether or not the reception time by the second transducer group 3 has reached the time corresponding to the transmission focus position of the second transducer group 3 determined in step S5. If the corresponding reception time is not reached here, the process proceeds to step S7. When it is determined in step S8 that the reception time of the second transducer group 3 has reached the time corresponding to the wave transmission focus position, the process proceeds to step S9. In step S9, it is determined whether the scanning of one cross section of the first transducer group 2 and the second transducer group 3 is completed. When it is determined in step S9 that the scanning is not completed, the process proceeds to step S1. If it is determined in step S9 that the scanning is completed, step S
Go to 10. In step S10, the image data of the scanning cross sections of the first transducer group 2 and the second transducer group 3 stored in the frame memory of the DSC 10 is displayed on the monitor 11.

The wave-transmitting signals that the wave-transmitting circuit 6 gives to the first transducer group 2 and the second transducer group 3 are, for example, a trigger signal group as shown in FIG. A transmission trigger signal (1-1 _N ) is given from the wave transmission circuit 6 to the transducer that transmits the ultrasonic beam to the shallow portion (N) of the first transducer group 2 via the first multiplexer 4. To be Transducer for transmitting an ultrasonic beam to the shallow portion (N) of the second transducer group 3 immediately after the time when the first transducer group 2 is considered to receive the ultrasonic echo corresponding to the shallow portion (N). From the transmission circuit 6,
Transmission trigger signal 2-1 via the second multiplexer 5
Give _N. The second transducer group 3 is step S
When the ultrasonic echo for the shallow portion (N) transmitted in 6 is completely received, the transmission circuit 6 is transmitted to the micro-vibrator that transmits the intermediate portion (M) in the first transducer group 2. From the first multiplexer 4 to the transmission trigger signal 1-1 _M. Immediately after the lapse of time when the first transducer group 2 finishes receiving the ultrasonic echo of the middle portion (M), a micro-vibrator for transmitting an ultrasonic beam to the middle portion (M) of the second transducer group 3, A transmission trigger signal 2-1 from the transmission circuit 6 via the second multiplexer 5.
Give _M. The second transducer group 3 is the middle part (M)
Immediately after the lapse of the time when the ultrasonic echo corresponding to is passed, the wave is transmitted from the wave transmission circuit 6 through the first multiplexer 4 to the micro-vibrator which transmits to the far part (F) of the first transducer group 2. Give the trigger signal 1-1 _F. Immediately after a lapse of time when the first transducer group 2 finishes receiving the ultrasonic echo corresponding to the far portion (F), a minute ultrasonic wave is transmitted to the far portion (F) of the second transducer group 3. A wave transmission trigger signal 2-1 _F is given to the oscillator from the wave transmission circuit 6 via the second multiplexer 5.

The transmission trigger signal 1-1 _N of the transmission circuit 6,
The echo signals received by the first transducer group 2 corresponding to 1-1 _M and 1-1 _F are stored in the frame memory in the DSC 10, and one of the first tomographic images 14 in FIG.
It becomes a scanned image of a book. Similarly, the second corresponding to the transmission trigger signals 2-1 _N , 2-1 _M and 2-1 _F of the transmission circuit 6
The ultrasonic echo signal received by the transducer group 3 is D
It is stored in the frame memory of the SC 10 and becomes one scan image of the second tomographic image 15 of FIG.

When the scanning of the transducer groups 2 and 3 is completed, the image data stored in the frame memory of the DSC 10 is displayed on the monitor 11 and the tomographic images 14 and 15 are displayed.
Is displayed. In the present example, the number of beams of the first transducer group 2 and the number of beams of the second transducer group 3 are shown to be the same, but the present invention can be applied even when the number of beams is not the same.

According to the present invention, when a plurality of cross-sections are scanned by using the dynamic focus method for changing the focus position of the ultrasonic beam, the reception time is set to be short according to the depth region to be scanned. However, there is no influence of noise due to the residual echo, and the entire image forming time can be shortened. Therefore, there is no influence of the residual echo, and it is possible to suppress the reduction of the frame rate as a whole.

[Other Embodiments] Two or more transducer groups can be provided, and the number of focus stages is not limited to three.

[0022]

The ultrasonic diagnostic apparatus according to the present invention can shorten the image construction time by varying the reception time according to the scanning depth of the dynamic focus system, and the image due to the residual echo can be obtained even if the reception time is short. Signal noise can be prevented.

[Brief description of drawings]

FIG. 1 is a control block diagram of an ultrasonic diagnostic apparatus in which an embodiment of the present invention is adopted.

FIG. 2 is a schematic explanatory view of a probe.

FIG. 3 is an explanatory diagram of a scanning section.

FIG. 4 is a control flowchart of the embodiment.

FIG. 5 is a time chart of a transmission trigger signal.

[Explanation of symbols]

 1 Probe 2 1st Transducer Group 3 2nd Transducer Group 4 1st Multiplexer 5 2nd Multiplexer 6 Transmitting Circuit 7 Receiving Circuit 8 Transmitting Focus Control Circuit 9 Receiving Focus Control Circuit 10 DSC 11 Monitor 12 Overall Control Circuit 13 Keyboard

Claims (1)

[Claims] 1. A dynamic focus type ultrasonic diagnostic apparatus comprising a plurality of transducer groups having a plurality of transducers arranged in an array according to a plurality of cross sections to be scanned, and changing a focus position of an ultrasonic beam. A beam transmission control unit that alternately switches the plurality of transducers that emit ultrasonic beams; and a focus position after the ultrasonic beam is emitted from the transducers to the site of the same depth under the control of the beam transmission control unit. An ultrasonic diagnostic apparatus, comprising: