JPS5861739A - Ultrasonic diagnostic apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ultrasonic diagnostic apparatus that obtains a tomographic image of a subject by ultrasonic scanning, and particularly relates to an ultrasonic diagnostic apparatus that synchronizes unit scanning by ultrasonic waves with an electrocardiographic waveform of a subject. O An ultrasonic diagnostic apparatus obtains a tomographic image of a subject using ultrasonic waves, and this tomographic image is displayed on a display.

FIG. 1 is a diagram showing an example of a tomographic image displayed on a display. The figure shows the lid display screen.

Point a in the tomographic image shown in the figure corresponds to the position of the probe that is in contact with the subject. This probe transmits and receives ultrasonic waves to obtain tomographic information of one beam, and this beam is scanned in a fan shape to obtain a tomographic image as shown in the figure.

However, in order to enable the measurer to continuously view the tomographic images on the display screen without flickering, it is necessary to display information on new tomographic images at a rate of usually 30 frames/second. On the other hand, it takes about 300u to transmit and receive one beam of ultrasound.
It takes about 100 s of time. Therefore, due to the above-mentioned conditions, the scanning interval is limited, and the displayed tomographic image cannot be said to have sufficient resolution for the operator to perform accurate observation.

In addition, the scanning timing of the display device is asynchronous with the ultrasonic transmission and reception timing of the measuring device for obtaining tomographic information (i+). It also had the disadvantage that it was not possible to obtain the fault r°C.

The purpose of the present invention is to display the entire tomographic image with clearer and higher resolution in order to eliminate the above-mentioned drawbacks of the conventional technology. The aim is to provide a full range of ultrasonic diagnostic equipment that can more precisely display (-) the repetitive movements of tomographic images.

The ultrasonic diagnostic apparatus of the present invention achieves the above objective f.

Rhinoceros In an ultrasound diagnostic device that obtains a tomographic image of a subject by transmitting and receiving ultrasonic waves, there is an electrocardiograph that extracts the entire electrocardiogram waveform from the subject, and an ultrasound system that extracts the entire electrocardiogram waveform from the electrocardiograph. a transmission timing generation circuit that determines the signal transmission timing;
An ultrasonic signal is transmitted in synchronization with a transmission timing signal from the transmission timing generation circuit.

It is characterized in that it has a control unit that extracts a received signal corresponding to the transmitted signal, and transmits and receives the ultrasound signal in synchronization with the electrocardiographic waveform of the subject.

That is, by focusing on the fact that the electrocardiogram waveform and the movement of the heart are synchronized, unit scans are performed at the same phase of the electrocardiogram waveform to obtain tomographic images of the same state, and the scanning direction of the unit scans at the same phase is determined. The aim is to obtain a clearer tomographic image by superimposing tomographic information obtained by slightly shifting the tomographic information. 2nd below
The present invention will be fully described in detail with reference to FIGS.

FIG. 2 is a scanning time chart 1 for performing ultrasonic scanning in synchronization with an electrocardiogram waveform, and FIG. 3 is a diagram showing the principle of an ultrasonic beam emitted from a probe. As shown in FIG. 2, the start signal 5TA11. is synchronized with the phase of the electrocardiogram waveform and has a constant period. R, T to this start signal ST.
The unit scan timing signal 5CNN is determined based on .

In the figure, a 5CAN signal is generated that causes seven unit scans to be performed within one cycle of the electrocardiographic waveform, but in reality, approximately 100 unit scans are performed. For example, as shown in FIG. 2, all scanning signals 5CAN are generated in synchronization with the fall of STA, Ft, and T signals S1.

A unit scan is performed during the period when the 8CAN signal is falling. Similarly, 5TAR, T signal S2. By generating the SCΔN signal in synchronization with the falling edge of Sa, each unit scan is performed at the same phase of the electrocardiogram waveform (in Fig. 2, each scan is performed in one period)
times) can be performed. Further, as described below, the scanning direction of the unit scan is shifted by a minute angle for each cycle of the electrocardiographic waveform. That is, S T IVI(,i,”・
The unit run f′f is performed first from the falling edge of No. 16.
: Take this as an example! :, S'l'A11. 'r times signal IIC synchronization t, 7'c SC, A, N signals are transmitted and received one after another. Next 5TAI (, 5cAN from T signal S2
The unit positioning is performed from the time jl when the -+= signal first falls, as shown in Figure 3.
The first unit scan performed from the TA RT signal is at time t.
The beam in the same direction as the unit scan performed by l
.

fired. By repeating the same operations as 'q and '゛, and superimposing the scan information performed from it time t, tl, t in the example shown in Fig. 3, the scan ``iv'' in the degree scan is This means that a tomographic image three times as high as that of the previous one can be obtained.

Figure 4 is a principle block diagram showing an embodiment of the ultrasonic diagnostic apparatus 7) which can perform all the ultrasonic scanning operations described above.

In the same figure, 2 I, 1 electrocardiograph, 3 is a differential circuit, 4 (is a comparator, 5rr:F, one-shot circuit, 6.13 is a counter, 7° 14.17) is a code converter, 8, 9 are a code converter. Delay circuit, 10j-l clock source, 11.12 is frequency divider, 151d addition circuit.

16 is a display counter, 18 is a receiving circuit 22, an A/D converter, 23 memories, 24 is a display control unit, 25 is a CR,
26 is a probe, and 27 is a multiplexer. In this embodiment, the probe 26 is an electronic sector scanning type probe using an array of transducer elements (transducers). The delay circuit 8 sets an appropriate delay time for each transducer, causes the ultrasonic beam to scan in a fan shape, and performs each unit scan. The delay circuit 9 shifts the scanning direction of the electrocardiogram waveform by a minute angle for each cycle, giving a constant deflection to each beam in a unit scan. A/I creates a timing clock that samples scanning information and writes it into memory using a high-frequency clock.
) converter 22. Memory 23. A clock is supplied to the multiplexer 27. The output of the frequency divider 11 is further divided by a frequency divider 12, and the output clock of the frequency divider 12 is supplied to the delay circuit 8 as the ultrasound beam emission timing clock. The output clock of the divider 12 is also input to the counter 3, and the output of the counter 13 is further connected to the code converter 14. Code converter 1
4 gives a delay time to each delay circuit 8 in order to determine the direction of the scanning beam corresponding to the count value of the counter 3. On the other hand, the output electrocardiogram waveform of the electrocardiograph 2 is transmitted to the differential circuit 3. Comparator 4. It is converted via the one-shot circuit 5 into a start signal synchronized with the R wave of the electrocardiogram waveform. This start signal is applied to the counter 3 as a synchronization signal for the unit scan and is used as a serato signal, and at the same time becomes a counter input to the counter 6. The output of this counter 6 determines the direction of each unit scan in each cycle of the electrocardiographic waveform.

A code converter 7 gives a delay time corresponding to the output of the counter 6 to a delay circuit 9. Further, each output of the counter 6° 13 is connected to a code converter 17. Based on these inputs, the code converter 17 outputs to the memory 23 the storage address of the scanning information corresponding to the received signal.

The reflected wave (echo) of the ultrasonic beam emitted from the probe 26 is received by the same probe 26, and the received outputs from each transducer element are added up by the adder circuit 15 via delay circuits 9 and 8. . This allows the signal to be received as a received signal with directivity in the transmission direction. Furthermore, the output from the adder circuit 15 is subjected to various corrections by the receiving circuit 18, and is made into a received information signal of a constant level.

It should be noted that the technique of this receiving circuit system uses a conventional technique, and a detailed explanation thereof will be omitted.

It should be noted that among the signal lines shown in the figure, all those with multi-bit data are expressed in a path format. The scanning control operation of the apparatus will be explained below.

Differentiating circuit 3 calculates the electrocardiogram waveform of the subject measured by electrocardiograph 2.
Differentiate with. A comparator 4 extracts the differential output from the differentiating circuit 3 indicating the rising point of the R wave in the electrocardiographic waveform. The output of the comparator 4 is input to the one-shot circuit 5 and synchronized with the R wave of the electrocardiographic waveform. The counter 13 is reset by this start signal pulse in order to synchronize its count number with the start signal.

On the other hand, the high frequency clock of the clock source 10 is frequency-divided by frequency dividers 11 and 12 and input to a counter 13.

When the counter 13 is reset as described above, it counts this frequency-divided clock from the value 101 and outputs the count value. As mentioned above, the counter 13 indicates the direction of transmission and reception of the ultrasonic beam. Therefore, counter 13
Since the count increases from the value 101 from the time when the start signal pulse is received, a unit scan is performed in synchronization with the start signal. The output value of the counter 13 is used by the code converter 14 to set the entire II extension time to be given to each vibrator in the code conversion delay circuit 8. The output frequency of the frequency divider 12 is sent as a pulse to the delay circuit 8-\.

Each ultrasonic vino is given a timing to fire all.

Furthermore, when the counter 4131-dimensional scanning area is counted with nine clocks corresponding to the number of ultrasonic beams to be scanned, the counted value automatically shifts to the value "0" and the operation of counting up is repeated. For this reason, the next starting word and moon pulse will arrive in one temple in the trench (b) [[
Repeated scanning becomes possible for the scanning range of η-.

6 counters to which the start signal pulse is input;
It counts and outputs the start signal pulses.

This count output value is provided so as to be shifted by a slight angle by the scanning area total delay circuit 91.tau. by the counter 13.

That is, when the counter 6 has a count value f1f, the scanning area consisting of the scanning line t+o-t11 in FIG. Consists of scanning a scanning area.

When the count value of counter 6 is 131, scanning line t'
The output count value corresponding to the scanning of the scanning area consisting of +Q % t 'In is supplied to the code converter 7 and the code converter 17 . The output count value supplied to the code converter 7 of the counter 6 is code-converted by the code converter 7, and the delay time of each vibrator is changed to 11 when the delay circuit 9 delays.
"1" is supplied to each element of the delay circuit 9. The delay time set in this delay circuit 9 changes with each cycle of the electrocardiogram waveform, and in order to uniformly direct the individual beams of each unit scan, the scanning direction of the unit scan is shifted. It turns out.

The received δ signals from each transducer of the probe material 26 obtained by scanning as described above are delayed by the delay circuit 9 and the delay circuit 8, and the delay is returned by the addition circuit 15 from the transmission direction of the super-hyperchonic beam. The signal waveform is obtained by emphasizing each signal component. This signal is attenuated in the depth direction by the receiving circuit 18 and input to the transducer 22 (Al1).

On the other hand, the memory 23 stores display data at an address corresponding to a display position on one display surface of the CRT 25. The output count value of the display counter 16, which controls the deflection of the display beam as a means for giving a read address to the memory 23, and the output count value of the counter 6, which defines the position of the scanning area and the position of the scanning line, is used as a means to give a write address. A code converter 17 is provided which receives the output count value of the counter 13 and generates an address corresponding to the display position corresponding to the scanning position of the ultrasonic beam. The count output of the display counter 16 and the count output of the code converter 17 are input to a multiplexer 27, and the multiplexer 27 alternately switches the read address and the write address in a time-sharing manner.
configured to provide. The output of the frequency divider 11 is connected to the memory 23 in synchronization with the switching timing of the multiplexer 27 so as to switch and designate the write mode.

As a result, the output of the A/'D converter 22 described above, that is, the digital value of the received signal at each write timing, can be written to an address that matches the display position of the memo IJ23. When reading the stored information, the display counter 16 gives a read address to the memory 23 as described above, and also provides the display control section 24 with the CRT 2.
A count output is provided to give the amount of XY deflection of the display beam of 5. The display control unit 24 converts the information read from the memory 23 into a volatility signal, and displays the display counter 16.
The 0 count value k is converted into an X-Y deflection amount and given to the CRT 25. Thereby, an image corresponding to the scanning of the ultrasonic beam can be displayed on the CRT 25.

As detailed above, according to the present invention, since the scanning direction of a unit scan is slightly shifted for each period of the electrocardiographic waveform of the subject, it is possible to further increase the scanning density of the ultrasound beam, and it is possible to display two images. The resulting tomographic images can also be obtained with higher resolution, making it possible to perform more precise ultrasonic diagnosis through tomographic image observation. In addition, each unit scan is performed in synchronization with the electrocardiogram waveform, and therefore, the unit scan is performed at the same phase point in each cycle of the electrocardiogram waveform, so we can repeatedly observe the same repetitive motion of the same tomographic image. can do.

[Brief explanation of drawings]

Fig. 1 is a diagram showing an example of a method of displaying a tomographic image in an ultrasonic diagnostic device, Fig. 2 is a time chart of ultrasonic scanning in the present invention, and Fig. 3 is a diagram showing the principle of the emission state of the ultrasonic beam in the present invention. The figure shown in FIG. 4 is a diagram showing an embodiment of the ultrasonic diagnostic apparatus of the present invention. 2 is an electrocardiograph, 6.
13 is a counter, 8 and 9 are delay circuits, 11° and 12 are frequency dividers, and 26 is a probe.

Claims (2)

[Claims] (1) In an ultrasound diagnostic device that obtains a tomographic image of a subject by transmitting and receiving ultrasound signals, there is an electrocardiograph that extracts an electrocardiogram waveform from the subject, and an electrocardiograph based on the electrocardiogram output from the electrocardiograph. a transmission timing generation circuit that determines the transmission timing of the ultrasonic signal; and a control unit that transmits the ultrasonic signal in synchronization with the transmission timing signal from the transmission timing generation circuit and extracts a reception signal corresponding to the transmission signal. What is claimed is: 1. An ultrasonic diagnostic apparatus comprising: transmitting and receiving ultrasonic signals in synchronization with an electrocardiographic waveform of a subject. (2) The control section has a scan direction control means for shifting the scan angle of the unit frame scan by a fixed angle every predetermined period of the scan timing signal, and the control section has a scan direction control means that shifts the scan angle of the unit frame scan by a fixed angle every predetermined period of the scan timing signal, and performs unit scans in different directions at the same phase of the electrocardiographic waveform. The ultrasonic diagnostic apparatus according to claim (1), characterized in that the ultrasonic diagnostic apparatus is configured to perform the following operations.