JPH03205039A - Ultrasonic diagnostic device for two dimensionally displaying blood flow speed distribution image in inspected body - Google Patents

Abstract

PURPOSE:To detect the low blood flow speed with high sensitivity without accompanying with the deterioration of frame rate by taking the data in 1/n intervals of the beating number of ultrasonic waves without varying the beating cycle of the supersonic wave supplied from a supersonic wave transmission/receiving means. CONSTITUTION:In a calculation control circuit 13, each operation of a shift object detecting filter 6 and a speed calculation circuit 7 is controlled so as to operate in n (n is an integer of 2 or more) systems or more, and doppler calculation processing is carried out in a rate of one for n (n is an integer of 2 or more) for N-pieces of data in each transmission/receiving direction of the echo signals which are taken by a contactor 1, transmission control circuit 2, and a received wave amplifying phase adjusting circuit 3 by the above described control operation, and this processing is carried out for each transmission/receiving direction, and each blood flow speed distribution display signal in plural directions is generated. In a display circuit 15, the outputted calculation data is writing-added in correspondence with the ultrasonic scanning line by the inside frame memory, and sent into a monitor 16, and displayed in two dimensional figure as blood flow speed distribution image.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an ultrasonic diagnostic apparatus that uses the Doppler effect of ultrasound to display a blood flow velocity distribution image in a two-dimensional manner at a diagnostic site of a subject. In particular, the present invention relates to an ultrasonic diagnostic apparatus that is capable of measuring low-speed blood flow without changing the emission period of ultrasonic waves, and is also capable of sensitively detecting low-speed blood flow signals without deteriorating the frame rate.

[Conventional technology]

As shown in FIG. 9, a conventional ultrasonic diagnostic apparatus of this type includes a probe 1 that transmits and receives ultrasonic waves to and from a subject, and a transmitter that controls the probe 1 to transmit ultrasonic waves. A control circuit 2, a reception amplification phasing circuit 3 that amplifies and phases the ultrasound signal reflected and received from the subject, and a Doppler signal that demodulates the reception signal from the reception amplification phasing circuit 3. A demodulation circuit 4 extracts only the shifted component, an A/D converter 5 digitizes the output signal from the demodulation circuit 4, and an A/D converter 5 that inputs this digitized Doppler signal to remove unnecessary components inside the subject. A moving target detection filter 6 that removes low frequency signals, a velocity calculation circuit 7 that inputs the Doppler signal from which unnecessary low frequency signals have been removed and calculates blood flow specifications within the subject, and data of the calculation results. and a display circuit system 8 that converts the image into an analog signal and displays a blood flow image. In FIG. 9, a detection circuit 9 and an A/D converter 10 are provided on the output side of the receiving wave amplification phasing circuit 3 in parallel with the blood flow image data processing system. The system is designed to process normal tomographic data.

The timing diagram shown in FIG. 10 shows the operation of ultrasonic wave transmission and reception in the conventional device configured as described above. Here, the configuration of the moving target detection filter 6 is a first-order cancellation filter, the number of ultrasound additions per direction is 8 (see Figure 10(c)), and the number of lines forming the B-mode image is 30. (See FIG. 10(b)). In this case, if the repetition period of the ultrasonic ejection signal is, for example, 4 KHz as shown in FIG. 10(a),
The maximum detection speed is ±2 KHz, and the frame rate at this time is 13.3 frames/second.

[Problem to be solved by the invention]

However, in such conventional ultrasound diagnostic equipment,
Since the moving target detection filter 6 is composed of a first-order cancellation type filter, it is difficult to detect low-speed blood flow signals with high sensitivity. In order to cope with this and detect even low-speed blood flow signals with high sensitivity, the repetition period of the ultrasonic ejection signal shown in FIG. 10(a) may be made slower. for example,
By slowing down the repetition period of the ultrasonic ejection signal from 4Kl (z) to 2Kl (z), the ability of the moving target detection filter 6 to detect low-speed blood flow signals can be improved. For example, as shown in FIG. Regarding the characteristics of the moving target detection filter 6, for a low-velocity blood flow signal of 400 mA, the attenuation amount when the repetition period of the ultrasound ejection signal was 4KHz, which is shown by the solid line, was approximately -20 dB, as shown by the broken line. If the launch frequency is slowed down to 1/2 of 4KHz, or 2KHz, the attenuation will be about -9dB, and the detection sensitivity will improve by about 11dB.However, with this countermeasure, under the same conditions as above, The frame rate deteriorated to about 6.7 frames/second, which is half of the previous rate.As a result, when displaying images of fast-moving parts such as blood flow in the heart, the display is slow. This resulted in images that were difficult to diagnose.As a result, the diagnostic performance of the device was sometimes reduced.

Accordingly, one object of the present invention is to provide an ultrasonic diagnostic apparatus that can solve these problems and display a two-dimensional blood flow velocity distribution image within a subject.

[Means to solve the problem]

In order to achieve the above objects, (1) an ultrasonic diagnostic apparatus that displays a two-dimensional blood flow velocity distribution image within a subject according to the present invention uses ultrasonic waves at a predetermined period in a certain direction of a part of the subject that has blood flow; A transmitting/receiving means that performs ultrasonic scanning to capture echo signals by sequentially moving in the transmitting/receiving direction while transmitting and receiving a beam N times.

Doppler calculation processing is performed on the N pieces of data for each transmission and reception direction of the echo signal taken in by this transmission and reception means at a rate of one piece for every n pieces (an integer of n≧2), and this processing is performed for each transmission and reception direction. The apparatus includes means for generating blood flow velocity distribution image display signals in a plurality of directions by performing the above-mentioned blood flow velocity distribution image display signals, and means for two-dimensionally displaying the generated blood flow velocity distribution image display signals.

Further, another configuration of the ultrasonic diagnostic apparatus of the present invention includes a means for transmitting and receiving ultrasonic waves into the subject, and a means for transmitting ultrasonic beams in a plurality of directions cyclically at a predetermined repetition period by the transmitting and receiving means. , a transmission/reception control means for controlling the reception to be performed multiple times per reception direction while changing the reception direction, a demodulation circuit for demodulating the received signal from the transmission/reception means, and converting the output signal of the demodulation circuit into a digital signal. A/D
Doppler signal detecting means having a converter and extracting a signal subjected to a Doppler shift caused by blood flow within the subject from the echo signal received by the transmitting/receiving means and the transmitting/receiving control means, and from the A/D converter. The Doppler signal detection method includes a moving target detection filter that removes a low frequency component signal from the received echo signal that is output, and a velocity calculation circuit that obtains blood flow velocity information from the signal from which the low frequency component signal has been removed. Generating a signal displaying a blood flow velocity distribution image from the output signal of the means, and cyclically generating a blood flow velocity distribution image display signal corresponding to each ultrasonic reception direction performed cyclically at each predetermined repetition period. means for outputting, and means for storing the cyclically output blood flow velocity distribution image display signal for each receiving direction;
and means for displaying the output signal from the storage means as a two-dimensional blood flow velocity distribution image.

Furthermore, in order to display a normal tomographic image, the echo signals received by the ultrasonic transmitting/receiving means and the transmitting/receiving control means are input to a tomographic image signal generating means including a detection circuit and an A/D converter. The apparatus is configured to generate a tomographic image signal and output it to the storage means.

Further, for two-dimensional display of the blood flow velocity distribution image, the moving target detection filter and the velocity calculation circuit are provided to generate a signal for displaying the blood flow velocity distribution image and output the signal cyclically. A plurality of sets of means are provided in parallel, a changeover switch means is provided for selectively outputting the output signal from the means to the storage means, and means is provided for cyclically switching the changeover switch of the changeover switch means in accordance with the ultrasonic reception direction. You can.

Furthermore, the moving target detection filter includes a pair of memories that store signals from the ultrasonic reception direction that change cyclically and are sequentially output from the A/D converter in the order of input and for each round; A control circuit that alternately writes and reads data to and from the memory, and subtracts the data directly output from the A/D converter and the data output from the memory by matching the ultrasonic reception directions. It may also be configured with an adder that outputs

[For production]

The ultrasonic diagnostic apparatus configured in this way that displays a two-dimensional blood flow velocity distribution image inside the subject can acquire data without changing the emission period of the ultrasonic waves from the ultrasonic transmitting/receiving means. By setting the interval to 1/n, the number of data to be captured is maintained, thereby preventing the frame rate from decreasing without reducing the amount of data for display. As a result, it is possible to produce the same effect as changing the ultrasonic launch period to 1/n. This results in
Even low-speed blood flow signals can be detected with high sensitivity.

Further, in another configuration example of the ultrasonic diagnostic apparatus of the present invention, the number of data to be captured can be maintained by transmitting and receiving ultrasonic waves in multiple directions without changing the emission period of the ultrasonic waves from the ultrasonic transmitting and receiving means. This prevents the frame rate from dropping without reducing the amount of data for display. As a result, even low-speed blood flow signals can be detected with good sensitivity.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a block diagram showing a first embodiment of an ultrasonic diagnostic apparatus according to the present invention. This ultrasonic diagnostic device uses the Doppler effect of ultrasound to display a two-dimensional image of the blood flow velocity distribution at the diagnostic site of the subject. The aim is to detect low-speed blood flow with high sensitivity, and as shown in FIG. A circuit 4, an A/D converter 5, a moving target detection filter 6, a speed calculation circuit 7, and a 1-display circuit system 8.
Detection circuit 9, A/D converter 10, and arithmetic control circuit 13
It consists of:

The probe 1 transmits and receives ultrasonic waves toward a diagnostic site of a subject, and is provided with a transducer that actually emits ultrasonic waves and receives reflected waves.

The wave transmission control circuit 2 is provided with a wave transmission path, a pulse generator, a wave transmission delay circuit, etc. to control the probe 1 and direct the ultrasonic waves to the diagnostic site. The wave receiving tank @ phasing circuit 3 is for amplifying and phasing the ultrasonic signal reflected from the diagnostic site within the subject and received by the probe 1. Although not shown, there is a wave receiving tank inside it. An amplifier and phasing circuit are provided. The demodulation circuit 4 demodulates the received signal output from the received wave amplification phasing circuit 3 and extracts only the component subjected to Doppler shift. The A/D converter 5 receives the Doppler signal output from the demodulation circuit 4 and digitizes it.

The moving target detection filter 6 inputs the Doppler signal digitized by the A/D converter 5 and removes unnecessary low frequency signals within the subject.
The Doppler signal from which unnecessary low-frequency signals have been removed by the moving target detection filter 6 is input to calculate blood flow parameters such as blood flow velocity, velocity dispersion, and reflection intensity within the subject.

and.

The display circuit system 8 converts the data calculated by the moving target detection filter 6 and the speed calculation circuit 7 into analog signals to display a two-dimensional blood flow image, a frame memory, a D/A converter, etc. It has a display circuit 15 consisting of a display circuit 15, and a monitor 16 consisting of a CRT or the like, and displays only a blood flow image, only a normal tomographic image, or a superimposed display of a normal tomographic image and a blood flow image. It looks like this.

Further, in FIG. 1, a detection circuit 9 and an A/D converter 1, which are provided in parallel with the blood flow image data processing system on the output side of the wave receiving amplification phasing circuit 3, are connected to the probe. 1, a wave transmitting control circuit 2, and a wave receiving amplification phasing circuit 3 input the echo signals received to generate a tomographic image signal and output it to the display circuit 15. It is designed to process image data.

Here, in the present invention, an arithmetic control circuit 13 is connected to the moving target detection filter 6 and the speed arithmetic circuit 7. This calculation control circuit 13 includes the moving target detection filter 6 and the speed calculation port II! The operation of r7 is expressed as n (
n≧2 (an integer) Doppler calculation processing is performed on N pieces of data per transmission/reception direction at a rate of one piece for every n pieces (an integer of n≧2), and this processing is performed for each transmission/reception direction to create blood flow velocity distribution images in multiple directions. It is adapted to generate a display signal.

The present invention is characterized by the provision of this arithmetic control circuit 13 and its control operation.

Next, the operation of the ultrasonic diagnostic apparatus of the present invention configured as described above will be explained with reference to FIGS. 1 and 2.

First, the probe 1 shown in FIG. 1 is brought into contact with the body surface of the subject toward the diagnosis site, and ultrasonic waves are transmitted and received. At this time, the probe 1 sends a fan-shaped signal inside the subject as shown in FIG. Ultrasonic waves are emitted in multiple directions. The order in which the ultrasonic waves are emitted is as shown in Figure 3, from the edge of the sector to a line calm of, for example, 1, 2, 3 degrees..., 3 degrees.
0 and the number of ultrasonic scanning lines is 30, Fig. 2 (b
), the predetermined interval 1 is set for line address 1.
For example, transmit 10 times in succession at a frequency of 1/4 KHz, and then transmit 10 times in the same manner in the direction of line address 2.
Send twice consecutively. Further, the line address is sequentially moved and this transmission is repeated until line address 30 is reached, and the inside of the subject is scanned in the fan shape, and a total of 300 ultrasonic beams are transmitted.

When ultrasonic waves are transmitted from the probe 1 in this way, as the ultrasonic waves emitted from each of the transducers travel inside the subject, they are reflected at tissue interfaces with different acoustic impedances, and they also affect the blood flow. Reflected waves with a Doppler shift are generated from moving tissues such as the heart. These reflected waves are then received by each of the vibrators. Here, each transducer of the probe 1 is connected to an amplifier that amplifies a minute received signal, and the received signal is amplified. Each amplified received signal is processed by a delay circuit in the receiving amplification phasing circuit 3.
The reflected signals in the transmission direction are phase-controlled so that they arrive at each vibrator at the same time, and the outputs of each delay circuit are added by an adder and sent to the demodulation circuit 4. In this way, the ten receiving beam signals in each receiving direction are input to the demodulation circuit 4 in the above order. Then, the line address is sequentially moved in response to the transmission, and transmission and reception are performed. The signal input to the demodulation circuit 4 is demodulated, and only the component that has undergone Doppler shift is sent to the A/D converter 5. The A/D converter 5 converts the input signal into a digital signal and sends it to the moving target detection filter 6.

The moving target detection filter 6 removes low frequency signal components from parts of the input signal that move at a slower speed than the blood flow and stationary parts, and sends the signal from which unnecessary low frequency signals have been removed to the speed calculation circuit 7. Send to. The speed calculation circuit 7 has a circuit for calculating blood flow information such as blood flow speed, speed dispersion, and reflection intensity, as described in, for example, U.S. Pat. No. 4,840,180. The above blood flow information is calculated and output based on the signal output from the moving target detection filter 6.

Here, in this embodiment, the moving target detection filter 6
The arithmetic circuit system consisting of the speed arithmetic circuit 7 and the speed arithmetic circuit 7 is controlled by the arithmetic control circuit 13 in accordance with the timing of ultrasound transmission and reception as follows. Now, in FIG. 3, the line storm for ultrasonic transmission and reception is assumed to be 1. As shown in FIG. 2(b), the ultrasonic launch period is 1 for line address 1.
When transmission and reception are performed continuously and repeatedly at /4 KHz, the received signal is io,
1. , 12, . . . , 1 are successively inputted to the moving target detection filter 6 via the receiving amplification phasing circuit 3, the demodulation circuit 4, and the A/D converter 5. At this time, the arithmetic control circuit 13 receives every n (an integer of n≧2) received signals,
For example, when n = 2, the signals 1° and 1□ are surrounded by solid hexagons in FIG. 2(C).

14. Operate the moving target detection filter 6 and the speed calculation circuit 7 of the first system in response to the IG input, as shown in FIG.
The signals 11°1, . 1. ．．
1. When inputting, the moving target detection filter 6 of the second system
and the speed calculation circuit 7 are operated. Then, the moving target detection filter 6 of the first system sequentially receives the input signals 1°, 1□j 149 il! 1 is used to find the difference between the signals 1o and 1□, the signals 1° and 12 from stationary objects are removed, and only the signal of the phase component corresponding to the velocity of the moving tissue is output. Similarly, the signals 1□, 14, 1
Between 4 and 16, the signal component from the stationary object is removed and only the phase component signal is output. The output signal of the moving target detection filter 6 of the first system is inputted to the speed calculation circuit 7 of the first system, and is calculated as the blood flow information in the speed calculation circuit 7 of the first system. 15.

Further, the moving target detection filter 6 of the second system uses the sequentially input signal 1□T 1391511'l to detect 1
The difference between the signals 1 and 1□ is determined, and the signal 11 and that from a stationary object in the IJ are removed, and only a signal with a phase component corresponding to the speed of the moving tissue is output. Similarly, signals 1 .
and 1s, 1. and 17, the signal component from the stationary object is removed and only the phase component signal is output. The output signal of the moving target detection filter 6 of the second system is input to the speed calculation circuit 7 of the second system, and is calculated as the blood flow information in the speed calculation circuit 7 of the second system. 15.

Then, the display circuit 15 writes and adds the calculation data output from the speed calculation circuit 7 in its internal frame memory in correspondence with the ultrasonic scanning line. Therefore, the second
As shown in Figure (c), for example, four beam data are written and added for line address 1, and this is repeated up to line address 30. When writing is completed up to line address 30, the sector shape shown in Figure 3 is created. This means that cross-sectional blood velocity distribution image data has been detected. Next, these blood flow velocity distribution image data are read from the frame memory, A/D converted, and sent to the monitor 16, where they are displayed two-dimensionally as a blood flow velocity distribution image.

Next, a more detailed explanation of the first embodiment will be given with reference to FIG. FIG. 4 is a block diagram showing the internal configuration of the moving target detection filter 6 in the first embodiment.

In this embodiment, the configuration of the arithmetic circuit system consisting of the moving target detection filter 6 and the speed arithmetic circuit 7 shown in FIG. The target detection filter 6 and the speed calculation circuit 7 operate as two or more systems. The internal configuration of the moving target detection filter 6 in this embodiment is as shown in the block diagram shown in FIG. This moving target detection filter 6 is a -order elimination type filter, and is a first static RAM (rS
-RAMJ) 17, an input-side inverter 18a and an output-side inverter 18b connected to its input/output terminals, and a second 5-RAM 19 connected in parallel to the first 5-RAM 17. , an input-side inverter 20a and an output-side inverter 20b connected to their input/output terminals, and the first or second 5-RAM 17.19.
and an adder 21 that adds the output signal from the A/D converter 5 and the output signal from the A/D converter 5.

Next, the operation of the moving one-edge detection filter 6 configured as described above will be explained with reference to FIG. 5. First, the operation from emitting an ultrasonic wave with the probe 1 to receiving the echo signal and performing A/D conversion proceeds in the same manner as in the embodiment shown in FIG.

The repetition period of the ultrasonic ejection signal at this time is, for example, 4 KHz as shown in FIG. 5(a). The Doppler signal digitized by the A/D converter 5 is
The signal is supplied to a moving target detection filter 6 shown in FIG. At this time, gate control signals ○C1 and OC2 are sent from the arithmetic control circuit 13, and the first gate control signal oC1 is applied to the inverter 18a on the input side of the first 5-RAM 17 and the output side of the second 5-RAM 19. The second gate control signal ○C2 is input to the inverter 18b on the output side of the first 5-RAM 17 and the inverter 20a on the input side of the second 5-RAM 19, respectively.

The first gate control signal OC1 is as follows.

As shown in FIG. 5(c), in synchronization with the repetition period of 4 kHz of the ultrasonic ejection signal shown in FIG. At the timings of ■ and ■, the signal level is “H”.
”, the signal level “L” and at Hu are alternately repeated.

On the other hand, the second gate control signal OC2 is as shown in FIG.
As shown in d), for example, at times ■ and ■, the signal level becomes 'H'', and at time ■.

The signal level "L11" and "H" are alternately repeated in the opposite relationship to the first gate control signal OC1 so that the signal level becomes "L" at the timing (2). When the above-mentioned first and second gate control signals OC1 and ○C2 are at the level "L", the first and second 5-RAM17.19 are respectively in the writing state, and when the level it Hu is, they are in the reading state. Become. As a result, Fig. 5(e) and (f)
As shown in 1, for example, at the timing of time ■, ■, the first gate control signal OC8 is at the level ttL''.
When , the first 5-RAM17 is used for writing (Write).
In the state e), data from the A/D converter 5 is written, and at the same timing as above, the second gate control signal OC2 becomes level 1 (H71, and the second 5-RAM 19 is in the read state). Then, the data written at the previous timing is read out. Furthermore, when the first gate control signal oC1 becomes level "H" at the next timings ■ and ■, the first 5-RAM 17 enters the read state and the data written at the previous timing is read out. is,
At the same timing as above, the second gate control signal OC2 becomes level "L II", and the second 5-R
The AM 19 enters a write state, and data from the A/D converter 5 is written.

Further, as shown in FIG. 4, the most significant bit control signal S3 is sent from the arithmetic control circuit 13 to the -th and second 5-RAMs 17.19. This most significant bit control signal S, as shown in FIG. 5(g), changes signal levels 11 L II and ri Htr in synchronization with the repetition period of 4 KHz of the ultrasonic ejection signal shown in FIG. 5(a). are controlled to repeat alternately.

The most significant bit control signal S at the signal level "L" is the MSB of the first or second 5-RAM 17, 19.
When input to the terminal, data is written to a lower address, and when the most significant bit control signal S1 of signal level tz H+t is input, data is written to an upper address. As a result, for example, at times ■ and ■, data 1° and 1□ of line addresses 1 and 2 shown in FIG.
They are written to the lower and upper addresses of AM17, respectively, and at the next times ■ and ■, data 1□ and 13 of line addresses 1 and 2 shown in FIG. 5(b) are written.
are written to the lower address and upper address of the second 5-RAM 19, respectively, in FIG.

At this time, at the same time as the above-mentioned times ■ and ■, data 1 of the line address 1 written at the previous time and ■ is stored in the first 5-RAM 17 as shown in FIG. 5(e).
゜, 11 are read, and an adder is added between data 1□ of line address 1 output from the A/D converter 5 shown in FIG. 4 at the timing of time ■ and data 1 ゜ of line address 1 read above 21, the subtraction is performed and the result is shown in Figure 5 (
As shown in h), at the timing ■, an output signal S4 of 1□-1° is sent out. Similarly, at time ■, the adder 21 performs subtraction between the data 13 of line address 1 outputted from the A/D converter 5 and the data 1□ of line address 1 read above. , as shown in FIG. 5(h), 1. -11 output signal S4 is sent out. From now on, such operations will be repeated as shown in Figure 5 (
As shown in e) and (f), the first 5-RAM 17 and the second 5-RAM 19 are alternately and repeatedly operated.
Even in the embodiment in which the output signal S4 as shown in h) is generated and sent to the next speed calculation circuit 7, the repetition period of the ultrasonic ejection signal is equal to 2 KHz, so its characteristics are as follows. This is the same as that shown by the broken line in FIG. 11, and the detection ability can be improved for, for example, 4007 low-speed blood flow signals.

Note that the frame rate at this time is such that the repetition period of the ultrasonic ejection signal is 4K) as shown in FIG. 5(a).
Therefore, if other conditions are kept the same as before, the frame rate will be 13.3 frames/second, and the frame rate will not deteriorate.

In addition, in Fig. 4 and Fig. 5,
- Although a case has been shown in which only the most significant bit of the RAM 17.19 is controlled and ultrasound data of two scanning lines are processed, the present invention is not limited to this. Line ultrasound data may also be processed. In this case, the repetition period of the ultrasonic ejection signal can be made equal to, for example, 4/3 KHz or 4/4 KHz, and even low-speed blood flow signals can be detected.

In this way, in this embodiment, the signals 1° to 1□ taken into the moving target detection filter 6 at a frequency of 1/4 KHz are
Among them, 1°, 1□t 1411G or 1,,L,
15. By performing arithmetic processing by skipping data one by one as shown in L, the processing cycle of the moving target detection filter 6 can be lengthened to 1/2 KHz. This means that the emission period of the ultrasonic waves emitted from probe 1 is 1/2K.
The effect is equivalent to that of setting the frequency to Hz, and it becomes possible to detect low-speed blood flow with high sensitivity without reducing the frame rate.

FIG. 6 is a timing IIA diagram showing another example of the operation of the moving target detection filter 6 shown in FIG. 4. The operations shown in this timing diagram include the writing of ultrasonic line address data shown in FIG. 6(b) and the generation of the output signal S4 of the moving target detection filter 6 shown in FIG. 6(h). The operation is different from that shown in FIG. That is, the fourth
As shown in the figure, the most significant bit control signal S1 is sent from the arithmetic control circuit 13 to the first and second 5-RAMs 17.19. This most significant bit control signal S2 is
As shown in FIG. 6(g), the signal levels "Ljl" and "Ht+" are controlled to repeat alternately in synchronization with the repetition period of 4 KHz of the ultrasonic ejection signal shown in FIG. 6(a). . Then, the most significant bit control signal S of signal level ttL'' is applied to the first or second 5-RAM 17.19.
When input to the MSB terminal of , data is written to the lower address, and when the most significant bit control signal S of signal level 11 HD is input, data is written to the upper address. As a result, for example, at times ■ and ■.

Data 1° and 2 for line addresses 1 and 2 shown in FIG. 6(b). In the same figure (e), the first 5-RAM17
are written to the lower and upper addresses of
At the next times ■ and ■, data 11, . . . at line addresses 1 and 2 shown in FIG. 2. are written to the lower address and upper address of the second 5-RAM 19, respectively, in FIG.

At this time, at the same time as the above-mentioned times ■ and ■, data 1° of line addresses 1 and 2 written at the previous time and ■ are stored in the first 5-RAM 17 as shown in FIG. 6(e). , 2° is read out, and line address 1 is output from the A/D converter 5 shown in FIG. 4 at time ■.
Data 11 and.

The adder 21 performs subtraction between the read data 1° of the line address 1, and as shown in FIG.
4 is sent. Similarly, at time ■, data 2. of line address 2 is output from the A/D converter 5. The adder 21 performs subtraction between the read data 2 and the data 2 of the line address 2, as shown in FIG.
As shown in h), 2. An output signal S4 of -2o is sent out. From now on, such operations will be repeated as shown in Fig. 6(e) and (f).
As shown, the first 5-RAM17 and the second 5-RA
M19 is alternately repeated to generate an output signal S4 as shown in FIG. 6(h) and send it to the primary speed calculation circuit 7. In this operation as well, since the repetition period of the ultrasonic ejection signal is equivalent to 2 kHz, its characteristics are the same as those shown by the broken line in FIG.
0) It is possible to improve the detection ability of 1z low-speed blood flow signals. In addition, the frame rate at this time is
As shown in Fig. 6(a), the repetition period of the ultrasonic ejection signal is 4 KHz, so if other conditions are kept the same as before, it will be 13.3 frames/second, which will cause a deterioration of the frame rate. Never.

FIG. 7 is a block diagram showing a second embodiment of the present invention. This embodiment uses the moving target detection filter 6 shown in FIG.
A plurality of sets (lla, 1lb) of arithmetic circuit systems each consisting of a speed arithmetic circuit 7 and a speed arithmetic circuit 7 are provided in parallel, and a switch 12 is provided for selectively outputting the output signal to the display circuit 15.
Moreover, the switching operation of this switch 12 is controlled by an arithmetic control circuit 13. The reason for providing two systems (ILa, 1lb) of the above-mentioned arithmetic circuit systems is to reduce the data acquisition in one direction to 1/2 of the number of ultrasonic waves emitted, that is, even though two waves of ultrasonic waves are emitted. On the other hand, this is to ensure that one piece of data is taken in one direction. Further, the switching device 12 includes the two arithmetic circuit systems 11a,
By connecting the switch 14 to the contact a side, the first arithmetic circuit system 11a is selected, and by connecting the switch 14 to the contact side, the second arithmetic circuit system 1 ], b is selected. It is now selected.

The arithmetic circuit systems 11a, llb and the switch 12 are controlled by an arithmetic control circuit 13.

That is, the control signal S1 output from the arithmetic control circuit 13 controls the operation of the moving target detection filter 6 and the speed arithmetic circuit 7 of the arithmetic circuit systems 11a and 11b, and the switching signal S2 operates the switch 12. The output signals from the two arithmetic circuit systems 11a and llb are switched over.

Next, the operation of the ultrasonic diagnostic apparatus according to the second embodiment configured as described above will be explained with reference to FIG.

First, under the control of the wave transmission control circuit 2 shown in FIG. 7, the probe 1 detects the diagnostic site of the subject.

For example, an ultrasonic beam is emitted toward the heart or abdomen. At this time, the ultrasonic waves are ejected alternately in two different directions each time the ejecting signal is output, as shown in FIG. 3 described above. This is because, in order to avoid changing the ultrasonic emission cycle, when data is not captured in a certain direction, ultrasonic waves are emitted in a different direction and data in that direction is attempted to be captured. The repetition period of the ultrasonic ejection signal is set to 4 KHz, for example, as shown in FIG. 8(a). Then, each reflected wave from the launch direction is sequentially and alternately received by the probe 1,
Each of the received signals is amplified and phased by a receiving amplification phasing circuit 3. Next, the received signal from the received wave amplification phasing circuit 3 is demodulated by the demodulation circuit 4, and only the component subjected to the Doppler shift is extracted. The Doppler signal output from this demodulation circuit 4 is as follows.

The signal is input to the A/D converter 5 and converted into a digital signal.

Then, this digitized Doppler signal is transmitted to the first and second arithmetic circuit systems 11a and 11a, which are provided in parallel.
lb.

At this time, a control signal S is sent from the arithmetic control circuit 13 shown in FIG.
In addition to controlling the operation timing of a and llb, a switching signal S2 is sent out to switch the switch 12 at a predetermined timing. As shown in FIG. 8(C), the above switching signal S2 alternates between signal levels IT L 7+ and PA H" in synchronization with the repetition period of 4 KHz of the ultrasonic ejection signal shown in FIG. 8(a). When the switching signal S2 of the signal level 11 L I+ is input to the switching device 12 shown in FIG. Only the system 11a operates.In addition, the switching signal S2 of signal level "H" is applied to the switching device 1.
2, the switch 14 is connected to the contact side, and only the second arithmetic circuit system 11b operates. As a result, as shown in FIGS. 8(d) and (e), the first arithmetic circuit system 11a and the second arithmetic circuit system 11b operate alternately and add the collected data. Therefore,
Ultrasonic waves are emitted from the probe 1 at 4 KHz, but the data output from the arithmetic circuit systems 11a and llb is the same as when emitting ultrasonic waves at 2 KHz in one direction of transmission and reception. Become. At this time, as shown in FIG. 8(b), the line address for constructing the ultrasonic image is also switched in response to the alternating repetition of it L +7 and "H11" of the switching signal S2, and the signal level is changed. is “L”
When I+, the addition data from the first arithmetic circuit system 11a is written to the frame memory of the display circuit 15, and the signal is 1'H.
In case of II, the added data from the second arithmetic circuit system 11b is written to an address different from the address to which the data of the first arithmetic circuit system 11a is written. In other words, Fig. 8 (
As shown in a), the repetition period of the ultrasonic ejection signal is set to 4.
KHz, each arithmetic circuit system 11a, llb
For this purpose, the repetition period of the ultrasonic launch signal is 2KHz.
and each arithmetic circuit system 11a, llb
In this case, data subjected to Doppler shift is collected at a cycle twice as long as the repetition cycle of the actual ultrasonic launch signal.

If the moving target detection filter 6 of each arithmetic circuit system 11a, llb shown in FIG.
By making it equivalent to KHz, its characteristics become the same as those shown by the broken line in FIG. 11, and the detection ability for, for example, 4007 low-speed blood flow signals can be improved. Note that the frame rate at this time is such that the repetition period of the ultrasonic launch signal is 4Kl (as shown in FIG. 8(a)).
z, so if other conditions are the same as before, it will be 13.3
The frame rate is one frame per second, and there is no deterioration in frame rate.

In this way, the ability to detect low-speed blood flow signals is improved in the moving target detection filter 6 of each arithmetic circuit system 11a, llb, and the apparent repetition period of the ultrasonic wave ejection signal is twice the actual repetition period. The data calculated by the velocity calculation circuit 7 as a signal with a period of , is displayed under display control by the display circuit 15, and then a blood flow image is displayed two-dimensionally on the monitor 16.

On the other hand, in a normal tomographic image, the received signal output from the received wave amplification phasing circuit 3 shown in FIG. 10, it is converted into a digital signal to become tomographic image data, and the tomographic image is superimposed on the blood flow image described above, or only the tomographic image is controlled to be displayed by the display circuit 15, and displayed on the monitor 16.

In addition, in FIG. 7, the calculation circuit system consisting of the moving target detection filter 6 and the speed calculation circuit 7 is divided into two systems (lla,
1 lb), but the present invention is not limited to this, and the present invention is not limited to this.For example, three systems, four systems, or more systems are provided, and the direction of emitting ultrasonic waves is, in the case of three systems, in three directions,
In the case of four systems, the operation may be repeated cyclically in four directions, and the number of contacts of the switching device 12 may be increased correspondingly.

In this case, the repetition period of the ultrasound ejection signal can be made equal to, for example, 473 KHz or 4/4 KHz, and even low-speed blood flow signals can be detected.

Further, in this embodiment, the calculation circuit systems 11a and llb are composed only of the moving target detection filter 6 and the speed calculation circuit 7,
Since the demodulation circuit 4 and the A/D converter 5 are integrated into one system, there is an effect that the circuit configuration is simplified. However, the demodulation circuit 4 and/or the A/D converter 5 may be provided for each arithmetic circuit system 11a, llb. Furthermore, in this embodiment, the transmission and reception directions are changed for each ultrasonic wave ejection cycle, but the transmission and reception may be kept constant and only the reception direction may be shifted by a small amount.

〔Effect of the invention〕

Since the present invention is configured as described above, by setting data acquisition at an interval of 1/n of the number of ultrasonic waves emitted from the ultrasonic transmitting/receiving means without changing the emission period of ultrasonic waves from the ultrasonic transmitting/receiving means, ultrasonic The same effect as changing the sound wave launch period to 1/n can be produced.

Thereby, low-speed blood flow can be detected with high sensitivity and without deterioration of frame rate.

Further, in another configuration example of the ultrasonic diagnostic apparatus of the present invention, the number of data to be captured can be maintained by transmitting and receiving ultrasonic waves in multiple directions without changing the emission period of the ultrasonic waves from the ultrasonic transmitting and receiving means. , thereby making it possible to prevent the frame rate from dropping without reducing the data for display. Furthermore, a control signal is sent from the arithmetic control circuit 13 to the moving target detection filter 6 and the speed calculation circuit 7, and this control signal causes the moving target detection filter 6 and the speed calculation circuit 7 to operate as two or more systems. It can be controlled as follows. Therefore, the moving target detection filter 6
And the repetition period of the apparent ultrasonic ejection signal to the speed calculation circuit 7 is twice or 3 times the actual repetition period.
The length can be doubled or longer, improving the ability to detect low-speed blood flow signals. At this time, since the repetition period of the actual ultrasound ejection signal is not particularly slowed down for the purpose of detecting low-speed blood flow signals, the frame rate does not deteriorate.

For this reason, the displayed image of a fast-moving region such as the blood flow in the heart will not be displayed in slow motion, and an image that is easy to diagnose can be obtained. Therefore, the diagnostic ability of the device can be improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a first embodiment of an ultrasonic diagnostic apparatus according to the present invention that two-dimensionally displays a blood flow velocity distribution image within a subject, and FIG. 2 is a timing diagram for explaining its operation. , FIG. 3 is an explanatory diagram showing the line address of ultrasonic waves emitted in a fan shape inside the subject, and FIG. 4 is a block diagram showing the internal configuration of the moving target detection filter in the first embodiment. , FIG. 5 is a timing diagram for explaining its operation, FIG. 6 is a timing diagram showing another example of the operation of the moving target detection filter shown in FIG. 4, and FIG. 7 is a timing diagram for explaining the second example of the present invention. A block diagram showing the embodiment, FIG. 8 is a timing diagram for explaining its operation, FIG. 9 is a block diagram showing a conventional ultrasonic diagnostic apparatus, and FIG. 10 is a timing diagram for explaining its operation. 11 are graphs showing the characteristics of the moving target detection filter in the present invention and the conventional example. 1... Probe, 2... Wave transmission control circuit, 3...
Receiving wave amplification phasing circuit, 4... demodulation circuit, 5, 10.
... A/D converter, 6... Moving target detection filter,
7...Speed calculation circuit, 8...Display circuit system, 9
...Detection circuit, lla, llb...Arithmetic circuit system,
13... Arithmetic control circuit.

Claims (5)

[Claims] (1) Transmitting/receiving means that performs ultrasound scanning by transmitting and receiving an ultrasound beam N times at a certain predetermined period in a certain direction of a region having blood flow within the subject, and sequentially moving in the transmission/reception direction to capture echo signals. Then, Doppler calculation processing is performed on the N pieces of data for each transmission and reception direction of the echo signal taken in by this transmission and reception means at a rate of one piece for every n pieces (an integer of n≧2), and this processing is applied to each transmission and reception direction. an in-subject device comprising: means for generating a blood flow velocity distribution image display signal in a plurality of directions; and means for two-dimensionally displaying the generated blood flow velocity distribution image display signal. An ultrasonic diagnostic device that displays a two-dimensional blood flow velocity distribution image. (2) means for transmitting and receiving ultrasound into the subject, and the transmitting and receiving means transmits ultrasound beams cyclically in multiple directions at a predetermined repetition period, multiple times per reception direction while changing the reception direction; The transmitting/receiving means includes: a transmitting/receiving control means for controlling the transmission/receiving means to perform reception at each time; a demodulating circuit for demodulating the received signal from the transmitting/receiving means; and an A/D converter for converting the output signal of the demodulating circuit into a digital signal; and a Doppler signal detection means for extracting a signal subjected to a Doppler shift caused by blood flow within the subject from the echo signal received by the transmission/reception control means; It has a moving target detection filter that removes component signals and a velocity calculation circuit that obtains blood flow velocity information from the signal from which the low frequency component signals have been removed, and the blood flow velocity distribution is determined from the output signal of the Doppler signal detection means. means for generating a signal for displaying an image and cyclically outputting a blood flow velocity distribution image display signal corresponding to each ultrasonic reception direction cyclically performed at each predetermined repetition period; It is characterized by comprising means for storing the output blood flow velocity distribution image display signal for each reception direction, and means for displaying the output signal from the storage means as a two-dimensional blood flow velocity distribution image. An ultrasonic diagnostic device that displays a two-dimensional image of blood flow velocity distribution within the subject. (3) The echo signal received by the ultrasonic transmitting/receiving means and the transmitting/receiving control means is input to the tomographic image signal generating means including a detection circuit and an A/D converter, thereby generating a tomographic image signal and storing the echo signal in the storage means. 3. The ultrasonic diagnostic apparatus according to claim 2, wherein the ultrasonic diagnostic apparatus is configured to output a two-dimensional image of blood flow velocity distribution within a subject. (4) A plurality of parallel sets of means are provided in parallel that have a moving target detection filter and a velocity calculation circuit to generate a signal that displays a blood flow velocity distribution image and output the signal cyclically, and select the output signal. 3. The method according to claim 2, further comprising a changeover switch means for outputting the output to the storage means, and means for cyclically switching the changeover switch of the changeover switch means in accordance with the ultrasonic reception direction. An ultrasonic diagnostic device that displays a two-dimensional blood flow velocity distribution image. (5) The moving target detection filter includes a pair of memories that store signals from the ultrasonic reception direction that change cyclically and are sequentially output from the A/D converter in the order of input and for each round; A control circuit that alternately writes data to and reads data from the memory, and subtracts the data directly output from the A/D converter and the data output from the memory by matching the ultrasonic reception directions. 3. The ultrasonic diagnostic apparatus for two-dimensionally displaying a blood flow velocity distribution image within a subject according to claim 2, further comprising an adder for outputting an output.