JPH0211250B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ultrasonic diagnostic apparatus that can effectively obtain, for example, a tomographic image of the heart as well as information on the circulation of blood flowing within the heart.

Ultrasonic diagnostic equipment has demonstrated great effectiveness in the medical field. Particularly in recent years, electronic scanning devices have been developed and are attracting attention because they can, for example, obtain tomographic images of the heart in real time. This type of device is described in "Measurement and Control" by Iinuma.
As detailed in Vol. 16, No. 12 (1977), page 901.

Now, in recent years, there has been a desire to simultaneously obtain, in addition to the above-mentioned tomographic image of the heart, the movement of blood flowing within the heart. For example, Mishima et al.'s 17th Japan ME
The device shown in Proceedings of the Academic Conference, p. 237 (1978) has been proposed. To briefly explain this device, a probe for ultrasonic Doppler measurement is attached to the probe of the diagnostic device via an arm, and the position of each probe is
And the direction of transmission and reception of the ultrasonic beam is detected by a potentiometer. Then, one probe obtains a real-time tomographic image, and the other probe observes the blood flow velocity from the Doppler deviation of the ultrasound. This type of device is very useful because it can obtain the above two pieces of information individually, and it can also obtain the two pieces of information simultaneously in relation to each other.
However, in actual clinical use, handling such as positioning the two probes is extremely inconvenient. In particular, since the heart has a complex shape and constantly beats, great care must be taken when setting a single probe. Therefore, it has been extremely difficult to position the two probes in relation to each other. Furthermore, in order to detect the set positional relationship, a fairly large arm, potentiometer, arithmetic device, etc. are required, making the configuration complicated.
Furthermore, because the directions of the ultrasound beams from each probe are different, the paths through which the ultrasound waves reach the reflective object are different, and at the same time, if there are differences in the ultrasound propagation speed along those paths, the accuracy of the potentiometer and arm may be affected. Coupled with this, there was a drawback that a shift occurred in the respective positional relationships, and an error occurred in the relevance of each detection result. Further, even if the tomographic image is clearly displayed, it is not possible to confirm whether the ultrasonic beam for blood flow measurement has reached a desired portion.

FIG. 1 shows the drawbacks of the conventional example, and assumes that the position for blood flow measurement is set at point po on a tomogram.
The sound speed setting for obtaining tomographic images and Doppler signals is Co, the actual average sound speed from the tomographic probe 61 to point P is C1, the round trip propagation time of the pulse is t1,
Let C2 be the actual average sound speed from the Doppler probe 62 to point p, and let t2 be the round trip propagation time of the pulse.
Since the sound velocity setting value for display is C0, the distance to point p0 in the tomographic image is C0t1, and in Doppler it is C0t2, but the actual average sound velocity is C1 and C2, respectively, so the distance to the detected point is respectively C1t1,
It is C2t2. Therefore, p0 displayed on the tomographic image
The true position of the point is shown in the tomographic image as shown in Figure 1.
From p0, (C1-C0)t is at p1, which is far away, and in the Doppler signal, (C2-C0)t2 is at p2, which is far away, and C1=C2=
If it is not C0, reflected signals at different positions will be detected.

In addition, at the position where the Doppler probe is placed, there is often tissue 63 between the probe and the heart that hardly transmits ultrasound, such as the lungs, so that the tomographic image is clearly depicted and the beam direction from which the Doppler signal is obtained is Even though the arms, potentiometers, and arithmetic circuits are clearly displayed on the display, it is unclear whether the ultrasonic beam for the Doppler signal has reached the target position. These drawbacks arise because the paths of the ultrasound beams for obtaining tomographic images and Doppler signals are different.

Furthermore, in conventional devices, the timing of emitting ultrasound pulses and the reference signal that is mixed into the ultrasound signal to extract the Doppler signal from the ultrasound signal containing the Doppler signal are not stable; There is a problem that the fluctuation itself is detected as a Doppler signal.

The present invention was made in consideration of these circumstances, and its purpose is to be able to obtain tomographic images with a single probe, as well as obtain blood flow velocity information due to the Doppler effect, and to It is an object of the present invention to provide an ultrasonic diagnostic device in which the timing of emitting sonic pulses and the reference signal for mixing with an ultrasonic signal and extracting a Doppler signal are stable.

The outline of the present invention is to divide the output of a reference oscillator that oscillates and outputs a signal at a precise frequency into an integer fraction to obtain a repetition frequency (rate period), drive the probe in pulses, and transmit ultrasonic waves. Then, the reflected ultrasound from the reflector is detected to obtain a real-time tomographic image, and the signal of the reflected ultrasound is mixed with a reference wave signal based on the output of the reference oscillator in a mixer, and its output is By filtering the information, information about blood flow is obtained. In this way, real-time tomographic images and information regarding blood flow are obtained and displayed simultaneously using the same ultrasound probe.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 2 is a schematic configuration diagram. The reference oscillator 1 is
For example, it is composed of a crystal oscillator, and the frequency
It oscillates and outputs a signal with highly stable frequency characteristics of 5MHz (20MHz). This oscillation output is input to a frequency divider 2 consisting of a flip-flop on one side and divided by two, and on the other side it is inverted by an inverter circuit 3 and then input to a frequency divider 4 where the frequency is divided by two. . Therefore, each output of the frequency dividers 2 and 4 becomes a signal with a frequency of 2.5 MHz, and has a phase difference of π/2. The output signal of the frequency divider 2 is supplied to the frequency divider 5, and is divided by N (N is an integer, e.g.
500) and output as a rate frequency signal with a frequency of 5kHz. This signal is supplied to the control circuit 6 and also to delay circuits 7a, 7b, . . . , 7n, respectively. These delay circuits 7a, 7
Delay times b, -, 7n are set by the control circuit 6, and the set delay time determines the transmission direction of the ultrasonic signal, which will be described later. The signals passed through the delay circuits 7a, 7b, . . . , 7n drive the pulsers 8a, 8b, . ,9b,~,
9n are respectively energized to transmit ultrasonic signals. Note that these vibrators 9a, 9b,
. . . , 9n are arranged, for example, in a straight line to form an array structure, forming an ultrasonic probe, that is, an electroacoustic transducer.

On the other hand, the signals reflected at the in-vivo reflection sites of the transmitted ultrasonic waves are transmitted through the ultrasonic transducers 9a and 9.
The waves are received at points b, -, and 9n, respectively. The received signal is transmitted to the preamplifiers 10a, 10b, . . . , 1
Delay circuits 11 whose delay times are set by the control circuit 6 after being amplified via the
A, 11b, -, 11n are subjected to delay control and output. Note that the delay circuits 11a, 11b, . . . , 1
Each set delay time of 1n is determined by the previous delay circuits 7a and 7.
The same values are defined corresponding to b, to, and 7n, respectively. Therefore, each delay circuit 11a, 11
The outputs of b, -, 11n are inputted to an addition/synthesis circuit 12, subjected to addition/synthesis processing, and outputted as a reception signal from the ultrasonic wave transmission direction. This output signal is detected via a detector 13 and supplied to a display device 14 as a tomographic information signal. Further, the output signal of the addition and synthesis circuit 12 is sent to a mixer (MIX).
15 and 16, respectively. These mixers 15 and 16 input the output signals of the frequency dividers 2 and 4, respectively, and the output signals, that is, the frequency 0 which is the reference for the rate frequency described above.
(2.5MHz) signal and the received signal are mixed. Each mixing output of mixers 15 and 16 is filtered by filter 1.
7 and 18, respectively, and then input to a phase comparator 19, where the phases of the signals are discriminated. For example, when the phase discrimination result is positive, it indicates that the blood flow is flowing toward the propagation direction of the ultrasonic signal, and when the value is negative, it indicates that the blood flow is flowing away from the ultrasonic signal. This information is input to and displayed on the display device 14.

Further, the output signal of the filter 17 is input to a range gate circuit 20. The circuit 20 is
The gate is opened by an MM 22 which is turned on for a predetermined period by the output of a monostable multivibrator (hereinafter abbreviated as MM) 21 which operates in response to the rate signal (output of the frequency divider 5). . In other words, the reflected ultrasound signals that are received continuously in time series are such that the reception time is proportional to the depth of the test area. Therefore, if an appropriate elapsed time is determined in the MM21 and a signal of a predetermined time width is obtained by operating the MM22 at the output timing, the range gate circuit 20 extracts only the diagnostic information signal of the desired observation site. It turns out. The output of this range gate circuit 20 is passed through a band pass filter (BPF) 2.
3, it is possible to obtain Doppler-shifted frequency component information, that is, a signal proportional to the blood flow velocity.

FIG. 3 is a waveform diagram of each part showing the operation of the device shown in FIG. This is the rate frequency signal with a frequency of 5kHz. The pulsers 8a, 8b, . . . , 8n are synchronized at each rising edge of the signal and are driven under delay time control. Therefore, from the transducers 9a, 9b, ~, 9n (probes), the rate period is as shown in Figure 3b.
Ultrasonic signals are transmitted every 200 μs. The center frequency (1) of the transmitted ultrasonic pulse is approximately 2.5MHz. When such a transmitted ultrasonic signal is reflected and received by various parts within the living body, the received signal becomes as shown in FIG. 3c. This received signal (output of the addition/synthesis circuit 12) is output as a signal as shown in FIG. .

The reflected wave from a fixed reflector has a waveform as shown in Figure 4a, and its frequency spectrum is as shown in Figure 4b, with a center frequency of 1 (approximately 2.5MHz).
It has a wideband frequency component including . In this state, it is impossible to detect extremely small Doppler shifts of about 1 kHz. However, when the pulse of Figure 4a is repeated at a rate frequency of exactly 5 kHz divided from an extremely accurate reference oscillator, as in the embodiment of the present invention, the frequency spectrum has an envelope of 1 as shown in Figure 4c. equal to the spectrum of pulses
The line spectrum consists only of frequencies that are integral multiples of 5kHz. Therefore, the reflected wave from the fixed reflector obtained by the circuit of FIG. 2 has a spectrum as shown in FIG. 4c. There is no problem because the pulsers and amplifiers have delay times, and the delay time caused by the delay circuit varies depending on the scanning direction, but is always equal in the constant scanning direction. FIG. 4d is an enlarged view of the horizontal axis, where the solid line is the reflected wave spectrum from a fixed reflector, while the chain line is the spectrum of the reflected wave from a moving object, which has undergone a Doppler shift of Δ. Therefore, by mixing this signal with the output of the frequency divider 4 (frequency 0) using a mixer and extracting the difference frequency, the Doppler deviation frequency can be detected.

If the line spectrum of the rate frequency signal is unstable with respect to the reference wave signal 0, the fluctuation of the rate frequency signal with respect to the reference wave signal itself is regarded as the Doppler shift frequency, and an accurate Doppler shift frequency can be obtained. things become difficult.

On the other hand, the mixer 15 mixes the received signal shown in FIG. 3c and the reference signal having a frequency of 2.5 MHz, which has been divided by two, to obtain a mixed output as shown in FIG. 3e. This signal is filtered through filter 17 and transformed as shown in FIG. 3f. Third
Figure g shows the sampling timing of the range gate circuit 20. By sequentially sampling the filter output shown in figure f at the same timing, the Doppler deviation component of the reflected ultrasound at one observation site is simultane- ously Obtained as shown in Figure h. FIG. 3i shows the time-base compressed signal shown in h, and by filtering this signal through the bandpass filter 23, a Doppler signal as shown in FIG. 3j is obtained. Thus, as the output of the detector 13, observation information on the tomographic image as shown in FIG. 3d is obtained, and as the output of the filter 23, observation information on the Doppler shift frequency regarding the blood flow velocity as shown in FIG. 3j is obtained at the same time. be able to.

Incidentally, although the control circuit 6 described in, for example, Japanese Patent Application No. 52-28016 is generally used, the following configuration is suitable for the present apparatus. That is, the control circuit 6 is provided with a ROM (read-only memory), and each address of the ROM is made to correspond to the scanning direction of the ultrasound waves. At each address, the delay circuits 7a, 7b, . . . , 7 necessary for transmitting and receiving ultrasonic waves in the scanning direction
Delay time setting information for n, (11a, 11b, . . . , 11n) is stored. Therefore, by selecting and specifying the ROM address corresponding to the specified scanning direction, the ultrasonic signal is transmitted in the specified scanning direction, reflected by a reflecting object, and received in the specified direction. become. Now, as shown in FIG. 5, the scanning direction of the ultrasonic signal transmitted and received by the probe 26 is 1, 2, to
~, 64. Assume that information about a position P in direction k is observed from a Doppler signal. In this case, the scanning direction specified by the ROM is set to “1,
k, 2, k, 3, ...'' If you specify the scanning direction k for every other rate pulse, and specify the timing of the other rate pulses sequentially from scanning direction 1, the Doppler By obtaining a signal and an M-mode signal, and specifying another direction, a B-mode, that is, a real-time tomographic image, can be obtained. In other words, real-time tomographic images and blood flow velocity information can be observed simultaneously. Also, at this time, the effective rate frequency of the B-mode and Doppler signals is 1/2 of the frequency shown above, that is, 2.5 kHz. Note that if the display output is configured to be luminance-modulated at the sampling timing by the range gate circuit 20, the blood flow observation position can be displayed accurately.

Now, the ultrasonic signals used for tomographic image and blood flow observation may both be single pulses, but for example, for a single pulse for tomographic image observation as shown in FIG. 6a, blood flow For observation, it is more convenient to use a waveform with a large amplitude level, as shown in figure b, or a burst-like waveform, with a large number of waves, as shown in figure e. By using such an ultrasonic signal, it is possible to improve the S/N ratio in blood flow observation without causing a decrease in distance resolution. Therefore, single pulse ultrasonic waves and burst waves are alternately transmitted from the ultrasonic probe 26 shown in FIG. 6d at a predetermined rate, and the scanning direction is set as shown in FIG.
By specifying as follows, both the tomographic image information and blood flow information described above can be set to a high S/N ratio with high distance resolution.
can be obtained as a good signal.

In the above description, blood flow observation was performed only at one location on one scanning line, but blood flow observation at multiple locations on one scanning line can be performed simultaneously. FIG. 7 shows an example of the frequency divider 5.
MM21, 22 forming the latter stage, a range gate circuit (RG) 20 as a Doppler signal extraction means,
A plurality of BPF23 etc. are provided in parallel to form a multi-channel configuration. That is, the output (rate signal) of the frequency divider 5 is passed through the gate circuit G31 gate-controlled by the flip-flop 30.
It is supplied to MM21a, 21b, -, 21n. The flip-flop 30 inputs a rate signal (frequency 0/2N) and performs an inverting operation, and the gate circuit 31 is opened only at the timing of transmitting and receiving ultrasonic waves in the scanning direction k mentioned above. Therefore, when transmitting and receiving ultrasonic waves in the scanning direction k, that is, when observing blood flow, the output of the frequency divider 5 is supplied to the MMs 21a, 21b, . . . , 21n. These MM21a, 21b, ~, 2
1n has pulse time widths set as shown in FIGS. 8a, c, and e, respectively. And MM22
a, 22b, ~, 22n are MM21a, 21b,
8b, d, f with a pulse time width of 4 μs, for example.
It outputs a signal with the timing shown in .
Now, suppose that the MMs 21a, 21b, . , filter 17
range gate circuits 20a, 20b, ~, 20
The received signal inputted to n is sequentially sampled corresponding to the depth shown in FIG. 8g.
In other words, the depth from the surface of the probe 26 is 20 mm, 23 mm,
Reflection information will be extracted at 3mm intervals from 26mm to 120mm. These reflection information are
After passing through BPF23a, 23b, ~, 23n, zero crossing detector (ZC) 32a, 32b, ~, 32
n, and the zero crossing timing of the output level is detected. These are ZC32a, 32b,
~, 32n calculates the Doppler deviation frequency from the zero crossing timing, for example, wave number voltage conversion (F/V conversion)
An amplitude signal proportional to the blood flow velocity is obtained and supplied to the recording device 33. Note that the zero crossing detector 32a,
32b, . . . , 32n may be anything that counts the number of zero crossings of a signal within a predetermined period of time, for example. A frequency analyzer may also be used instead.

Thus, Doppler deviation information, that is, blood flow information at multiple locations can be obtained simultaneously from one piece of ultrasound scanning information.

FIG. 9 shows the configuration of another embodiment in which Doppler deviation information at a plurality of locations is obtained simultaneously from one piece of ultrasonic scanning information. Flip Flop (FF) 35
functions similarly to the flip-flop 30 described above, and is fed together with the output of the frequency divider 5 to the gate circuit 36. The gate circuit 36 receives the signal from the frequency divider 5.
Frequency based on FF35 output of 5kHz signal
Outputs a 2.5kHz (0/2N) rate signal. As a result, Doppler signals corresponding to each depth are extracted. This rate signal is applied to a random access memory (RAM) 3 having an address structure as shown in FIG.
7 as a scanning control signal. That is,
For example, the RAM 37 has 64×64 addresses “1,
1” “1,2” ~ “1,64” “2,1” ~ “6
4,64'', and the output of the filter 17 is digitized and written via an A/D converter 38 to each address. Incidentally, information writing into the RAM 37 and reading which will be described later are controlled by a 400 kHz clock signal output from a clock oscillator 39.
Therefore, the ultrasound information obtained by one scan is sequentially converted into digital data and assigned to addresses "1,1", "1,
2" to "1,64" in sequence. Then, the next obtained ultrasonic one-scanning information is changed in line under the control from the gate circuit 36 and written in addresses "2,1", "2,2", "2,3" to "2,64". It will be done. Similarly, the 64th one-scan information is obtained from addresses "64,1", "64,2" to "64,6".
4” is written. In this case, the clock frequency is 400kHz, and the time required to write one scan information to one row of memory address is 64kHz.
Therefore, it is approximately 160 μs. This corresponds to a depth of approximately 0 to 12 cm at the observation site in one scan.
In addition, this Doppler scanning and B-mode scanning for tomographic image observation are performed alternately, and the rate interval between each is 400 μs.
It is becoming. Therefore, all information is written to all addresses (64×64) in the RAM 37 in 25.6 ms. It goes without saying that each address position corresponds to the depth of the observed region.

On the other hand, the information written as described above is now sequentially addressed column by column and read out. This readout is performed using a 400kHz clock signal as explained above. That is, first, information at addresses "1,1", "2,1", "3,1" to "64,1" is read out in the column direction, and then information at addresses "1,1", "3,1" to "64,1" is read out in the column direction.
Information of ``2'', ``2,2'', ``3,2'' to ``64,2'' is read out. Therefore, the same depth of the information series read out over a row of the above addresses, that is, the time course of the signal subjected to Doppler deviation at the same observation site, and therefore, as mentioned above, the output is restored via the D/A converter 40, smoothed via the filter 41, and zero-crossing detection is performed at the ZC 42, and the detection result becomes the Doppler shift frequency at the observation position. In this way, Doppler shift frequencies at each column of memory addresses, in other words at a plurality of observation positions, are obtained. At this time, if the column readout period is set to 160 μs, the Doppler shift frequency information at one observation position is 160 μs × 64,
In other words, it will be read every 10.24ms.

The Doppler shift frequency information obtained in this way is digitized via the A/D converter 43,
It is input into the memory 44. This memory 44 writes information on the input Doppler shift frequency as a signal obtained by dividing the 400 kHz clock signal by 64 via a frequency divider 45, that is, a 6.25 kHz signal. Thereafter, the Doppler shift frequency information written in the memory 44 is read out at a speed of 400 kHz, converted to an analog signal (amplitude signal) via the D/A converter 46, and then displayed on the display device 47.
The brightness is modulated and displayed. This display device 47 receives the rate signal from the frequency divider 5 and performs sweep scanning, and the brightness-modulated signal is displayed in correspondence with the observed region. That is, the magnitude of the blood flow velocity at each observation site is displayed as brightness information that is luminance-modulated. When displaying the direction of blood flow, for example, a color display cathode ray tube may be used to display the positive direction in red and the negative direction in blue. Alternatively, the output of the RAM 37 may be subjected to fast Fourier transform to be subjected to frequency analysis, and the analysis results may be written directly into the memory 44. Furthermore, the display device 47 may of course display a tomographic image obtained by B-mode scanning together with the blood flow velocity information. Further, it is a matter of course that the scanning direction for the Doppler observation described above may be variably set.

By the way, by synchronizing the above-mentioned Doppler observation with an electrocardiograph or the like, it is possible to perform it over the entire ultrasound diagnostic region. In this way, for example, a tomographic image of the heart can be obtained by B-mode scanning, information on the circulation of blood flowing in the heart can be obtained by Doppler scanning, and the state of change can be displayed moment by moment.

The explanation will be given below with reference to FIG.
RAM37 is similar to the one shown in Figure 9 above, and its output is a digital zero cross meter (DZC).
51 and a Doppler signal is obtained.
This DZC 51 calculates the output of the RAM 37, that is, the number of zero crossings of the above-mentioned sampling value, and calculates the Doppler shift frequency from the result. This Doppler shift frequency is determined by the clock oscillator 52.
The data is supplied to the RAM 53, which is controlled for writing and reading at a frequency of 400 kHz, and is sequentially written to addresses in the RAM 53. Further, the writing timing of the RAM 53 is established in synchronization with, for example, the R wave of an electrocardiograph (ECG) 55 extracted via the waveform shaping circuit 54.

The RAM 53 has, for example, an address structure of (64×64×64) as shown in FIG. When the R wave of the first heartbeat is obtained by the ECG 55, the RAM 53 stores information on the Doppler shift frequency output from the DZC 51 in synchronization with the R wave at addresses "1, 1, 1" and "1". ，
1, 2" to "1, 1, 64" in sequence. In other words, the address "1, 1, 1" of RAM 53 has
RAM37 address “1,1” “2,1” “3,
Information on the Doppler shift frequency obtained from the information from ``1'' to ``64,1'' is written, and in the same way, addresses ``1, 2'' and ``2, 2'' of the RAM 37 are written to addresses ``1, 1, 2''. The Doppler signal obtained from the information "3,2" to "64,2" is written. Then, at the next rate, the Doppler signal obtained from the information read from the RAM 37 is transmitted to the RAM 53 addresses "2, 2, 1""2, 2, 2""2, 2,
3" to "2, 2, 64" in sequence. Furthermore, the address “3,” of RAM53 is set to the next rate.
3,1” “3,3,2” “3,3,3” ~ “3,
3, 64''. and said
When a second heartbeat is detected by ECG55,
This time the address “1, 2, 1” “1, 2, 2” ~
Starting from "1, 2, 64", the address "2,
3,1”, “2,3,2” to “2,3,64”, and “3,4,1”, “3,4,2” to “3,4,6”
4”, and further addresses “64,1,1”, “64,
Doppler shift frequency information is sequentially written from "1, 2" to "64, 1, 64".

In this way, RAM5 is synchronized with 64 heartbeats.
When all Doppler shift frequency information has been written to addresses 3 (64 x 64 x 64), the first area from addresses ``1, 1, 1'' to ``1, 64, 64'' contains heartbeats. The blood flow velocity information indicated by the Doppler shift frequency of the entire diagnostic region in the first state is stored. In addition, the second area from address "2,1,1" to "2,64,64" stores information on blood flow velocity in all diagnostic areas in the second state based on the input timing of heartbeat. be done. Similarly, each memory area of the RAM 53 stores information on the blood flow velocity of all diagnostic areas over time.

Therefore, if the memory area of the RAM 53 is designated according to the state of the tomographic image obtained by B-mode scanning, and the Doppler shift frequency information stored in the same area is read out and displayed, the image will be displayed. This becomes a blood flow velocity information image for the entire diagnostic region corresponding to the displayed tomographic image. When displaying each of the above images on the display device 56, for example, the tomographic image may be brightly modulated and displayed in white, and the blood flow velocities in the positive direction and negative direction may be displayed in red and blue with brightness modulation. Bye.
In this way, for example, it is possible to easily grasp changes in the movement of the heart at the same time, and it is particularly effective in diagnostic medicine of the circulatory system.

Note that the heart does not necessarily move in exactly the same way every heartbeat. Therefore, sufficiently accurate information can be obtained by repeating the above calculation several times and calculating the average. Also, with the above-mentioned conditions, one row address of the RAM 53, for example "1,
If you write the Doppler shift frequency from "1,1" to "1,1,64", the time required is 400μs×
64=25.6ms. Therefore, the Doppler shift frequency of each area of the RAM 53 is determined after a period of 25.6 ms has elapsed. In other words, the information (Doppler shift frequency) stored in the first area is, for example, at time zero, the information in the second area is 25.6ms later, and the information in the third area is 51.2ms later. .
Therefore, the distribution state of blood flow velocity can be read out and displayed as changes every 25.6 ms. Therefore
The signal reading clock frequency from RAM53 is
It only needs to be 160kHz or higher, for example 200kHz,
If a 400kHz clock signal is used, reading can be performed with sufficient margin.

As described above, the present invention provides the following tremendous advantages and effects.

First, by using the only ultrasound probe, it is possible to simultaneously observe real-time tomographic images and blood velocity information due to the Doppler effect. Furthermore, if necessary, an M-mode signal can be obtained from the Doppler effect. Furthermore, since one probe can be used with only one hand, its operability is extremely good, and the tomographic image of the desired position and blood flow velocity information of the necessary parts located within it can be obtained. can be obtained easily. Furthermore, since the two types of diagnostic information described above are obtained using the same probe, the size can be reduced. At the same time, unlike conventional devices, complicated components such as arms, potentiometers, and arithmetic circuits are not required, making it easy to implement. According to the present invention, since the path of the ultrasound beam to obtain the tomographic image and the Doppler shift frequency is the same, errors in the arm, potentiometer, and calculation circuit are caused by differences in sound speed due to differences in the beam path. Blood flow velocity at an accurate position can be detected regardless of the sound velocity without causing any errors, and highly reliable diagnosis can be performed. Furthermore, since the beam path for obtaining the tomographic image and the Doppler shift frequency are the same, it can be confirmed by observing the tomographic image whether or not the beam path for obtaining the Doppler shift frequency has been sufficiently detected. If the position where the Doppler shift frequency is to be detected is depicted in the tomographic image, the Doppler shift frequency at that position can be reliably obtained. Furthermore, since the scanning line used to display the real-time tomographic image can be used to display the area where blood flow information is obtained, a special scanning circuit for displaying the measurement site is not required at all.
Therefore, the circuit configuration including the position detection mechanism and arithmetic circuit can be simplified, and it can be manufactured and realized at low cost. Furthermore, since the reference wave signal and rate pulse use signals from the same reference oscillator, even if the reference oscillator becomes unstable, the phase of the reference wave signal and rate pulse will always remain constant, so the reference wave signal and rate pulse will remain constant. No Doppler shift frequency is generated due to fluctuations between the wave signal and the rate pulse.

Note that the present invention is not limited to the examples. For example, the rate frequency of the ultrasonic signal, the reference oscillation frequency, the frequency of writing to and reading from the memory, etc. may be determined depending on the use. Furthermore, the address structure of the memory and the Doppler shift frequency detection means may be determined as appropriate. Further, in the above embodiments, a sector scan system was described, but a linear scan system may of course be used. Furthermore, in the case of a simple device, blood flow velocity information for the entire diagnostic region may be obtained only two-dimensionally. In short, the invention can be modified and implemented without departing from the gist of the invention.

[Brief explanation of drawings]

Figure 1 is a diagram to explain the problems of conventional equipment.
FIG. 2 is a schematic configuration diagram showing an embodiment of the present invention, FIG. 3 is a signal waveform diagram of each part showing the operation of the device shown in FIG. 2, and FIG. 4 is a diagram showing a repetitive pulse signal.
FIG. 5 is a diagram showing the relationship between the probe and the scanning direction of the ultrasound signal, FIG. 6 is a diagram showing switching between B-mode scanning and Doppler scanning, and the ultrasound signal waveform, and FIG. 7 is a diagram showing the ultrasound signal waveform. FIG. 8 is a signal waveform diagram showing the operation of the device shown in FIG. 7; FIG. 9 is a schematic diagram of the main part showing yet another embodiment of the present invention; 10 is an address configuration diagram of the RAM shown in FIG. 9, FIG. 11 is a schematic configuration diagram of main parts showing yet another embodiment of the present invention, and FIG. 12 is shown in FIG. 11.
FIG. 3 is a RAM address configuration diagram. DESCRIPTION OF SYMBOLS 1... Reference oscillator, 2, 4... Frequency divider (reference frequency), 5... Frequency divider, 7a, 7b, ~, 7n... Delay circuit, 8a, 8b, ~, 8n... Pulser, 9a, 9
b, ~, 9n... Ultrasonic transducer, 11a, 11b,
~, 11n...delay circuit, 12...addition synthesizer, 13
...Detector, 14...Display device, 15, 16...Mixer, 17, 18...Filter, 19...Phase comparator,
20... Range gate circuit, 21, 22... Monostable multivibrator, 23... Filter (BPF), 2
6... Probe (electroacoustic conversion element), 30... Flip-flop, 31... Gate circuit, 32a, 32
b, ~, 32n... Zero crossing detector, 36... Gate circuit, 37... RAM, 39... Clock oscillator, 42
...Zero crossing detector, 44...Memory, 51...Digital zero crossing detector, 53...RAM, 54...Waveform shaping circuit, 56...Electrocardiograph (ECG).

Claims (1)

[Claims] 1 includes a reference signal oscillation unit that oscillates a reference signal, a frequency dividing unit that divides the frequency of this reference signal to generate a rate frequency signal, and a plurality of arrayed ultrasonic transducers, and transmits waves along the scanning direction. A single ultrasonic probe that receives the reflected signal, B-mode scanning that sequentially changes the scanning direction of the ultrasonic probe, and a preset scanning direction of the ultrasonic probe. a scanning unit that alternately and repeatedly performs Doppler scanning according to the rate frequency signal; and a B-mode display that detects a reflected signal obtained by the B-mode scanning and displays it in accordance with the changed scanning direction. a Doppler signal processing section that mixes the reflected signal obtained by the Doppler scanning and the reference signal and obtains a Doppler signal from the difference frequency between the reflected signal and the reference signal; An ultrasound system characterized by comprising: an extraction means for extracting a plurality of Doppler signals from a part of the body in accordance with their generation depth; and a Doppler signal display section for displaying a plurality of Doppler signals extracted by the extraction means. Diagnostic equipment.