JPH0647043A - Ultrasonic diagnostic system - Google Patents

Abstract

PURPOSE:To execute an exact measurement by deriving a spectral distribution by sampling wave front data obtained by each vibration element by adjusting a time base so as to constitute a focus, executing a movement of a frequency axis, and measuring a blood flow velocity from a Doppler component. CONSTITUTION:This system is provided with a probe 1 having plural vibration elements 2-1 - 2-7 for generating an ultrasonic pulse wave front 3, and by an instruction of a switching control circuit 16, a tip part multiplexer 4, etc., are controlled, each vibration element is driven successively and wave front data based on a reflected wave received by each vibration element is stored in a wave front memory 17. Subsequently, by sampling these wave front data by adjusting a time base so as to constitute a focus, a spectral distribution is derived, a movement of a frequency axis is executed so that a frequency which becomes the maximum value of its output becomes zero, reflection intensity of a tissue is derived from a smaller signal component than a prescribed cut-off frequency, other frequency component is fetched as a Doppler component and a blood flow velocity distribution is measured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic diagnostic apparatus for measuring the velocity distribution of blood flow in a living body using ultrasonic waves.

[0002]

2. Description of the Related Art An ultrasonic diagnostic apparatus for measuring blood flow velocity distribution by utilizing the Doppler effect of ultrasonic waves and displaying it by superimposing it on an image of ultrasonic reflection is called a color Doppler device and is widely used. ing. The principle of measurement of this blood flow velocity distribution is that pulse waves are transmitted at a constant cycle by an ultrasonic beam using an oscillating element array, the time until the reflected wave returns from the reflector is measured, and the frequency change of the received signal is measured. Is detected to measure the position and movement of the reflector. This color Doppler device was initially intended for the circulatory system such as the heart, but recently, due to the large amount of information that Doppler has, it has come to be frequently used for diagnosis of abdominal organs.

[0003]

However, in the conventional color Doppler device, since blood flow in the distance direction is detected by the Doppler effect of the ultrasonic beam, the blood flow component in the direction orthogonal to the beam is detected by the blood flow. There is an inherent problem with not being able to detect speed.

In order to detect weak blood flow information,
In addition to the normal B-mode transmission sequence, a sequence for transmitting a pulse with a large time width dedicated to Doppler is required, and in order to obtain a good Doppler signal, 10
Since averaging operation between sequences is required about B times,
The frame rate drops significantly compared to when in mode,
There is a problem that the spatial resolution is reduced.

In order to solve such conventional problems,
The applicant of the present invention, in Japanese Patent Application No. 3-277805, incorporates the concept of spatial frequency into the aperture synthesis technique to achieve a high spatial resolution similar to that of a B-mode image, and facilitate low-speed blood flow without lowering the frame rate. We propose an ultrasonic diagnostic device that can measure blood flow velocity in the direction parallel to the probe surface.

However, various experiments conducted by the present inventor have revealed that the above-described ultrasonic diagnostic apparatus previously proposed by the applicant of the present invention has the following problems. That is, particularly when trying to observe low-speed blood flow, relative velocity is generated between the ultrasonic probe and the measurement site due to movement or pulsation of the subject's body, etc. Doppler components occur in the surrounding normal tissues, and the entire screen is displayed in red or blue. For this reason, the operator performs the observation by devising the subject to hold his breath, but there is a problem that the subject is burdened with the diagnosis for a long time.

The present invention has been made by paying attention to such problems, and is not affected by the relative speed between the probe and the measurement site due to the pulsation of the subject, and therefore the subject Stable measurement of blood flow information without burdening the
An object of the present invention is to provide an ultrasonic diagnostic apparatus that is appropriately configured to display.

[0008]

In order to achieve the above object, according to the present invention, ultrasonic waves are radiated to a living body from each vibration element of a probe having a plurality of vibration elements arranged, and the reflected wave is emitted. The spatial frequency corresponding to the focal space is obtained from the received signals of these multiple vibration elements by the aperture synthesis method, and the Doppler component of the blood flow signal is detected based on this spatial frequency to measure the blood flow velocity distribution. In the ultrasonic diagnostic apparatus, the maximum level component of the spectral distribution of the spatial frequency is used as a tissue reflection signal, and means for globally shifting the frequency distribution so that the frequency of the tissue reflection signal becomes zero, and the shifted frequency. Means for detecting a high frequency component of the distribution as a blood flow Doppler component, and the blood flow velocity distribution is measured based on the detected blood flow Doppler component.

In a preferred embodiment of the present invention, based on the blood flow velocity distribution, the velocity component at which the blood flow approaches the probe is set to the first element of the three primary colors, and the velocity at which the blood flow moves away from the probe. A two-dimensional flow of blood flow is displayed by hue by making a component correspond to a second element of three primary colors and a velocity component parallel to the arrangement of the transducers of the probe to a third element of three primary colors. To do.

[0010]

In the above structure, the spatial frequency corresponding to the focal space is obtained by the aperture synthesis method, the maximum level component of the spectral distribution of the spatial frequency is used as the tissue reflection signal, and the frequency is adjusted so that the frequency of the tissue reflection signal becomes zero. Shifting the distribution globally eliminates the effect of relative velocity between the probe and the measurement site. Therefore, if the high frequency component of the shifted frequency distribution is detected as the blood flow Doppler component, only the blood flow velocity component can be detected efficiently and even lower blood flow can be detected.

Further, by displaying the two-dimensional velocity component of the blood flow in association with each element of the three primary colors, the running state of the blood flow can be easily grasped.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the structure of the essential part of an embodiment of the present invention. This ultrasonic diagnostic apparatus includes a probe 1 having a plurality of vibrating elements 2-1 to 2-7 that generate an ultrasonic pulse wavefront 3, and a tip multiplexer 4 for switching the vibrating elements 2-1 to 2-7. , Signal generator 6, transmission amplifier 7, reception amplification circuit 8, STC control circuit 9 for controlling the amplification degree of the reception amplification circuit 8, bandpass filter (BPF) 10, 90 degree (π / 2) phase shifter 11, multipliers 12a and 12b, low-pass filter (LPF) 13
a, 13b, A / D converters 14a, 14b, memory multiplexers 15a, 15b, tip multiplexer 4 and memory multiplexers 15a, 15b for switching each transmission.
6, wavefront memory 17, address control circuit 18, fast Fourier transform circuit (FFT) 19, peak power detection circuit 2
0, frequency axis shift circuit 21, discrimination peak detection circuit 22
Equipped with. The wavefront memory 17 includes the vibration elements 2-1 to 2-1.
Corresponding to 2-7, it has real part wavefront memories A1 to A7 and imaginary part wavefront memories B1 to B7.

In this embodiment, first, according to an instruction from the switching control circuit 16, the front end multiplexer 4 and the memory multiplexers 15a and 15b are connected to the vibrating element 2-.
1 and the wavefront memories A1 and A2, and in this state, the output of the signal generator 5 passes through the pulse generation circuit 6, the transmission amplifier 7, and the tip multiplexer 4 and the vibration element 2-.
1 is driven to generate an ultrasonic pulse 3. The reflected waves from the adult tissue and the blood cells due to the ultrasonic pulse 3 are converted into an electric signal by the vibrating element 2-1 and the received signal is supplied to the reception amplification circuit 8 via the tip multiplexer 4 to have an appropriate magnitude. Amplify to. At this time, since the signal becomes smaller as the distance increases, the amplification degree of the reception amplification circuit 8 is changed to STC.
It is increased with time under the control of the control circuit 9.

The output of the reception / amplification circuit 8 is subjected to a BPF 10 to remove excess noise, and then the multipliers 12a, 1 of the next stage.
The signal is supplied to a quadrature detection circuit composed of 2b, LPFs 13a and 13b, and π / 2 phase shifter 11, and the input signal is converted into a complex number signal g (t, x) in the baseband shown by the equation (1). The complex number signals separated into the real number part and the imaginary number part are converted into digital signals by the A / D converters 14a and 14b, respectively, and then the multiplexers 15a and 15b.
Through the real part wavefront memory A1 and the imaginary part wavefront memory B
1 is stored as time series data.

[Equation 1] Here, a (t, x) indicates the real part data, b (t, x) indicates the imaginary part data, and x indicates the spatial position of the vibrating element.

Then, under the control of the switching control circuit 16, the tip multiplexer 4 and the memory multiplexers 15a and 15b are used to move the vibrating element 2-1 to the vibrating element 2-2 and the wavefront memories A1 and B1 to the wavefront memory A.
2, switch to B2, do the same transmission and reception,
The reflection signals from the tissue and blood flow are stored in the wavefront memories A2 and B2 as time series data.

When the wavefront data from all of the vibrating elements 2-1 to 2-7 are stored in the wavefront memory 17 by repeating the above processing, the stored wavefront data is processed by the aperture synthesizing method, and each wave space in each space is processed. Reproduce the ultrasonic reflection image. FIG. 2 is a diagram for explaining the aperture synthesis method.
Reference numeral b is an ultrasonic reflector, 24 is a wavefront memory, and 25 is a result of wavefront synthesis. Here, when the ultrasonic pulse is transmitted from the vibrating element 2-1, the reflectors 23a and 23b are
The ultrasonic pulse is reflected by and is stored in the wavefront memory 24 as the wavefront signal 26-1. Similarly, when an ultrasonic pulse is transmitted from another vibrating element (for example, 2-7),
The wavefront signal (eg, 26-7) is stored in the wavefront memory 24. These wavefront signals 26-1 and 26-7 have different waveforms because the spatial relative positional relationship between the vibrating elements 2-1 and 2-7 and the reflectors 23a and 23b is different.

Therefore, in a certain arbitrary space, if the delay and advance of the propagation time are adjusted and added in the wavefront memory 24 so as to make the focal points by the respective vibration elements 2-1 to 2-7,
Similar to the beam combining by the conventional delay circuit, the directional directivity can be provided. This is generally called “Delay and
It is called “Sum”. If this wavefront to be combined is combined for all spaces, the distribution of reflectors can be obtained.

Here, it should be noted that each vibration element 2
Although the directional characteristics of -1 to 2-7 alone are wide and a sufficient azimuth resolution cannot be obtained, the directional characteristics of the probe main body 1 become sharp and the azimuth resolution is improved by the wavefront synthesis. is there. From a different perspective, this is the same as when using a probe with a large aperture by detecting a wavefront signal while moving a probe with a small aperture in a large space and combining them. The sharp directivity is obtained, which is why it is called aperture synthesis.

Next, the principle of detecting the movement of the reflector will be described with reference to FIG. FIG. 3A shows the case where the reflector 21 is stationary, and a series of time-series data is stored in the wavefront memory 24 by the above-mentioned transmission / reception sequence.
When the waveform of the time-series data is sampled at a sampling point as indicated by a mark 27 with a delay time corresponding to the spatial position of the reflector 23, spatial data at a certain moment as shown by a solid line 28 is obtained. Next, sampling is performed when the phase of the received wave at the intermediate frequency is delayed by 90 degrees, and spatial data as indicated by a broken line 29 is obtained. In this case, the data of the solid line 28 and the data of the broken line 29 can be represented as a complex signal as a pair. This periodic change in the spatial data is called spatial frequency, and in this case, it is almost only the DC component. In order to detect the spatial frequency component of this spatial data, Fourier transform is performed by the FFT 19 shown in FIG.
The spatial spectrum shown in (f) is obtained. This spectrum shows data of one point in a certain space.

FIG. 3B shows the case where the reflector 23 is approaching, and the transmitting / receiving sequence is the vibrating element 2-1.
The distance between the reflector 23 and the vibrating elements 2-1 to 2-7 becomes shorter as the number of vibrating elements changes from 2 to 7 as compared with the case of FIG. The signals are slightly shifted in time. This wavefront data is sampled at the same sampling time (・ mark 27) as in Fig. 3 (a).
, The signal with a periodic component is detected. When this is Fourier transformed by the FFT 19 of FIG. 1, a spatial spectrum having a peak at a positive frequency is obtained.

FIG. 4 is a diagram for explaining the phenomenon in which the wavefront data deviates little by little, and shows a state in which the reflector 23 is gradually approaching the vibrating element 2 from the top. As the distance between the reflector 23 and the vibrating element 2 becomes shorter, the received wave arrives earlier. Therefore, if sampling is performed at a certain time, the state of movement of the reflector 23 appears as a change in phase. Therefore, if this sampling is performed at two locations where the phases differ by 90 degrees, it can be represented as a complex signal.

In FIG. 3C, the reflector 23 has the vibrating element array (2-
1 to 2-7), that is, the case of moving in a direction orthogonal to the ultrasonic beam direction. When the reflector 23 moves in the direction of the arrow from the state of FIG. 3 (c), the transmission / reception sequence changes from the vibration element 2-1 to the vibration element 2-.
Up to 3, the spatial distance decreases with the movement of the reflector 23, but in the transmission / reception sequence from the vibrating element 2-4 to the vibrating element 2-7, the spatial distance increases with the movement of the reflector 23. Therefore, when sampling is performed at the same time as in the case of FIG. 3A, signal components having positive and negative frequency components are detected. These positive and negative frequency components can be distinguished from each other by the complex numbered sampling data. Therefore, if Fourier transform is performed by the FFT 19 of FIG. 1 based on this data, a spectrum having both positive and negative components is obtained. Can be detected.

When the reflector 23 is moved away from the vibrating element array, it is the opposite of the case of FIG. 3B, and as a result of the Fourier transform, a negative spectral component is detected. Further, when the reflector 23 moves in the direction opposite to that in the case of FIG. 3C in parallel with the vibrating element array, the phase spectrum which is the output of the Fourier transform is different from that in the case of FIG. Can be detected.

In the above description, in order to make it easy to understand, in order to detect the complex signal which constitutes the reflection signal of a certain focus,
Although sampling is performed when the phase is relatively shifted by 90 degrees, in order to obtain a complex signal, the input signal is multiplied by the multipliers 12a and 12b, the LPF 13a, and the like as shown in FIG.
It is general to detect a complex signal with a circuit configuration using 13b and the π / 2 phase shifter 11.

FIG. 5 conceptually illustrates how the directional characteristics of the ultrasonic beam are changed by wavefront synthesis of the aperture synthesis method. (A) is a frontal direction, and (b) and (c) are left and right. It shows the case where the directional characteristic is created in the direction of. Reference numerals 30a, 30b and 30c are phased wave fronts indicating the times for sampling the data. Also, 31
Reference numerals a, 31b, and 31c are memories for storing sampling data according to the distance, and in this figure, the memories are prepared according to the number of phased wave fronts, but the number is actually larger. By varying the phased wavefront in the memory 24 in this way, it is possible to obtain a directional characteristic in an arbitrary direction.

In this embodiment, the address control circuit 18 shown in FIG. 1 controls the address of the wavefront memory 17 to obtain the above-mentioned phased wavefront, and the reflected image reproduction processing is performed based on the wavefront data. That is, the vibration element 2 is added to the wavefront memory 17.
When all the wavefront data corresponding to -1 to 2-7 are stored, the address control circuit 18 adjusts the time axis so as to form a phased wavefront in a certain direction, and controls the address of the wavefront memory 17. The wavefront data g of the phased wavefront
Read (x). This wavefront data g (x) is FFT19
The spectrum distribution G (w) indicating the spatial frequency is obtained by the following equation.

[Equation 2] Where L is the array length of the vibrating element, P (w)
Indicates the power spectrum and θ (w) indicates the phase spectrum.

As is apparent from the above description, the wavefront data g (x) includes the real part data A1 to A7 (a (x)),
Since it is divided into imaginary part data B1 to B7 (b (x)), the real part data A of this spectral distribution G (w) is obtained by obtaining the spectral distribution G (w) by the FFT 19.
From (w) and the imaginary part data B (w), the power spectrum P (w) and the phase spectrum θ (w) can be obtained based on the above equations (4) and (5).

In FIG. 1, the FFT 19 provides an output having a spectral distribution in which a reflection signal from tissue (clutter component) and a reflection signal from blood flow overlap. Here, when the relative velocity between the target tissue and the probe is zero, the direct current component is always dominant in the reflection signal from the stationary tissue as shown in FIG. Therefore, when the probe moves, a relative velocity is generated between the probe and the stationary tissue, so that the frequency axis shifts by the Doppler frequency corresponding to the relative velocity, as shown in FIG. 6 (b). Further, the magnitude of the reflected signal from the blood flow is smaller than the reflected signal (clutter component) from the tissue by about 40 dB to 50 dB,
The maximum value of the spectral distribution output from the FFT 19 is always the tissue reflection component.

For this reason, when the cutoff frequency f _c shown by the alternate long and short dash line in the figure is used as a boundary, and a value more than f _c is output as a blood flow component, it is preferable that the probe shown in FIG. 6 (a) is stationary. But,
When the probe shown in FIG. 6 (b) is moving, most of the tissue reflection component is regarded as blood flow, which gives rise to a problem that incorrect blood flow information is given.

Therefore, in this embodiment, first, the peak detection circuit 20 detects the frequency f _{0 at} which the level of the spectrum distribution becomes maximum. Here, since the signal component having the frequency f ₀ always corresponds to the reflection signal from the tissue, this frequency becomes the Doppler component generated by the movement of the probe. Next, in order to eliminate the influence of the movement of the probe, the frequency axis shift circuit 21 moves the entire spectrum distribution so that this frequency shift f ₀ becomes zero, as shown in FIG. 6 (C). To correct.

The frequency f at which the clutter component is maximum
_{In order} to detect ₀ , each space in which the focal point is formed by wave field synthesis may be targeted, but in order to detect the frequency f ₀ more stably, the frequency spectrum components obtained in each space in the same direction are used. After taking the average in the distance direction, it is better to find the frequency at which the spectral component becomes maximum. This makes it possible to take advantage of the phenomenon that the relative velocity generated by the movement of the probe main body is the same for each sound ray direction.

Next, the spectrum distribution output corrected by the frequency axis shift circuit 21 is supplied to the discrimination peak detection circuit 22.
To the cutoff frequency f _c as a boundary, and a component having a frequency lower than f _c as a signal component of the B-mode image is
The frequency components above _c are extracted as Doppler signal components corresponding to the movement of blood flow. In this way, FFT1
The peak detection circuit 20 detects the frequency f _{0 at} which the level of the spectrum distribution is maximum from the output of 9 and outputs the frequency f _0.
If the spectrum distribution is corrected by the frequency axis shift circuit 21 so that the frequency becomes zero, the discrimination peak detection circuit 22 simply discriminates the frequency difference between the B-mode image signal component and the Doppler signal component at the cutoff frequency f _c. It is possible to do this, without attenuating the blood flow signal component,
It is possible to detect a good quality Doppler signal that does not include a tissue reflection component.

In order to detect the Doppler frequency from the blood flow signal component extracted as described above, the average frequency fd can be obtained from the spectral component using, for example, the following equation.

[Equation 3]

Actually, since the blood flow has a two-dimensional velocity component, the power spectrum distribution P (W) and the phase spectrum θ (W) have various patterns as described in FIG. , The velocity component in the direction of array of the vibrating elements is detected from the symmetry of the plus and minus frequency components of the spectral distribution.

In this embodiment, in accordance with the velocity component of the blood flow thus detected, that is, the size and direction of the blood flow, for example, as shown in FIG. The frequency component) is red, the distant flow (frequency component of-) is blue, and the flow parallel to the vibrating element array (+ and-)
Frequency component) is colored corresponding to green, and after being image-processed by a digital scan converter or the like, these signals are respectively supplied to the RGB input terminals of the color monitor to be superimposed and displayed on the B-mode image. . By doing so, although the ambiguity in the left-right direction remains, the two-dimensional flow of the blood flow can be expressed as a change in hue.

In the above-mentioned embodiment, the number of vibrating elements of the probe is seven, but in actuality, the transducer is constructed with a larger number of vibrating elements (eg, about 64). . In this way, if the number of vibrating elements is increased, the beam directivity characteristic becomes sharper, so that the spatial resolution can be improved. Also, since the time required for the entire transmission / reception sequence to create a reflection image of a certain point becomes long,
Along with being able to detect the slow movement of blood cells,
As the number of transmission / reception sequences increases, the number of data items also increases, so that the Doppler measurement accuracy can be improved.

Further, the array of the vibrating elements is not limited to the linear array, but may be a circumferential array or an array array array called a convex, which is a midpoint between the linear array and the circumferential array. When the arrangement of the vibrating elements is changed in this way, the address control circuit 18 of FIG. 1 may perform wavefront matching by time adjustment so that the vibrating element arrangement forms a desired focus. Further, in the above-mentioned embodiment,
Although the spectrum of the spatial frequency is obtained by using FFT, the spectrum distribution can be obtained by using a method such as maximum entropy.

FIG. 8 shows an embodiment using a circumferential array vibration element. In this embodiment, a circular array of probes 1-is provided at the tip of a probe of an ultrasonic endoscope to be inserted into a body cavity.
1 is attached, and this is radially scanned around the probe to observe, for example, the cross section of the stomach wall 32 from the inside of the stomach 33, which is the same as in FIG. 1 except that the arrangement of the vibration elements is different. In such an ultrasonic endoscope, it is difficult to fix the tip of the probe, and it is difficult to prevent the tip from swaying.

FIG. 8 shows a state in which the probe 1-1 is moving from the position shown by the broken line to the position shown by the solid line. In this case, a positive Doppler component is generated in the portion [A] and a negative Doppler component is generated in the portion [B] due to the relationship of the relative speed. 9 (a) and 9 (b) show this state using the relationship of the frequency spectra. FIG. 9 (a) shows the frequency spectrum of the site [A], and FIG. 9 (b) shows the site [B]. 2 shows the frequency spectrum of Figure 9
In (a) and (b), the broken line shows the frequency spectrum before the movement of the probe 1-1 is corrected, and the solid line shows the corrected frequency spectrum. What is characteristic here is that the Doppler components of the clutter components generated in a certain sound ray and the opposite sound ray of the probe 1-1 have the same magnitude but different signs.

Therefore, if the motion of the probe 1-1 is corrected for sound rays in all directions in the same manner as described with reference to the configuration of FIG. 1, the motion of the probe 1-1 at the tip end is oscillated. It is possible to obtain a frequency spectrum irrelevant to the above, and finally to detect the Doppler component corresponding to only the blood flow.

[0041]

As described above, according to the present invention, the wavefront data obtained for each vibrating element is stored in the memory, and these wavefront data are sampled by adjusting the time axis so as to form the focal point. The spectrum distribution is obtained by moving the frequency axis so that the maximum frequency of the output becomes zero, and the reflection intensity of the tissue is obtained from the signal component smaller than the predetermined cutoff frequency. Since the component is extracted as the Doppler component, the blood flow velocity can always be detected accurately without being affected by the movement of the probe.

Further, the reflection signal from the tissue and the blood flow velocity signal component can be separated simply by using the cutoff frequency as a boundary by moving the frequency axis of the spectral distribution. Since the cut-off frequency can be remarkably reduced by correcting the movement of, the extremely small blood flow velocity can be accurately detected without attenuating the Doppler frequency component.

Further, the blood flow velocity can be detected not only in the blood flow component in the sound ray direction but also in the direction orthogonal to the sound ray (direction parallel to the array of transducer elements) from the pattern of the spectral distribution of the spatial frequency. At the same time, it is possible to easily grasp the running state of the blood vessel by coloring the blood flow velocity based on the two-dimensional blood flow rate so as to correspond to the color display and superimposing it on the B-mode image showing the reflection intensity of the tissue. be able to.

As described above, according to the present invention, a blood flow having a low flow velocity can be measured and a blood flow parallel to the vibrating element array (parallel to the vibrating surface of the probe) can be measured. Very useful for diagnosis.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is a diagram for explaining the concept of aperture synthesis.

FIG. 3 is a diagram for explaining the principle of detecting the movement of a reflector.

FIG. 4 is a diagram for explaining that the phase wavefront is displaced due to the movement of a reflector.

FIG. 5 is a diagram for explaining the concept of changing directional characteristics.

FIG. 6 is a diagram for explaining motion compensation of a probe.

FIG. 7 is a diagram for explaining colored display according to the velocity direction of blood flow.

FIG. 8 is a diagram for explaining motion correction of a probe having a circumferentially arrayed vibrating element inserted into the stomach.

9 is a diagram for explaining a frequency spectrum of each part generated in the circumferentially arrayed vibrating element of FIG. 8;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Probe main body 2-1 to 2-7 Vibrating element 4 Tip part multiplexer 8 Reception amplification circuit 11 90 degree phase shifter 12a, 12b Multiplier 13a, 13b Low pass filter (LPF) 14a, 14b A / D converter 15a, 15b Memory multiplexer 17 Wavefront memory 18 Address control circuit 19 Fast Fourier Transform (FFT) 20 Peak power detection circuit 21 Frequency axis shift circuit 22 Discrimination peak detection circuit

Claims (2)

[Claims] 1. An ultrasonic wave is radiated from each of the vibrating elements of a probe having a plurality of vibrating elements arrayed to a living body to receive a reflected wave thereof, and an opening is made from the received signals of the plurality of vibrating elements. Obtaining the spatial frequency corresponding to the focus space by the synthesis method, in the ultrasonic diagnostic apparatus to measure the blood flow velocity distribution by detecting the Doppler component of the blood flow signal based on this spatial frequency, the maximum of the spectral distribution of the spatial frequency A level component as a tissue reflection signal, means for entirely shifting the frequency distribution so that the frequency of the tissue reflection signal is zero, and means for detecting a high frequency component of this shifted frequency distribution as a blood flow Doppler component And an ultrasonic diagnostic apparatus configured to measure the blood flow velocity distribution based on the detected blood flow Doppler component. 2. Based on the blood flow velocity distribution, the velocity component of blood flow approaching the probe is the first element of the three primary colors, and the velocity component of blood flow moving away from the probe is the third component of the three primary colors. It is configured to display a two-dimensional flow of blood flow by hue by making two elements correspond to velocity elements parallel to the array of the transducer elements of the probe to the third elements of the three primary colors. The ultrasonic diagnostic apparatus according to claim 1, which is characterized in that.