JPH08117227A - Ultrasonic diagnostic device - Google Patents

Abstract

PURPOSE: To eliminate an influence of a stationary reflector so as to extract doppler information with higher accuracy by using an aperture synthesis technique adopting the concept of previously invented spatial frequency to overcome the disadvantage of the conventional color doppler. CONSTITUTION: When simply vibrating element groups are driven in order for transmission to obtain a wave front signal and find the spectral distribution, as spectral components by a stationary reflector are mixed, vibrator arrays 1 are driven in the different directions to transmit and receive ultrasonic waves, each data corresponding to the driving order is stored in a wave front memory 10 to be fetched as first and second wave front data in a designated focal point position from the wave front memory 10 by LUT 11, first and second spectral distributions are obtained to take a difference between the distributions. Thus, doppler information caused by a moving reflector, from which an influence of the stationary reflector is removed can be extracted with good accuracy.

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 extracting Doppler information such as a blood flow in a moving reflector, for example, a blood vessel 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 superimposing and displaying the image (B mode image) of ultrasonic reflection is widely used as a color Doppler device. Has been. The principle of measurement of this blood flow velocity is to transmit a pulse wave with a constant cycle by an ultrasonic beam using a transducer array and measure the phase change of the ultrasonic waves returned from a reflector such as blood cells in the living body. , Detect the Doppler frequency. Then, the Doppler frequencies in many spaces are obtained and displayed as a two-dimensional blood flow velocity distribution.

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. .

Since such a conventional color Doppler ultrasonic diagnostic apparatus detects the Doppler effect occurring in the ultrasonic beam direction, the blood flow velocity in the direction orthogonal to the beam is measured. There was an inherent drawback that could not be done.

To obtain a good Doppler signal,
The ultrasonic pulse transmission sequence needs to be performed about 10 times, and it takes a considerable amount of time to update the image to obtain an image of the blood flow distribution, which has a drawback of decreasing the frame rate.

As an ultrasonic diagnostic apparatus for solving such a drawback, the inventor of the present invention disclosed in Japanese Patent Laid-Open No. 11547/1993.
It is proposed in Japanese Patent Publication No. 7. The present invention incorporates the concept of spatial frequency into the aperture synthesis technique and can measure the blood flow in the direction orthogonal to the ultrasonic beam with a high resolution as in the B-mode image without lowering the frame rate. In principle, this is largely different from the color Doppler ultrasonic diagnostic apparatus used.

[0007]

In Japanese Patent Laid-Open No. 5-115477 by the present inventor, transmission / reception is repeated while sequentially switching vibration elements by a multiplexer,
The reflected signal obtained by each vibrating element is stored in the wavefront memory, the wavefront signal corresponding to a given focus is extracted from the collection of reflected signals, the wavefront signal is regarded as a spatial function, and the space distribution is detected by the spectrum distribution detector. The frequency is detected, and the blood flow velocity is obtained from this spectral distribution. In this spectral distribution, a positive frequency component appears when the blood cells approach, a negative frequency component when the blood cells move away, and a reflection signal component of the living tissue that does not move appears as a direct current component of the spatial frequency. Therefore, a B-mode image is created from the DC component, a two-dimensional Doppler distribution image is created from components other than the DC component, the B-mode image is synthesized, and the resulting image is displayed as a color Doppler ultrasonic image.

However, even if the reflector does not move,
It has been found from a later study that a spatial frequency component other than direct current is output when a static reflector is present in another space other than the focus to be synthesized.

This will be described with reference to FIG. 1 is a transducer array, 2-1 to 2-n are oscillating elements, 10 is a wavefront memory, 21 is a wavefront signal sampled so as to correspond to a predetermined focal point, and SI is a real part of the wavefront signal,
SQ represents the imaginary part of the wavefront signal.

FIG. 3A shows a case where the reflector P is in front of the transducer array. When the ultrasonic pulse is transmitted from the vibrating element 2-1, the ultrasonic pulse is reflected by the reflector P,
The reflected signal 22-1 is stored in the wavefront memory 10.
Next, an ultrasonic pulse is transmitted from the vibration element 2-2, and the reflection signal reflected from the reflector P is stored in the wavefront memory 10 as 22-2.

Similarly, all the vibration elements 2-n are transmitted.
Reception is performed and a large number of reflected signals 22-1 to 22-n are obtained. These reflected signals have different signal waveforms because the propagation distances between the vibration element and the reflector P are different.

Here, in order to form a focal point in the space where the reflector P exists in order to provide the directional directivity, the reflected signal 2 is considered in consideration of the round-trip propagation distance between each vibrating element and the focal point.
2-1 to 22-n are sampled at the time points indicated by. The sampled signal becomes the wavefront signal 21 corresponding to the predetermined focus. Further, when sampling, quadrature detection or quadrature sampling is performed to obtain a real part SI and an imaginary part SQ.

The wavefront signal 21 is subjected to a spectral distribution P (f) by a spectral distribution detector such as fast Fourier transform.
Ask for. At this time, since the reflector exists at the position where the focal point is to be formed, the reception signals received by the respective vibrating elements have the same phase during sampling. Therefore, the wavefront signal has only the DC component, and the other spectral components are zero.

Focusing only on this DC component, the "Delay
This is the same as the aperture synthesis technology called “and Sum”.

Next, FIG. 3B shows the case where the reflector P is below the front surface of the focal space (indicated by X) to be synthesized, and how the spatial frequency depends on the wavefront signal and the spectral component. It shows what will happen. In this case, since the distance between the reflector P and the vibrating element 2-n becomes short, the reflected signal 22-n comes to a position closer than that of 22-1. If these reflected signals are sampled at the same time as in FIG. 3 (a) (at the position indicated by the mark), a spatial frequency having a positive frequency component can be obtained.

On the contrary, FIG. 3C shows the case where the reflector P is above the front of the focal space to be combined, and the distance between the reflector P and the vibrating element 2-1 becomes short. Therefore, the reflection signal 22-1 comes to a position closer than that of 22-n. In this case, it has a negative spatial frequency component.

As described in the above three cases, in the space near the focus to be combined, each frequency component of the spectral distribution of the wavefront signal obtained by sampling corresponds to the magnitude of the reflected signal in each direction. To do.

Based on the above description, FIG. 4 shows the positional relationship between the transducer array 1 and the three reflectors Pa, Pb, Pc and the spatial frequency of the spectral distribution. Here, it can be seen that each frequency component of the spectrum distribution indicates the magnitude of the reflected signal in each direction.

For this reason, since the obtained spectral distribution includes the information of the reflection signal of the stationary object other than the focus, the Doppler information based on the movement is simply detected by using the spectral component other than the direct current. It turned out that the result was not enough. That is, a large error may be included due to a defect in the principle of measurement, and there is room for improvement in this respect.

The present invention has been made in view of the above-mentioned circumstances, and an aperture synthesizing technique incorporating the concept of spatial frequency, which was previously invented in order to solve the drawbacks of the conventional color Doppler, was used to create a static reflector. It is an object of the present invention to provide an ultrasonic diagnostic apparatus that eliminates the influence, enhances accuracy, and extracts Doppler information.

[0021]

An ultrasonic diagnostic apparatus of the present invention is an ultrasonic diagnostic apparatus for transmitting and receiving ultrasonic waves to and from an object to be observed in first and second driving orders which are different from each other in a plurality of predetermined directions. Transmitting / receiving means, transmitting / receiving means for outputting an ultrasonic wave excitation signal to the ultrasonic wave transmitting / receiving means, and receiving means for amplifying the reflected signal of the observation target output from the ultrasonic wave transmitting / receiving means. And a wavefront memory for storing the output signal of the receiving unit and storing it as first and second wavefront data corresponding to each direction in which the ultrasonic waves are transmitted and received for each of the first and second driving orders. And a spectral distribution detecting means for obtaining first and second spatial frequency distributions based on the first and second wavefront data from the wavefront data generating means, and a first and second spectral distribution detecting means for obtaining the spectral distribution detecting means. Beauty detects a difference between the second spatial frequency distribution, having a movement speed detection means for calculating a movement velocity of the moving reflector in the observation target.

[0022]

In the configuration of the present invention, if the vibration element groups are simply driven in order to obtain the wavefront signal and the spectral distribution is obtained, the spectral components due to the stationary reflectors are mixed, so that ultrasonic wave transmission / reception is performed. The means transmits and receives ultrasonic waves in different first and second driving orders, and obtains the first and second spatial frequency distributions from the first and second wavefront data corresponding to these driving orders. By taking the difference,
Since the influence of the stationary reflector can be removed, the Doppler information due to only the moving reflector such as blood flow can be accurately extracted.

Therefore, by using the configuration of the present invention, it is possible to display a highly accurate two-dimensional blood flow distribution image.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the principle of the present invention will be described with reference to FIG.

FIG. 2 is an explanatory diagram showing the principle of extracting Doppler information by a moving body by using the aperture synthesis technique which incorporates the concept of spatial frequency.

FIG. 2A shows a case where the transmission driving order of the transducer array 1 is line 1, 2, 3, ..., 7 from the top, which is called sequence A, and the first spectral distribution is detected. This is to explain the process of doing. Here, a state is shown in which the reflector P is approaching the transducer array.

The transmission / reception sequence is line 1 to line 7
Since the spatial distance between the reflector P and the vibrating elements 2-1 to 2-7 gradually becomes shorter, the reflected signals 22-1 to 22-1.
In 22-7, as the line number increases, the arrival time gradually becomes faster than when the reflector is stationary. In the wavefront memory 10, the mark .circleincircle. Is the sampling time for obtaining the wavefront signal forming the focal point.

The wavefront signal 21 obtained by sampling the reflected signals 22-1 to 22-7 becomes an AC signal. When the spectrum distribution is obtained from the wavefront signal 21 by fast Fourier transform or the like, the spectrum PA having a positive spatial frequency is obtained.
(F). In this spectrum PA (f), the spectral component indicated by the broken line is due to the stationary reflector (not shown), while the spectral component indicated by the diagonal line is due to the moving reflector P.

The spectral distribution due to the stationary reflector has various frequency components depending on the distribution of the reflector due to the reasons described above with reference to FIG. 3 or 4.

In FIG. 2B, the transmission drive sequence of the transducer array 1 is opposite to that in FIG. 2A, and lines 7, 6, 5, ...
In the case where it is set to 1, this is referred to as a sequence B, and the process of detecting the second spectral distribution will be described. This sequence B also shows a state in which the reflector P is approaching the transducer array 1. Here, the sequence A
Unlike the driving order of the oscillating element, the reflected signals 22-1 to 22-7 have larger line numbers,
The reflected signal appears to gradually move away. Wavefront memory 1
Wavefront signal 2 if sampled within 0
1 is obtained. This wavefront signal is different from the case of the sequence A shown in (a), and when the spectrum distribution is obtained, a spectrum component having a negative spatial frequency is detected. Here, the negative frequency distribution can be identified because the wavefront signal is handled by a complex number.

The difference between the sequence A and the sequence B in the way of appearance of the spectrum component by the moving body is that the directions of the variable axes of the wavefront signal 21 are opposite to each other.

Further, with a stationary reflector (not shown), the same wavefront signal can be obtained because the reflector does not move for each transmission even if the driving order is changed in the sequence A or B of the transducer array. Therefore, the shape of the spectrum distribution is also the same. If it includes both static and moving reflectors,
Since the linear processing is performed, the component due to the stationary reflector and the component due to the moving reflector are also simply combined in the spectral distribution.

Spectral distribution P obtained in sequence A
Spectral distribution PB obtained by A (f) and sequence B
If the difference calculation PA (f) -PB (f) is performed from (f), the spectral component due to the stationary reflector is eliminated, and FIG.
The difference calculation result shown in (c) is obtained, and only the spectrum component of only the moving body P is output.

If the point symmetric addition PA (f) + PA (-f) is performed from this spectrum with the zero point as the center, the moving body spectrum shown in FIG. 2 (d) is obtained. The frequency of this mobile body spectrum is proportional to the speed of the mobile body, and the magnitude thereof is proportional to the reflection intensity of the mobile body.

As described above, two types of drive sequences for the transducer array 1 are provided, and the difference between the spectral distributions of the wavefront signals obtained by these is taken to eliminate the influence of the stationary reflector and to obtain the information of only the moving body. Can be extracted.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram according to an embodiment of the present invention. 1 is a transducer array, 2-1 to 2-n are oscillating elements, 3 is an ultrasonic pulse wavefront, 4 is a multiplexer for switching transducers, 5 is a pulse generator, 6 is a transmission drive circuit, 7 is reception amplification A circuit, 8 is an STC control circuit for controlling the amplification degree of the reception amplification circuit, 9 is an A / D converter, 10 is a wavefront memory, and 11 is a look for outputting an address of the wavefront memory to extract a wavefront signal of a predetermined focus. Up table (LUT), 12 is a fast Fourier transform circuit (FFT), 13a and 13b are memories for storing the spectral components of the wavefront signal, 14 is a differential circuit for extracting the difference between two spectral components, and 15 is point-symmetrical addition. Circuit, 16 color flow processing circuit, 17a and 17b DC component detection circuit, 18 digital scan converter (DSC), 19 Nita device, 20 denotes a timing control circuit.

In this embodiment, first, as explained in the explanation of the principle, the spectrum distribution of the wavefront signal is obtained in the sequence A. The multiplexer 4 is switched to the vibration element 2-1 under the control of the timing control circuit 20, the pulse generated by the pulse generator 5 is amplified by the transmission drive circuit 6, the vibration element 2-1 is driven, and the ultrasonic pulse 3 is generated. generate. Since this ultrasonic pulse returns as a reflected wave from the living tissue and blood cells, it is amplified by the reception amplification circuit 7 to an appropriate size. At this time, the signal becomes smaller as it is a reflected wave from a long distance, so the amplification degree is increased with time by the control of the STC control circuit 8.

The output of the reception amplification circuit 7 in which the attenuation due to distance is corrected in this way is converted into a digital signal by the A / D converter 9. In order to prevent the information of the input signal band from being damaged, the conversion speed at this time is preferably A / D converted by sampling at a frequency of about 60 MHz when the ultrasonic center frequency is 7.5 MHz. The A / D converted digital signal is stored in the wavefront memory 10 simply as a time-series reflection signal.

Next, the multiplexer 4 is switched to select the vibrating element 2-2, a series of transmission and reception is repeated, and the reflected signals obtained in the same manner are sequentially stored in the wavefront memory 10. All the wavefront data is written in the wavefront memory 10 by performing these processes up to the vibration element 2-n, that is, transmitting and receiving n times.

Next, the look-up table 11 is used to generate an address corresponding to the round-trip propagation distance between the predetermined focus and each vibrating element, and the output of the wavefront memory 10 is sampled to obtain a wavefront signal. Based on this wavefront signal, the fast Fourier transformer FFT12 finds the spectral distribution PA (f) in the sequence A. The spectral distribution at this predetermined focus is subjected to the above processing over the entire space of the observation region, for example, all 256 * 256 pixels, and stored in the memory 13a.

In this way, after performing a series of operations, the processing of the next sequence B is performed. The difference from the case of the sequence A is that the driving order of the vibrator array 1 is the vibration element 2
This is to go from -n to the vibration element 2-1. The spectral distribution PB (f) in the entire image area obtained by this sequence B is stored in the memory 13b. Then, the difference circuit 14 calculates the difference PA (f) between the two spectral distributions.
-PB (f) is calculated and PA is calculated by the point symmetric addition circuit 15.
The mobile body spectrum of (f) + PB (-f) is obtained.

Since the frequency and magnitude of the moving body spectrum are substantially proportional to the blood flow velocity, the color flow processing circuit 14 outputs the Doppler image signal indicating the blood flow generation site. For example, if the moving body spectrum (d) has a positive frequency component, the corresponding part is colored with a warm color system such as red, and if the moving body spectrum (d) has a negative frequency component, a corresponding part with a cold color system such as blue. A Doppler image signal is created so as to color.

On the other hand, the DC component detection circuit 17a extracts only the DC component from the spectrum distribution PA (f) obtained in the sequence A, and the DC component is detected from the spectrum distribution PB (f) similarly obtained in the sequence B. Circuit 17
Only the DC component is extracted by b, and a B-mode image signal representing the strength of the ultrasonic reflection signal is created. A digital scan converter (DSC) 18 performs coordinate conversion and interpolation processing based on the two B-mode signals and the Doppler image signal, and outputs them to the monitor device 19.

The timing control circuit 20 controls the lookup table LUT 11 for switching the selection order of the multiplexer 4 at the timings of the sequence A and the sequence B and for performing aperture synthesis.

According to the present embodiment, the transmission drive order of the transducer array 1 is changed in two ways to obtain the spectral distribution of the wavefront signal, and the difference processing of these spectral distributions is performed, so that only the moving reflector is caused. Doppler information can be detected. In the present embodiment, since the stationary reflector and the moving reflector can be easily separated by the difference processing of the two spectral distributions, an image of the blood flow velocity distribution with high accuracy can be created.

Further, in the present invention, the blood flow distribution image can be obtained in the entire screen without lowering the frame rate in all the spatial regions where the B mode image is obtained.

By the way, in both the sequence A and the sequence B, the spectrum by the stationary reflector is obtained, so that two B-mode images are obtained. Therefore, even if the sequence A and the sequence B are alternately repeated to obtain the Doppler information, the frame rate of the B-mode image does not decrease.

In the above embodiment, the fast Fourier transform circuit is used to detect the frequency distribution at high speed in order to obtain the spectrum distribution of the spatial frequency signal.
A signal processing technique of frequency analysis such as MEM (maximum entropy method) or wavelet transform may be used.

In this embodiment, the oscillator array 1 in which a large number of oscillators are arranged is electronically driven, but waveform data in a plurality of directions can be obtained with respect to the observation target. Since it is sufficient, it may be configured by mechanical scanning, for example.

[Appendix] As described in detail above, according to the embodiment of the present invention, the following constitution can be obtained.
That is, (1) an ultrasonic wave transmitting / receiving means for transmitting / receiving ultrasonic waves to / from an observation target in first and second driving orders different from each other in a plurality of predetermined directions, and to the ultrasonic wave transmitting / receiving means. A transmitting unit that outputs a sound wave excitation signal, a receiving unit that has a receiving unit that amplifies the reflected signal of the observation target output from the ultrasonic wave transmitting and receiving unit, and stores an output signal of the receiving unit, and A wavefront memory that stores as first and second wavefront data corresponding to each direction in which the ultrasonic waves are transmitted and received for each of the first and second driving orders, and the first and first wavefront data from the wavefront data generating means. On the basis of the wavefront data of No. 2, the spectral distribution detecting means for obtaining the first and second spatial frequency distributions, and the difference between the first and second spatial frequency distributions obtained by the spectral distribution detecting means are detected. The ultrasonic diagnostic apparatus having a movement speed detection means for calculating a movement velocity of the moving reflector in the observation target.

In the structure described in Appendix 1, since the stationary reflector and the moving reflector can be easily separated by the difference processing of the two spatial frequency distributions, a highly accurate blood flow velocity distribution image can be created. . Further, by using the configuration described in appendix 1, the blood flow distribution image can be obtained on the entire screen without reducing the frame rate in all the spatial regions where the B mode image is obtained.

(2) The ultrasonic transmission / reception means selects a plurality of ultrasonic transducers for transmitting / receiving ultrasonic waves to / from an observation target and ultrasonic transducers for transmitting / receiving the ultrasonic waves. Means and drive sequence control means for controlling the selecting means to select the ultrasonic transducers in first and second driving orders different from each other, and the transmitting / receiving means via the selecting means. The wavefront memory is connected to the plurality of ultrasonic transducers, and the wavefront memory includes the first and second wavefront memories.
The ultrasonic diagnostic apparatus according to appendix 1, wherein the output signal of the receiving unit is stored as the first and second wavefront data in association with each selected ultrasonic transducer for each driving order.

(3) The selecting means is a multiplexer provided between the transmitting / receiving means and the ultrasonic transducer, and the drive sequence control means is a switching control means for switching the multiplexer. Ultrasonic diagnostic equipment.

(4) The ultrasonic diagnostic apparatus according to appendix 1, wherein the first and second driving orders are predetermined orders.

(5) The plurality of ultrasonic transducers are array transducers in which ultrasonic elements are arranged in an array, and the drive sequence control means sets the array transducer as a first driving order. From the ultrasonic element at one end to the ultrasonic element at the other end in order, and as the second driving order, from the ultrasonic element at the other end of the arrayed transducer to the ultrasonic element at one end in order. The ultrasonic diagnostic apparatus according to appendix 2, which controls the selection unit.

(6) The ultrasonic diagnostic apparatus according to appendix 1, wherein the wavefront memory is storage means for storing the output signal of the receiving section for each ultrasonic transducer in time series.

(7) In the wavefront memory, the synthesized sound field synthesized from the independent sound fields formed by the ultrasonic transducers in the first and second driving orders has a focus at a predetermined position. 7. The ultrasonic diagnostic apparatus according to appendix 6, further comprising memory reading means for reading the stored output signal of the receiving means at each sampling time.

(8) The ultrasonic diagnostic apparatus according to appendix 7, wherein the memory reading means controls so as to change the focus of the synthesized sound field according to the spatial position corresponding to the point to be read in the wavefront memory. apparatus.

(9) In the memory reading means, the synthetic sound field synthesized from the independent sound fields formed by the ultrasonic transducers in the first and second driving orders is the observation region including the observation target. To scan at least one dimension,
7. The ultrasonic diagnostic apparatus according to appendix 6, wherein the output signal of the receiving means stored in the wavefront memory is read at each sampling time.

(10) The ultrasonic diagnostic apparatus according to appendix 1, wherein the spectral distribution detecting means includes a fast Fourier transformer that obtains the first and second spatial frequency distributions by fast Fourier transform.

In the ultrasonic diagnostic apparatus described in Appendix 10, the spatial frequency distribution detection can be processed at high speed by using the fast Fourier transformer.

(11) A low-pass filter means for extracting a DC component from the output of the spectral distribution detection means, and an image memory including a first memory plane for sequentially storing the output of the low-pass filter means. Appendix 1
The ultrasonic diagnostic apparatus according to item 1.

(12) The motion velocity detecting means calculates difference between the first and second spatial frequency distributions, and an output of the difference calculating means is point-symmetrical addition calculation with respect to the origin of the spatial frequency distribution. The ultrasonic diagnostic apparatus according to appendix 1, further comprising addition calculation means for performing the above.

(13) The ultrasonic diagnostic apparatus according to appendix 11, wherein the image memory has a second memory plane for sequentially storing the output of the motion velocity detecting means.

(14) The ultrasonic diagnostic apparatus according to appendix 13, wherein the image memory means has an image superimposing means for superimposing and outputting the respective image information stored in the first and second memory planes.

In the structure described in appendix 14, the data stored in the first memory plane becomes the direct current component of the spatial frequency and simply represents the reflection intensity, and the frequency components other than this direct current component are the second memory. The data stored in the plane, that is, the moving reflector, for example, Doppler data representing a blood flow component, can be combined and displayed as B-mode image data.

(15) Ultrasonic waves are transmitted to the observation target in a predetermined first driving order in a plurality of predetermined directions, reflected waves from the observation target are received in the respective directions, and the received waveforms are received. The spatial frequency distribution of the first wavefront data synthesized from is calculated, and ultrasonic waves are applied to the observation target in a second driving order different from the predetermined first driving order in the predetermined plurality of directions. The spatial frequency distribution of the second wavefront data, which is transmitted, receives the reflected waves from the observation target in each of the directions, and is synthesized from the received waveforms, and calculates the spatial frequency distribution of the first wavefront data and the second Detection method of moving velocity of moving reflector by ultrasonic wave to detect the difference between spatial frequency distribution of wavefront data of the above.

Simply, the vibration element groups are sequentially driven for transmission,
Although the spatial frequency component due to the stationary reflector is mixed only by obtaining the spatial frequency distribution by obtaining the wavefront signal, in the method for detecting the constant velocity of the moving reflector by the ultrasonic wave described in Appendix 15, the space of the first wavefront data is used. By detecting the difference between the frequency distribution and the spatial frequency distribution of the second wavefront data,
It is possible to remove the influence of the stationary reflector and extract Doppler information due to only the moving reflector.

(16) Moving reflection by ultrasonic waves described in appendix 15 for obtaining first wavefront data and second wavefront data by synthesizing reception signals obtained at a predetermined position in a target space. A method for detecting the speed of body movement.

The method for detecting the moving velocity of a moving reflector using ultrasonic waves described in appendix 16 uses an aperture synthesizing technique that incorporates the concept of so-called spatial frequency. The obtained directivity can be sharpened, and from the difference in the spatial frequency distribution obtained from these wavefront data, the Doppler information based on the moving reflector such as blood flow that is not affected by the static reflector and has excellent azimuth resolution can be accurately obtained. You can ask.

(17) After detecting the difference between the spatial frequency distribution of the first wavefront data and the spatial frequency distribution of the second wavefront data, it is obtained as a point object based on the origin of both spatial frequency distributions. 16. The method for detecting the moving velocity of a moving reflector using ultrasonic waves according to appendix 15, which adds the difference values.

(18) To an ultrasonic wave transmitting / receiving means for transmitting / receiving ultrasonic waves to / from an object to be observed in first and second driving orders different from each other in a plurality of predetermined directions, and to the ultrasonic wave transmitting / receiving means. A transmitting unit that outputs an ultrasonic excitation signal, a receiving unit that has a receiving unit that amplifies the reflection signal of the observation target output from the ultrasonic transmitting and receiving unit, and stores an output signal of the receiving unit, Wavefront data acquisition means for obtaining first and second wavefront data forming a predetermined focus of ultrasonic waves transmitted and received in the first and second driving orders based on the output signal, and the wavefront data acquisition Spectrum distribution detecting means for obtaining the first and second spatial frequency distributions based on the first and second wavefront data from the means, and the first distribution obtained by the spectrum distribution detecting means.
And a motion velocity detecting means for detecting a difference between the second spatial frequency distributions and calculating a motion velocity of the motion reflector in the observation target.

(19) The wavefront data acquisition means includes a storage means for storing the output signal of the reception section in time series for each ultrasonic transducer, and a predetermined focus of the data stored in the storage means. 19. The ultrasonic diagnostic apparatus according to appendix 18, comprising addressing means for designating an address of the storage means for extracting as wavefront data.

(20) The motion velocity detecting means calculates a difference between the first and second spatial frequency distributions, and calculates the output of the difference calculating means with respect to the origin of the spatial frequency distribution by point symmetric addition calculation. 19. The ultrasonic diagnostic apparatus according to appendix 18, further comprising: an addition operation unit that performs

(21) The ultrasonic wave transmitting / receiving means is composed of a vibrating element group arranged in an array, and these vibrating element groups are switched by transmitting and driving in two kinds of sequences as the first and second driving orders. The storage means is a memory for storing as a reflection signal corresponding to each element of the vibrating element group, and the addressing means is the memory so as to form a focus according to a propagation distance. Is a look-up table for generating the first and second wavefront data by generating the address data of the first and second wavefront data, wherein the spectral distribution detecting means obtains the first and second wavefront data obtained according to the address generated by the look-up table. It is a spectrum distribution detector that inputs two spatial frequency distributions, and the motion velocity detecting means detects the difference between the two spatial frequency distributions. And ultrasonic diagnostic apparatus according to Appendix 19 to obtain the detecting and the blood flow velocity distribution of the Doppler information due to the moving reflector.

[0076]

As described above, according to the present invention,
By changing the transmission driving order of the ultrasonic wave transmitting / receiving means to two different ways, the spatial frequency distributions of the respective wavefront data are respectively obtained, and the difference processing of these spatial frequency distributions is performed to obtain Doppler information due to only the moving reflector. It has an effect that it can be detected with high accuracy.

[Brief description of drawings]

FIG. 1 is a configuration diagram for explaining an embodiment of the present invention.

FIG. 2 is a conceptual diagram for explaining the principle of the present invention.

FIG. 3 is an explanatory diagram of a correspondence relationship between a position of a reflector and a spectral distribution.

FIG. 4 is an explanatory diagram showing that each frequency component of the spectrum distribution corresponds to a reflection signal in each direction.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Transducer array 2-1 to 2-7 ... Oscillation element 4 ... Multiplexer 7 ... Reception amplification circuit 9 ... A / D converter 10 ... Wavefront memory 11 ... Look-up table (LUT) 12 ... Fast Fourier transformer (FFT) 14 ... Difference circuit 15 ... Point symmetrical addition circuit 17a, 17b ... DC component detection circuit 18 ... Digital scan converter 19 ... Monitor device 20 ... Timing control circuit

Claims (1)

[Claims] 1. An ultrasonic wave transmitting / receiving means for transmitting / receiving ultrasonic waves to / from an observation target in first and second driving orders different from each other in a plurality of predetermined directions, and to the ultrasonic wave transmitting / receiving means. A transmitting unit that outputs a sound wave excitation signal, a receiving unit that has a receiving unit that amplifies the reflection signal of the observation target that is output from the ultrasonic wave transmitting and receiving unit, and stores an output signal of the receiving unit, and A wavefront memory that stores as first and second wavefront data corresponding to each direction in which the ultrasonic waves are transmitted and received for each of the first and second driving orders, and first and second wavefront data from the wavefront data generating means. Based on the wavefront data of No. 2, by detecting a spectral distribution detecting unit for obtaining the first and second spatial frequency distributions, and detecting a difference between the first and second spatial frequency distributions obtained by the spectral distribution detecting unit. Having a movement speed detection means for calculating a movement velocity of the moving reflector in the observation target, an ultrasonic diagnostic apparatus characterized by.