JPH02246951A - Ultrasonic diagnostic device - Google Patents

Abstract

PURPOSE:To improve the S/N of a color Doppler to a rate depth direction even when a black dropout, etc., is generated in data by adding respective pixel data of respective rates from a line memory at prescribed times and, further, dividing them at prescribed times. CONSTITUTION:When the data from a timer buffering memory 30 are read to a digital filter 8, data S1 at respective pixel points of respective rates of an ultrasonic raster M are inputted to an adder 41 of an adding circuit 31, pixel data N11, N12 and N 13 in the same rate are successively added by the adder 41, and a pixel counter 42 sends a rest signal S5 to the adder 41 at prescribed times 3 by means of a control signal S3 from a controller 32. Then, an added output N11+N12+N13 is outputted from the adder 41 to a 1/N circuit 43, the division is executed, and a mean output P11 (N11+N12+N13)/3 in a pixel point N1 is obtained. Since one pixel data are prepared in such a way, even when the black dropout of, for example, N12=0, N13=0, etc., are generated, P11 is made into N11/3, and the S/N of the color Doppler can be improved to the rate depth direction.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention provides information on blood flow as functional information accompanying the movement of a moving object within a living body, by utilizing ultrasonic transmission/reception waves and the Doppler effect. The present invention relates to an ultrasonic diagnostic apparatus that obtains images and visualizes them, and particularly relates to an ultrasonic diagnostic apparatus with an improved imaging method.

(Prior art) Ultrasonic diagnostic methods use anatomical information, typically represented by B-mode images, movement information of in-vivo organs, typically represented by M-mode images, and the Doppler effect, typically represented by blood flow imaging. The functional information associated with the movement of moving objects within the living body is used to improve diagnosis.

Further, a typical example of a method of scanning an inside of a living body using ultrasound waves is electronic scanning and mechanical scanning. Here, the electronic scanning method will be explained.

In other words, in the case of linear electronic scanning using an array-type ultrasonic probe (probe) equipped with multiple ultrasonic transducers, a plurality of ultrasonic transducers is regarded as one unit, and this one unit of ultrasonic wave This is a method of transmitting an ultrasonic beam by exciting a vibrator. For example, by sequentially shifting the pitch by one vibrator and excitation so that the position of one unit of element changes one after another, This is a method of electronically shifting the transmission point position of the ultrasound beam.

Then, so that the ultrasound beam is focused as a beam, the excited ultrasound transducers are shifted in excitation timing between those located in the center of the beam and those located on the sides, and the ultrasonic transducers generated thereby The reflected ultrasound waves are focused (electronically focused) using the phase difference between the sound waves generated by the vibrator.

The reflected ultrasound is then received by the same vibrator that was excited and converted into an electrical signal, and the echo information from each transmitted and received wave is formed, for example, as a tomographic image, and the image is displayed on a cathode ray tube or the like.

In addition, in the case of sector scanning, the excitation timing of each transducer is set so that the transmission direction of the ultrasonic beam sequentially changes in a fan shape for each pulse of the ultrasonic beam for one unit of excited ultrasonic transducers. It is changed in accordance with a desired direction, and the subsequent processing is basically the same as the linear electronic scanning described above.

In addition to the above-mentioned linear and sector electronic scanning, there is also mechanical scanning in which a transducer (probe) is attached to a scanning mechanism and ultrasonic scanning is performed by moving the scanning mechanism.

On the other hand, in the imaging method, in addition to a B-mode image in which signals based on ultrasonic transmission and reception are combined to form a tomographic image, an M-mode image based on fixed scanning in the same direction is typical.

This represents the temporal change in the ultrasound transmitting/receiving site, and is particularly suitable for diagnosing moving organs such as the heart.

Further, the ultrasonic Doppler method, of which blood flow imaging is a typical example, is a method of obtaining functional information accompanying the movement of a moving object within a living body and visualizing it, and this will be described in detail below. That is, the ultrasonic Doppler method utilizes the ultrasonic Doppler effect in which when an ultrasonic wave is reflected by a moving object, the frequency of the reflected wave shifts in proportion to the moving speed of the object.

Specifically, if an ultrasonic rate pulse (or continuous wave) is transmitted into a living body and the frequency shift due to the Doppler effect is obtained from the phase change of the reflected wave echo, the Motion information of moving objects can be obtained. According to this, it is possible to know the state of blood flow such as the direction of blood flow at a certain position in the living body, the state of the flow (disturbed or regular), the flow pattern, the velocity value, etc.

Next, the device will be explained. That is, in order to obtain blood flow information from ultrasonic echoes, ultrasonic pulses are repeatedly transmitted a predetermined number of times in a certain predetermined direction, and phase information is extracted by phase-detecting the received echoes. This signal is digitized and passed through a digital filter to remove non-moving or slow-moving components, or clutter components. Then, the signal that has passed through the filter is subjected to frequency analysis.

The frequency analyzed by this is the Doppler shift frequency caused by the movement of a moving object, and can be used alone or superimposed on a B-mode image or M-mode image as two-dimensional blood flow information indicating the direction and velocity of blood flow. indicate.

As described above, the ultrasound transmission system, the B or M mode imaging processing system that obtains B mode image information and processes it in black and white, the blood flow imaging processing system that obtains blood flow velocity information and performs Kalani processing, and these images are The device includes a display system that displays images alone or in a superimposed manner.

(Problems to be Solved by the Invention) Incidentally, in the CFM (color flow mapping) unit for processing color Doppler in the ultrasonic diagnostic apparatus, the phase-detected signal is digitalized by an A/D converter. This signal is stored in a time buffer memory for each ultrasonic raster. Then, by performing filter processing using the digital filter, C
The color S/N of the FM image is obtained.

However, if the data at each pixel point in the ultrasonic raster has black spots, etc. for some reason, the image quality at that pixel point deteriorates, and as a result, the color Doppler S/N deteriorates. There was a problem.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an ultrasonic diagnostic apparatus that improves the S/N of color Doppler and obtains good ultrasonic diagnostic information.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above problems and achieve the objects, the present invention takes the following measures. That is, the present invention transmits and receives ultrasonic waves within the subject, detects Doppler shift signals from the obtained ultrasonic waves, converts this signal digitally, stores it in a line memory, removes clutter with a filter, and detects blood flow. In ultrasonic diagnostic equipment that extracts only Doppler signals and obtains blood flow information,
When reading data from the line memory to the filter, data at each pixel point at each rate transmitted and received multiple times with respect to an ultrasonic raster consisting of a plurality of pixel points is input sequentially from the line memory, and these data are read out from the line memory. an adder that sequentially adds data a predetermined number of times to obtain an addition output; an arithmetic means that includes an averager that divides the addition output from the adder by the predetermined number of times to obtain one pixel data; and control means for adding the data input to the averager the predetermined number of times, averaging the addition output input to the averager, and outputting this average output to the line memory for each pixel.

It also includes means for generating a window function such as Hanning or Hamming and convolving this window function with time-series pixel data in the distance direction, and control means for outputting a convolution output from this means to the line memory. It is something that

Furthermore, when reading data from the line memory to the filter, the data at each pixel point at each rate transmitted and received multiple times with respect to an ultrasonic raster consisting of a plurality of pixel points is input sequentially from the line memory, and these data are read out from the line memory. Comparing and detecting means for sequentially comparing data a predetermined number of times and outputting the maximum data as one pixel data; and comparing the data input to the comparison and detecting means for a predetermined number of times and outputting the maximum data to the line memory for each pixel. and a control means for controlling.

(Effects) By taking such measures, the following effects are achieved. When reading from the line memory, one pixel data is created on average by adding the data of line N pixels a predetermined number of times to each pixel data of each rate from the line memory and dividing by a predetermined number of times. For example, even if there are black spots etc. in the data of a predetermined number of times, a certain amount of signal can be obtained, the S/N of color Doppler can be improved in the rate depth direction, and good ultrasound diagnostic information can be obtained. It will be done.

In addition, since one pixel data is created by convolving each pixel data with a window function such as Hanning or Hamming, noise components of pixel data in areas other than necessary are removed in frequency analysis, narrowing the input frequency band. Therefore, the color Doppler S/N can be improved.

Furthermore, since the maximum data among N pixels is extracted and the maximum data is created as data for that pixel, a large signal S can be obtained and the S/N of color Doppler can be improved.

(Embodiment) FIG. 1 is a schematic block diagram showing an embodiment of an ultrasonic diagnostic apparatus according to the present invention, and FIG. 2 is a diagram showing details of an adding circuit of the ultrasonic diagnostic apparatus shown in FIG. 1. In FIG. 1, a probe 1, a transmitter 2 and a receiver 3 for transmitting and receiving ultrasonic waves are shown.
It has a detector 6 that detects the Doppler shift signal. L.O.
The UR, which consists of a G amplifier 4° and an A/D converter 5, inputs the signal from the receiver 3, obtains B mode image information, and outputs the D S
It is output to C15. Time buffer memory 30 as a line memory that stores data for each line of A/D Humbertau. Digital filter 8. Correlator 9° calculation unit 10
．． Addition circuit 31 as calculation means. 2nd controller 3
The UDI consisting of 2 manually inputs a signal from the detector 6 to obtain blood flow velocity information and outputs it to the DSC 15. S/H circuit 11
．． U consisting of a bandpass filter 12° FFT circuit 14
D2 manually inputs the signal from the detector 6, obtains information on the dispersion σ, and outputs the information to the DSC 15. In addition, ultrasound diagnostic equipment,
DSC 15 for converting scans, color processor ta, display unit 17° controller 18. encoder 19
．． It is equipped with a video tape recorder 20.

FIG. 2 is a diagram showing details of the adder circuit 31.

The addition circuit 31 includes an adder 41. Pixel counter 42°1/N circuit 43. It consists of an output buffer 44.

When the adder 4I reads data for each ultrasonic rask from the time buffer memory 30 to the digital filter 8, the adder 4I selects a plurality of pixel points Nl, N2, . . . shown in FIG. 3, which will be described later.
As shown in FIG. 4, each pixel point (N
il, N12...) (N21°N22-)
(N31. N32-) - The data s1 at . The 1/N circuit 43 as an averager is connected to the adder 41
One pixel data is obtained by dividing the addition output from the predetermined number of times, and this data s2 is outputted to the time buffer memory 30 via the output buffer 44. The pixel counter 42 as a control means inputs the control signal s3 from the second controller 32, thereby adding the data input to the adder 4I by the predetermined number of times, and after counting the predetermined number of times, outputs the reset signal s5. Adder 41
At the same time, the added output input to the front E1/N circuit 43 is averaged, and this average output is sent to the time buffer memory 3.
0 for each pixel.

FIG. 3 is a diagram showing an ultrasonic scan.

As shown in the figure, one ultrasound raster M includes a plurality of pixel points N1. N2..., and one frame is composed of a plurality of ultrasonic rasters...M.... FIG. 4 is a diagram showing the pixel data of each pixel point at each rate when ultrasonic waves are transmitted and received at multiple rates for one ultrasonic raster M. As shown in the example of FIG. 4, pixel data for each rate, for example, Nil, N1
2. N13 is added and averaged a predetermined number of times by the adding circuit 31 (N H+ N 12+ N t3
/3) is obtained as pixel data at pixel point Nil.

Next, the operation of the embodiment configured as described above will be explained. First, the probe 1 is placed on the observation site of the living body, and the transmitter 2
Ultrasonic pulses from the probe 1 are transmitted from the probe 1 while scanning in a fan-like manner as shown in FIG. That is, as shown in FIG. 4, the ultrasonic beam is transmitted multiple times in the depth direction of each pixel. The transmitted ultrasonic pulse is then subjected to a Doppler shift to obtain a time change in each pixel direction, and is received by the receiver 3. receiver 3
The echo signal containing the Doppler shift signal is input to the LOG amplifier 4 and the detector B. The signal input to the LOG amplifier 4 is logarithmically amplified, further converted to a digital signal by the A/D converter 5, and converted to D S as B-mode image information.
Input to C15.

On the other hand, the echo signal input to the wave detector 6 is phase-detected by the wave detector 6, and converted into a digital signal by the A/D converter 7. The digital signal is then stored in a time buffer memory 30. A wastewater-like process is then performed in which data is read out from the time buffer memory 30 to the digital filter 8. That is, data sl at each pixel point of each rate in the ultrasonic raster M is input from the time buffer memory 30 to the adder 41 of the adding circuit 31.

As shown in FIG. 4, pixel data Nil, N12. N13 is sequentially added by the adder 41, and in response to the control signal s3 from the second controller 32, the repixel counter 42 sends out the reset signal S5 to the adder 41 a predetermined number of times 3. Then, the addition output Nll+N12+N13 from the adder 41 becomes 1
/N circuit 43, which divides the average output pH as pixel data at the pixel point Nl (
Nfl+Nf2+Nl3)/3 is obtained. Similarly, the average output P12 (N12+N13+N14)/3 as pixel data at the pixel point N2 is obtained, and the average output at each pixel point at each rate is sequentially determined. These averaged outputs are sent to the time buffer memory 30 via the output buffer 44 for each pixel.

The thus processed data is then passed through a digital filter 8 to the pixels at the same depth, e.g. P 11
．． P12. It is filtered using P 13 . Further, the calculation unit 10 calculates blood flow information, and the DSC 15
Enter.

On the other hand, the signal from the detector B is sampled by the S/H circuit 11, filtered by the bandpass filter 121, and further frequency-converted by the FFT circuit 14 to obtain frequency information at a specific depth position.
It is input to C15. The three pieces of information are scan-converted by the DSC 15, and blood flow information displayed in color on the display unit 17 is obtained by the color processor IB.

According to such an embodiment, when reading from the time buffer memory 30, data for each pixel data of each rate from the time buffer memory 30 is added a predetermined number of times, that is, N pixel data, and further divided by a predetermined number of times. By doing this, one pixel data is created on average, so for example, N12-
Even if there are black spots such as 0, N13-0, the pH is N
11/3, the color Doppler S/N can be improved in the rate depth direction, and good ultrasound diagnostic information can be obtained.

Next, a second embodiment of the present invention will be described.

FIG. 5 is a schematic configuration diagram showing a second embodiment of the present invention, and FIG.
FIG. 7 is a schematic diagram showing the convolution of a window function and input data, FIG. 7 is a schematic diagram showing the window function at each pixel point, and FIG. 8 is a schematic diagram showing various window functions. The present embodiment differs from the first embodiment in that a window function convolution calculation section 35 is provided in place of the addition circuit 31. The window function convolution calculation section 35 has a sixth
As shown in the figure, an FIR filter 51.
A pixel control circuit 52 and a window function control circuit 53 as control means. Window function generator 54 as window function generating means. It is composed of a latch circuit 55.

The FIR filter 51 inputs data sl from the time buffer memory 30 and a window function from a window function generator 54 that generates a window function such as Hanning or Hamming, multiplies them, and outputs the result to a latch circuit 55. It is. The window function control circuit 53 includes the pixel control circuit 5
2 and a control signal s2 from the second controller 32, various window functions shown in FIG. 8 are selected for each pixel, and a selection signal slo is output to the window function generator 54.

According to such a configuration, each pixel data Ni1.
The window function shown in FIG. 8 is selected by the window function control circuit 53 every time N12..., and the selection signal slo is input to the window function generator 54. Then, the selection signal sl
A window function, for example gl (t), corresponding to o is generated, and F
Input to IR filter 51. The FIR filter 51 sequentially inputs pixel data Nil, N12, etc. from the time buffer memory 30 and the window function g.
(t). For example, at pixel Nl, the multiplication output pH-N11*g (t) is performed.

Therefore, since one pixel data is created by convolving each pixel data with a window function such as Hanning or Hamming, noise components of pixel data in areas not necessary for frequency analysis are removed, and the input frequency band can be narrowed. Therefore, the color Doppler S/N can be improved.

Next, a third embodiment of the present invention will be described.

FIG. 9 is a schematic configuration diagram showing the third embodiment of the present invention;
Figure 0 shows the details of the maximum pixel detection circuit of the third embodiment, and Figure 11 shows how ultrasonic waves are transmitted and received at multiple rates for one ultrasonic raster, and each pixel data at each rate is analyzed. FIG. This embodiment differs from the first embodiment in that a maximum pixel detection circuit 37 is provided in place of the addition circuit 31. Maximum pixel detection circuit 37
As shown in FIG. 10, a comparator 45 as comparison detection means, a maximum bit storage circuit 46 . Pixel counter 42 as control means. It consists of an output buffer 44. The comparator 45 as a comparison detection means is
Data at each pixel point is inputted sequentially from the time buffer memory 30 for each rate, and these data are sequentially compared a predetermined number of times, and the maximum data is output as one pixel data. The maximum bit storage circuit 46 stores the comparison data from the comparator 45, outputs this data to the comparator 45, and stores the maximum data as a result of a predetermined number of comparisons. The pixel counter 42a as a control means receives the control signal S3 from the second controller 32, compares the data input to the comparator 45 a predetermined number of times, and outputs a reset signal to the comparator 45 after counting the predetermined number of times. In addition, the maximum bit storage circuit 46. The output buffer 44a is controlled to output the maximum data to the time buffer memory 30 for each pixel.

According to such a configuration, for example, pixel data Nil, N12 . Since the maximum data in N13 is extracted and the maximum data is created as the data for that pixel, even if there are black spots in these pixel data as described above, a certain amount of signal can be obtained and color Doppler It is also possible to improve S/N.

Note that the present invention is not limited to the embodiments described above. It goes without saying that the embodiments described above can be modified in various other ways without departing from the gist of the present invention.

[Effects of the Invention] According to the present invention, when reading from the line memory, data for each pixel data of each rate from the line memory is added a predetermined number of times, that is, data of line N pixels, and further divided by a predetermined number of times. Since one pixel data is created on average by , for example, even if there is a black spot in the data of a predetermined number of times, a certain amount of signal can be obtained, and the S/N of color Doppler can be adjusted in the rate depth direction. can be improved and good ultrasound diagnostic information can be obtained. Furthermore, since one pixel data is created by convolving each pixel data with a window function such as Hanning or Hamming, noise components of pixel data in areas not necessary for frequency analysis are removed, and the input frequency band can be narrowed. Therefore, the color Doppler S/N can be improved. Furthermore, since the maximum data among N pixels is extracted and the maximum data is created as the data for that pixel, a large signal S can be obtained, and an ultrasonic diagnostic apparatus that can also improve the S/N of color Doppler can be provided. .

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram showing an embodiment of an ultrasound diagnostic apparatus according to the present invention, FIG. 2 is a diagram showing an adding circuit, FIG. 3 is a diagram showing an ultrasound scan, and FIG. Figure 5 is a schematic diagram showing the second actual focus example of the present invention, Figure 6 is a diagram showing the window function and the A schematic diagram showing convolution with input data, FIG. 7 is a schematic diagram showing window functions at each pixel point, FIG. 8 is a schematic diagram showing various window functions, and FIG. 9 is a schematic diagram showing the third embodiment of the present invention. A diagram showing the road,
FIG. 11 is a diagram showing pixel data at each pixel point when rate ultrasonic waves are transmitted and received multiple times for one ultrasonic raster. ■...Probe, 2...Transmitter, 3...Receiver, 4
...LOG amplifier, 5,7...A/D converter,
B...Detector, 8...Digital filter, 9...
Correlation unit, 10... Calculation unit, 11... S/H circuit, 1
2...Band pass filter, I4...FF7 circuit,
15...DSC, IS...color processor, 17
...Display unit, 18...Controller, 19...Encoder, 20...Video tape recorder, 30...
- Time buffer memory, 31... Addition circuit, 35... Window function convolution calculation unit, 37... Maximum pixel detection circuit, 41... Adder, 42... Pixel counter, 43... 1/N circuit, 44... Output buffer, 45... Comparator, 4G...-Maximum bit storage circuit, 51... FIR filter, 52... Pixel control circuit, 53... Window function control circuit , 54... window function generator, 55... latch circuit. Applicant's representative Patent attorney Takehiko Suzue Figure 1 Figure 2 Sheet NTI N12 N13 NI4 N+52M 3 rate Nn N+2 N13 N14 NS 3M

Claims (3)

[Claims] (1) Ultrasonic waves are transmitted and received within the subject, a Doppler shift signal is detected from the obtained ultrasound waves, this signal is digitally converted and stored in a line memory, and clutter is removed by a filter to produce a Doppler signal of blood flow. In an ultrasonic diagnostic apparatus that obtains blood flow information by extracting only blood flow information, when reading data from the line memory to the filter, the data of each rate that is transmitted and received multiple times to an ultrasound raster consisting of a plurality of pixel points is used. an adder that sequentially inputs data at each pixel point from the line memory and sequentially adds these data a predetermined number of times to obtain an addition output; an adder that divides the addition output from this adder by the predetermined number of times to obtain one pixel data; an arithmetic means equipped with an averager to obtain the data, and an arithmetic means that adds the data input to the adder of the arithmetic means the predetermined number of times, averages the addition output input to the averager, and stores this average output in the line memory for each pixel. An ultrasonic diagnostic apparatus characterized by comprising: a control means for outputting. (2) Transmitting and receiving ultrasound waves within the subject, detecting Doppler shift signals from the resulting ultrasound waves, converting this signal into digital data, storing it in line memory, removing clutter with a filter, and generating Doppler signals of blood flow. In an ultrasonic diagnostic apparatus that obtains blood flow information by extracting only blood flow information, there is a means for generating a window function such as Hanning or Hamming and convolving this window function with distance direction data, and a convolution output from this means is stored in the line memory. What is claimed is: 1. An ultrasonic diagnostic apparatus characterized by comprising: a control means for causing an output to be output. (3) Transmitting and receiving ultrasound waves within the subject, detecting Doppler shift signals from the resulting ultrasound waves, converting this signal into digital data, storing it in line memory, removing clutter with a filter, and generating Doppler signals of blood flow. In an ultrasonic diagnostic apparatus that obtains blood flow information by extracting only blood flow information, when reading data from the line memory to the filter, the data of each rate that is transmitted and received multiple times to an ultrasound raster consisting of a plurality of pixel points is used. a comparison detection means for sequentially inputting data at each pixel point from the line memory, sequentially comparing these data a predetermined number of times, and outputting the maximum data as one pixel data; An ultrasonic diagnostic apparatus characterized by comprising: control means for comparing and outputting the maximum data to the line memory for each pixel.