JP2703942B2 - Ultrasound diagnostic equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an ultrasonic diagnostic apparatus that obtains and visualizes blood flow information of a living body.

(Prior Art) In ultrasonic diagnostic methods, anatomical information such as a B-mode image as a typical example, motion information of an organ in a living body such as an M-mode image, and a Doppler effect as a typical example of blood flow imaging The diagnosis is provided using function information and the like associated with the movement of the moving object in the living body using the information.

The ultrasonic Doppler method typified by blood flow imaging (CFM) is a method of obtaining and imaging functional information accompanying the movement of a moving object in a living body, and 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 moving object.

Specifically, when an ultrasonic rate pulse or a continuous wave is transmitted into a living body and a frequency shift due to the Doppler effect is obtained from a phase change of the reflected wave echo, a moving object at a depth position where the echo is obtained is obtained. Exercise information can be obtained. According to this, it is possible to know the blood flow state such as the direction of the blood flow, the flow state of whether it is turbulent or regular, the flow pattern, the absolute value of the velocity, etc. at a certain position in the living body. .

Next, the apparatus will be described. That is, in order to obtain blood flow information from an ultrasonic echo, an ultrasonic pulse is transmitted repeatedly in a predetermined direction a predetermined number of times, and phase information is extracted by phase detection of the received echo. This signal is digitized and passed through a digital filter (also referred to as an "MTI filter") to remove non-moving or slow-moving components (clutter components). Then, the signal passing through this filter is subjected to frequency analysis.

Thereby, the analyzed frequency is a Doppler shift frequency caused by the movement of the moving object, and as a unit or B-mode image or a blood flow information such as a two-dimensional blood flow velocity image indicating the direction and velocity of the blood flow. The display is superimposed on the M-mode image.

By the way, electronic scanning and mechanical scanning are typical examples of the scanning method of an ultrasonic wave in a living body.

The electronic scanning method uses an array type ultrasonic probe in which a plurality of ultrasonic transducers are arranged side by side. In the case of sector electronic scanning, an ultrasonic beam of one unit is vibrated to a group of ultrasonic transducers to be vibrated. This is a method in which the excitation timing of each transducer is changed in accordance with a desired direction so that the transmission direction changes sequentially into a sector every one pulse of the ultrasonic beam.

Further, the mechanical scanning method uses an ultrasonic probe which supports the ultrasonic vibrator so as to be rotatable or swingable, and rotates the ultrasonic vibrator to produce a fan as in the case of the electronic scanning described above. This is a method of forming a scanning region having a shape.

(Problems to be Solved by the Invention) However, in mechanical scanning, since the ultrasonic vibrator rotates continuously, it is impossible to repeatedly transmit and receive ultrasonic waves at the same angle. Therefore, when performing blood flow imaging using the mechanical scanning method, one raster of a blood flow image must be formed using a plurality of data obtained by transmitting and receiving ultrasonic waves having different angles as shown in FIG. In such a system, the rasters (a to d) of the blood flow image as shown in FIG.
The number becomes very small, and a good blood flow image cannot be obtained.

Therefore, the present invention has been made in view of the above circumstances, and the purpose thereof is, even when a mechanical scanning method is used,
An object of the present invention is to provide an ultrasonic diagnostic apparatus capable of obtaining a good blood flow image.

[Means for Solving the Problems] The present invention provides a storage means capable of storing phase detection data of an echo signal and a new phase detection data each time new phase detection data is generated by the progress of ultrasonic scanning. Writing control means for writing data to the storage means; read control means for reading a plurality of data including the latest phase detection data and necessary for forming one raster of a blood flow image from the storage means; Blood flow calculation means for performing a calculation process of blood flow image information using the phase detection data.

(Operation) Every time new phase detection data is generated by the progress of the ultrasonic scan, it is written into the storage means under the control of the writing control means. Then, a plurality of data including the latest data and necessary for forming one raster of the blood flow image is read from the storage unit under the control of the read control unit. The read data is taken into the blood flow calculation means, and the blood flow image information is calculated by this means. Therefore, even when the ultrasonic scan is performed mechanically, the number of rasters of the blood flow image is sufficient, and a good blood flow image can be obtained.

(Examples) Hereinafter, the present invention will be described specifically with reference to examples.

 FIG. 1A shows an embodiment of the present invention.

20 is a mechanical ultrasonic probe (hereinafter “probe”)
The probe 20 includes an ultrasonic vibrator 21 rotatably or swingably supported and an ultrasonic vibrator 21
It has a motor 23 for driving the 21 and a rotary encoder 22 for detecting a rotation angle of the ultrasonic transducer 21.

The probe 20 is a mechanical sector scanning device.
Connected to 24. This mechanical sector scanning device 24
Is a motor controller 29 for controlling the rotation of the motor 23 in the probe 20, and the ultrasonic transducer 21 based on the angle data from the rotary encoder 22 in the probe 20.
And an angle detector 30 for detecting the rotation angle of the camera. The rotation angle detection data from the angle detector 30 is transmitted to the motor controller.
29 and the rate raster address generator 31.
The rate signal generated by the rate raster address generator 31 is taken into the pulser 26. The pulser 26 generates a drive pulse in synchronization with the rate signal. This drive pulse is applied to the ultrasonic vibrator 21, and the ultrasonic echo received by the ultrasonic vibrator 21 is taken into the amplitude detector 28 and the mixers 33a, 33b via the preamplifier 25. It has become. The amplitude detector 28 detects the amplitude of the echo signal received via the preamplifier 25. The detected output is supplied to a DSC (digital scan converter) 43 as B-mode configuration data. Has become. The mixer 33a receives the oscillation output of the oscillator 27 directly, and the mixer 33b receives the oscillation output from the oscillator 27 via the 90 ° phase shifter 32. The mixed output (phase detection output) of the mixers 33a and 33b is output from the low-pass filter 35a,
The data is taken into the MTI calculator 37 via 35b.

The MTI operation unit 37 includes A / D converters 38a and 38b for converting the outputs of the low-pass filters 35a and 35b into digital signals,
MTI filter 40 that removes clutter components from A / D conversion output
a, 40b and based on the outputs of the MTI filters 40a, 40b,
MTI calculator 42 that performs arithmetic processing for blood flow imaging
And The MTI calculator 42 receives a data number (No.), a raster address, and a rate signal. The calculation output of the MTI calculator 42 is taken into the DSC 43 as blood flow image configuration data.

The DSC 43 performs the scan conversion of the B-mode configuration data and the blood flow image configuration data. The scan conversion output by the DSC 43 is output from a color processing circuit arranged at the subsequent stage.
The image data is transferred to a color monitor 46 via a digital-to-analog (D / A) converter 45, where it is visualized.

Next, the detailed configuration of the MTI calculator 42 will be described with reference to FIG. 1 (B).

The MTI calculator 42 includes a write control unit 50, a buffer memory group 51, a read control unit 52, a calculation control unit 58, and a blood flow calculation unit 59.

The buffer memory group 51 stores the outputs of the MTI filters 40a and 40b (this is the phase detection data of the echo signal), and includes eight buffer memories. That is, they are MEM1a to 4a and MEM1b to 4b. Here, the buffer memory group 51 is an example of a storage unit in the present invention. (Note that here, the number of buffer memories is eight for convenience of explanation, but (the number of data of autocorrelation = 4), usually more data, for example, about 10 to 30 data is required). The writing of data into the buffer memory group 51 is controlled by the writing control means 50, and the reading of data from the buffer memory group 51 is controlled by the reading control means 52. The blood flow calculation means 59 performs autocorrelation calculations based on the data read from the buffer memory group 51.
And arithmetic units 54a and 54b for calculating the average velocity, variance, and power of the blood flow from the autocorrelation arithmetic output, and a multiplexer (MUX) 57 for selecting the arithmetic unit output. The data No., the raster address, and the rate signal from the rate / raster address oscillator 31 are taken into the arithmetic control means 58, and the arithmetic control means 58 writes the read control means 50, the read control means 52, The operation of the calculating means 59 is controlled.

Next, the operation of the embodiment device configured as described above will be described.

The motor 23 is rotated under the control of the motor controller 29, whereby the ultrasonic transducer 21 is rotated. This rotation is detected by the rotary encoder 22, and rotation angle detection data is output from the angle detector 30. This detection data is taken into the motor controller 29 and the rate raster address oscillator 31. Then, based on the rate signal from the rate raster address oscillator 31,
A drive pulse is output from 26 and applied to the ultrasonic transducer 21. As a result, the ultrasonic waves are transmitted toward the living body, and the ultrasonic scan is performed by the rotation of the ultrasonic transducer 21. Then, the ultrasonic echo from the living body is taken into the amplitude detector 28 via the preamplifier 25, where the amplitude detection is performed. This amplitude detection output is taken into the DSC 43.

The output (echo signal) of the preamplifier 25 is
a, 33b, where it is phase detected. The phase detection output is taken into low-pass filters 35a and 35b, where the carrier components are removed, and then input to the MTI calculator 42 via the A / D converters 38a and 38b and the MTI filters 40a and 40b.

 Here, the detailed operation of the MTI calculator 42 will be described.

First, data is written to each memory of the buffer memory group 51 under the control of the write control means 50. This data writing is performed in ascending order of the data No. That is,
In FIG. 2, first, data of data No. 0 is written to MEM1a, 1b, then data of data No. 1 is written to MEM2a, 2b, and then data of data No. 2 is written to MEM3a, 3b. Is written to
Then, the data of data No. 3 is written into MEMs 4a and 4b. When the data Nos. 0 to 3 are written, all the data are read under the control of the read control means 52 and input to the autocorrelation calculator 53a. The autocorrelation calculator 53a is
An autocorrelation is obtained from this input data, and the result is calculated by the arithmetic
To send to. Then, the average velocity, variance, and power of the blood flow are obtained by the arithmetic unit 54a. Thus, one raster (a) of the blood flow image is formed.

The ultrasonic scan is progressing even during the above calculation processing, and the data following data No. 3 in FIG.
No.4 data is imported. This data is written to the buffer memory (here, MEM1a, 1b corresponds to this) where the oldest data (here, No. 0 corresponds to this) is currently stored in the buffer memory group 51. That is,
The buffer memory group 51 always stores data of four ultrasonic rasters including the latest data. And
When the data No. 4 is written, all the data in the buffer memory group 51 is read under the control of the read control means 52. This data is taken into the autocorrelation calculator 53b this time. As a result, the autocorrelation calculator 53b calculates the autocorrelation, and the calculator 54b calculates the average velocity, variance, and power of the blood flow, thereby forming one raster (b) of the blood flow image.

In the above case, since the oldest data is replaced with the latest data in the buffer memory group 51, the read control unit 52 rearranges the read data so that the data is arranged in ascending order of data No. Done. As a result, the read data (Da1, Db2), (Da2, Db
2), (Da3, Db3) and (Da4, Db4) are always arranged in ascending order of data No.

Then, in the same manner as above, the new data is
Each time the data is written into the buffer memory group 51 under the control of 50, a plurality of data (here, buffers) including the latest data and necessary to form one raster of the blood flow image are controlled under the control of the read control means 52. (Which means data for four ultrasonic rasters in the memory group 51). That is, data is read for each group indicated by a to m in FIG. Then, the data group is used as an autocorrelation calculator 53a.
And 53b are alternately taken in and subjected to autocorrelation calculation processing. FIG. 3 shows a raster of a blood flow image by the apparatus of this embodiment, and it can be seen that the number of rasters is greatly increased as compared with the case of FIG.

Here, two systems of the autocorrelation calculator and the calculators of the average speed, variance and power are provided for the following reason.

Since the phase detection data is generated one after another by the progress of the ultrasonic scan and is taken into the MTI calculation unit 37, there is a possibility that the autocorrelation calculation and the calculation of the average speed, variance, and power may not be in time for the above data. There is. Therefore, two arithmetic units for performing these arithmetic processes are provided (of course, three or more systems may be provided). Each time data is read from the buffer memory group 51, the arithmetic unit for executing the arithmetic process for the data is different. Thus, the speed of the arithmetic processing as the whole blood flow arithmetic means 59 is increased. Therefore, from MUX57,
The processing result of the computing unit 54a and the processing result of the computing unit 54b are output alternately.

The control of the blood flow calculation processing described above is performed by the calculation control means 58.

When the autocorrelation calculation processing and the calculation processing of the average speed, variance, and power can be performed in time for the above data acquisition, the blood flow calculation means 59 may be formed by one system of calculation units 53a and 53b. In this case, the MUX 57 is unnecessary.

The B-mode configuration data and the blood flow image configuration data obtained in this way are output to the color processing circuit 4 via the DSC 43.
4 and color-processed here, then the D / A converter
The image is transmitted to the color monitor 46 via the display 45 and displayed. The display image on the color monitor 46 is a color blood flow image superimposed on a monochrome B-mode image.

As described above, in the apparatus of this embodiment, the number of rasters of the blood flow image can be increased despite the use of the mechanical scanning method, so that a good blood flow image can be obtained. Further, by increasing or decreasing the number of data required to form one raster of the blood flow image, the image quality can be adjusted to emphasize the frame rate and the speed resolution.

 The present invention is not limited to the above embodiment.

For example, in the above-described embodiment, an example has been described in which ultrasonic scanning is performed mechanically, but ultrasonic scanning may be performed electronically. In this case, since the number of times of transmitting and receiving ultrasonic waves for forming one frame of the blood flow image can be reduced, a blood flow image excellent in real-time performance can be obtained by improving the frame rate.

[Effects of the Invention] As described above in detail, according to the present invention, it is possible to provide an ultrasonic diagnostic apparatus capable of obtaining a good blood flow image even when a mechanical scanning method is used.

[Brief description of the drawings]

1A is a block diagram of an apparatus according to an embodiment of the present invention, FIG. 1B is a detailed block diagram of a main part of FIG. 1A, and FIGS. FIG. 4 and FIG. 5 are explanatory diagrams showing the relationship between the ultrasonic raster and the blood flow image raster in the conventional apparatus, and FIG. 4 and FIG. 20 ... ultrasonic probe, 50 ... writing control means, 51 ... buffer memory group (storage means), 52 ... reading control means, 59 ... blood flow calculation means.

Claims (2)

(57) [Claims] An ultrasonic diagnostic apparatus configured to receive an echo of an ultrasonic wave transmitted toward a living body and obtain a blood flow image of the living body based on a phase detection output of the echo signal.
Storage means for storing phase detection data of the echo signal;
Writing control means for writing new phase detection data to the storage means each time new phase detection data is generated by the progress of the ultrasonic scan; and one of the blood flow images containing the latest phase detection data.
A read control unit that reads a plurality of data required for forming a raster from the storage unit; and a blood flow calculation unit that performs a blood flow image information calculation process using the read phase detection data. Ultrasound diagnostic device. 2. The ultrasonic diagnostic apparatus according to claim 1, further comprising an ultrasonic probe for mechanically executing an ultrasonic scan.