JP3028163B2 - Doppler CFM ultrasound system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to Doppler CFM (Color F
More specifically, the present invention relates to a Doppler CFM ultrasonic diagnostic apparatus having improved operability of setting a sampling position.

[0002]

2. Description of the Related Art When an object is irradiated with ultrasonic waves, the ultrasonic waves are transmitted using a living tissue as a medium. However, there is a difference in acoustic impedance between the tissue such as an organ or a surrounding tissue such as a lesion. A part of the transmitted ultrasonic wave is reflected back. If the reflector is an object that moves or moves in the line of sight, the frequency of the reflected wave shifts from the transmission frequency due to the Doppler effect. The ultrasonic Doppler diagnostic device is a device that measures the frequency shift amount, displays and observes the speed and moving direction of the moving object, and uses the result for diagnosis.

When the reflector is moving toward the probe, the reception frequency is higher than the transmission frequency, and conversely, lower when the reflector is moving away. And the shift frequency is proportional to the movement speed of the reflector. By utilizing the Doppler effect, for example, the direction and speed of the blood flow flowing through the heart and blood vessels can be known.

In the FFT Doppler method, data on the direction and speed of blood flow at a specific point is obtained by precisely measuring the shift frequency. Then, in order to obtain data from this specific point, select a sound ray with the cursor and gate to the depth you want to detect (sample gate)
To extract a Doppler signal at a specific point.

[0005] By the way, the reflection of the ultrasonic pulse includes a mixture of a reflection by a fixed object and a reflection by a moving object.
In particular, when paying attention to a moving object, it is easier to see the reflected signal of the moving object by erasing the reflected signal of the fixed object, and therefore, for that purpose, an MTI (Moving Target Indicator) that extracts only the reflected signal of the moving object is used. ) Is used.

[0006] However, information on a fixed reflecting object also has important significance in a medical ultrasonic diagnostic apparatus. It is difficult to identify where in the display screen what is represented without the above information, and it is difficult to determine what the moving object is simply by displaying the moving object. Therefore, the display of the fixed object and the display of the moving object are commonly displayed on the same screen, and in order to distinguish them from each other, the direction of the blood flow, the average velocity, the velocity dispersion value, and the power value are obtained from the scattered echoes from the blood cells. Are calculated, and their various amounts are displayed two-dimensionally on the B-mode screen in real time in color. This mode is called a CFM mode, and an apparatus having these functions is a Doppler CFM ultrasonic diagnostic apparatus.

In this apparatus, to obtain blood flow data at a specific point, a procedure as shown in FIG. 6 is performed. In the figure, column A shows an image on the CRT screen,
The columns are a flow chart of the procedure.

Step 1 First, a blood flow distribution is searched for in the CFM mode. This condition is shown in FIG. In the figure, reference numeral 1 denotes a CFM area that appears when the CFM mode is set. The CFM area 1 is drawn so as to be superimposed on a fan-shaped B-mode image. The CFM area 1 is moved up, down, right, left and left to search for a color-displayed portion having a blood flow distribution. As shown, CFM is 2
Because of the dimensional display, it is possible to easily find the place where the blood flow exists.

Step 2 Since a part with blood flow was found, the Doppler component was
To operate the FFT Doppler mode to obtain accurate data by analysis. Row A (b) As shown in the figure, CFM
A cursor 2 and a sample volume 3 passing through a certain position of the area 1 appear. In the CFM area 1 of the blood vessel 4, a colored blood flow display section 5 is displayed.

Step 3 The position of the sample volume 3 is moved to the position of the blood flow display section 5 by input means such as a trackball. Thus, a Doppler image 6 based on the blood flow at the position of the sampling volume 3 is obtained as shown in the column A (d). In the figure, a case where the upper side approaches the center line and a case where the lower side moves away from the center line are shown.

[0011]

In such a conventional Doppler CFM ultrasonic diagnostic apparatus, first, a blood flow position is obtained in the CFM mode, the FFT Doppler mode is operated, and then the sample volume is moved to the blood flow position. I had to move and the operation was troublesome.

An object of the present invention is to provide a Doppler CFM ultrasonic diagnostic apparatus capable of eliminating the operation of moving the sampling volume after switching from the CFM mode to the FFT Doppler mode. It is to realize.

[0013]

A CFM data analysis means for analyzing a received signal to obtain blood flow distribution data including a blood flow velocity, a velocity variance value or a power value, and a Doppler shift by a blood flow of a predetermined sample volume. FF for frequency analysis of
T Doppler analysis means; and data area search means for finding a specific area based on one or more combinations of blood flow velocity, velocity variance value, and power value of the blood flow distribution data, A specific area obtained by the search means is set as a sample volume to be subjected to the FFT Doppler analysis means.

[0014]

The CFM data analyzing means analyzes and obtains blood flow velocity, velocity dispersion value and power value blood flow distribution data.
Input to the data area search means. In the data area search means, one of the given blood flow velocity, velocity dispersion value and power value
An area determined by one or a plurality of combinations is obtained, and the data is provided to the FFT Doppler analysis means. FF
The T-Doppler analysis means frequency-analyzes the Doppler shift of the blood flow in the input area and outputs it as Doppler display data.

[0015]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram of an apparatus according to an embodiment of the present invention, and FIG. 2 is a block diagram showing a schematic configuration of a Doppler CFM ultrasonic diagnostic apparatus including the apparatus of the embodiment.

In FIG. 2, reference numeral 11 denotes a probe for transmitting and receiving an ultrasonic wave, and 12 denotes an amplifier for amplifying an input transmission signal and transmitting the amplified signal to the probe 11 and receiving the signal transmitted from the probe 11. A transmission / reception circuit that amplifies a wave signal controls the destination of a transmitted / received signal.

Reference numeral 13 denotes a reception beamformer that performs phasing addition of the reception signal to generate a serial signal. This output signal is input to the B-mode circuit 14 and subjected to processing such as detection and amplification, and then to the B-mode unit 16 of the DSC 15. The B-mode unit 16 temporarily stores the input signal in the frame memory,
Convert to a signal format for television display.

Reference numeral 17 denotes an FFT Doppler analysis circuit which performs quadrature detection of a received signal input from the received beam former 13, performs a filtering process, selects a blood flow by a sampling volume, performs AD conversion, and performs frequency analysis by FFT processing. The output is input to the Doppler unit 18 of the DSC 15 and stored in the frame memory.
The signal is a television display signal with the vertical axis representing the frequency axis.

Reference numeral 19 denotes a CFM analysis circuit which performs quadrature detection on the received signal input from the received beam former 13 and performs an operation after MTI filtering to output an average speed, a speed dispersion value, and a power value. Is the CFM part 2 of DSC15
Input to 0.

The CFM unit 20 is a circuit having the configuration shown in the embodiment of FIG. 1, and the details of the circuit configuration and operation will be described later. Reference numeral 21 denotes a video unit for generating a synchronizing signal or a sweep signal and displaying signals input from the B-mode unit 16, the Doppler unit 18 and the CFM unit 20 on a display unit 23, under the control of the main control CPU 22. The output of each unit is output alone or in combination. This output signal is displayed on the display device 23.

The main control CPU 22 controls the operation of each circuit in addition to the above control. Next, an outline of the operation of the above-described device will be described. The transmission / reception circuit 12 sends the input transmission signal to the probe 11 after amplification. The probe 11 converts an input electric signal into an ultrasonic signal and transmits the ultrasonic signal into the subject. The transmitted signal is reflected from a reflector in the subject, a part of which is returned to the probe 11 and received, converted into an electric signal, and input to the transmission / reception circuit 12.

The received signal is amplified by the transmission / reception circuit 12, phased and added by the reception beam former 13, and input to the B-mode circuit 14, the FFT Doppler analysis circuit 17 and the CFM analysis circuit 19. The main control CPU 22 controls which of these circuits performs the signal processing.

In the B-mode circuit 14, the input signal is amplified, detected, and input to the B-mode section 16 of the DSC 15. The B-mode unit 16 stores the input signal once, reads it out in the form of a signal for television display, and inputs it to the video unit 21.

In the FFT Doppler analysis circuit 17, after demodulating the input signal by quadrature detection, a gate is applied to a portion selected by a sampling volume, a Doppler signal having a depth on the selected sound ray is taken out, and frequency analysis is performed by FFT.
This frequency signal is input to the Doppler unit 18 of the DSC 15. The Doppler unit 18 stores the input signal in a frame memory, reads out the signal as a television display format signal having time on the horizontal axis and frequency on the vertical axis, and inputs the signal to the video unit 21.

In the CFM analysis circuit 19, the input signal is subjected to quadrature detection, and only the reflection signal from the moving part is selected by the MTI filter. Then, the average speed, the speed dispersion value and the power value are determined by, for example, the autocorrelation method. Under the control of the main control CPU 22, the signal is converted into a single signal or a required combination of signals, input to the CFM unit 20 of the DSC 15, and sent to the video unit 21 after signal processing.

The video section 21 generates a synchronization signal, a sweep signal, and the like, and causes the display device 23 to display the input signal. Next, a detailed circuit configuration of the CFM unit 20 is shown in FIG. In the figure, the same parts as those in FIG. 2 are denoted by the same reference numerals. In the figure, reference numeral 31 denotes a CF to which CFM data obtained by analysis by the CFM analysis circuit 19 is input and stored for each sound ray.
M sound ray memory.

Reference numeral 32 receives a detection command including a detection algorithm from the main control CPU 22 and analyzes and sorts CFM data read from the CFM sound ray memory 31 by a read address from the read address generator 33. It is a CFM stream filter. The data to be selected is, for example, data in a commanded range such as a flow velocity of ○ m / sec or more, or a power value of XX or more.
The CFM stream filter 32 recognizes the address of the data selected in this way in the CFM sound ray memory 31 by the read address that is input simultaneously with the input to the CFM sound ray memory 31, and outputs the address. I do.

The CFM data from the CFM sound ray memory 31 is also input to the video section 21 and displayed on the display device 23. The address from the CFM stream filter 32 is input to the main control CPU 22.

Next, the operation of the circuit configured as described above will be described. Blood flow velocity obtained by the CFM analysis circuit 19,
The CFM data of the velocity dispersion value and the power value are stored in the CFM sound ray memory 31. The CFM data is read by the read address from the read address generator 33, and is input to the CFM stream filter 32 and the video unit 21 of the DSC 15.

A detection command from the main control CPU 22 is input to the CFM stream filter 32 together with an algorithm for setting a range for selecting CFM data and a selection condition, and the CFM stream filter 32
Data in a specified range is selected from the M data, or is calculated by an algorithm and selected.

The read address from the read address generator 33 is input to the CFM stream filter 32, and outputs the address where the selected CFM data is stored to the main control CPU 22.

The main control CPU 22 sends the input address to the FFT Doppler analysis circuit 17. Based on the input address, the FFT Doppler analysis circuit 17 stores the sampling volume 3 (FIG. 6) in the area where the blood flow exists in the above range.
Is transmitted to the Doppler unit 18. Here, when an operation command of the FFT Doppler mode is input to the main control CPU 22 through an input device (not shown), the blood flow data at the position of the sampling volume 3 is converted to the FF.
After being subjected to frequency analysis in the T Doppler analysis circuit 17, it is sent to the Doppler section 18. This data is sent to the display device 23 via the video section 21 and displayed. The display at this time is C
Simultaneous display of the FM mode and the FFT Doppler mode is also possible.

The data selected by the CFM stream filter 32 may be data individually determined for a blood flow velocity, a velocity dispersion value, and a power value, or a combination of two of the above three data. Alternatively, a combination of three data may be used.

FIG. 3 shows an example of the combination. In the figure, (a) shows the speed of change on the horizontal axis and the power value on the vertical axis, and expresses the boundary line 41 by a linear expression so as to extract only the data in the hatched portion below the boundary line 41. This is the detection condition. This is to detect a portion with a high speed and remove data with a large power value in a region with a low speed to remove a reflected wave from an organ such as a heart wall or a blood vessel wall.

(B) is a graph in which the horizontal axis represents the speed of change and the vertical axis represents the power value, as in FIG. This is for detecting data in an area having a large power value. That is, in the high-speed range, even if the power value is relatively small, detection is performed, but in the low-speed range, only data in a region where the power value is large is to be detected. This is effective when there is a blood flow on the entire screen and it is desired to detect a portion having a large power value at high speed from the blood flow.

In FIG. 3C, the vertical axis represents the velocity dispersion value, and the horizontal axis represents the speed of change, and the boundary 41 is represented by a quadratic equation as a detection condition. In this figure, an area having a relatively small speed variance is detected in a low speed range, and data in an area having a large speed variance is detected as the speed increases.
This is effective for detecting a turbulent flow, and in a turbulent portion of the flow, since the absolute value of the speed variance value is generally large at high speeds, the threshold value of the speed variance value in the high speed portion also increases. I have. In addition, it is also possible to sort by other combinations as necessary.

The operation procedure in the above-described Doppler CFM ultrasonic diagnostic apparatus will be described with reference to the flowchart of FIG. In the figure, the same reference numerals as those used in FIG. 6 are used.

Step 1 A blood flow distribution is searched for in the CFM mode. At this time, the CFM sound ray memory 31 operates as shown in the flowchart of FIG.
The image on the screen of the display device 23 is as shown in column A (a).

Step 2 The FFT Doppler mode is operated. An image as shown in column A (b) appears on the display screen. The sampling volume 3 is displayed on the required blood flow display unit 5 without being moved by the input device, and data on the position of the sampling volume 3 is input to the FFT Doppler analysis circuit 17.
On the screen, in addition to the image shown in (b), the Doppler image shown in (c) is simultaneously displayed.

FIG. 5 shows the CFM in step 1 of FIG.
It is a flowchart which shows operation | movement at the time of searching for the blood flow in mode. Step 1 The CFM sound ray memory 31 receives the input CFM analysis circuit 19
Are cumulatively added for several frames. This is to prevent the position of the sample volume obtained by the search from moving around with the heartbeat, for example, when searching for a site where the blood flow distribution changes rapidly, such as the heart. It is.

Step 2 As shown in the column A, an ECG signal is input to reset the data in the CFM sound ray memory 31 with a signal synchronized with the heartbeat, for example, an R wave. Alternatively, it may be reset by a signal having a specific cycle, for example, every one second. This reset is CFM
This is to avoid overflow of the sound ray memory 31.

Step 3 When operating the FFT Doppler mode from the CFM mode, the CFM sound ray memory 31 is operated according to a certain algorithm.
Find the data stored in. This algorithm is not specified. With this algorithm, for example, blood flow velocity
The data is searched based on a linear function of the speed and the power value, such as m / sec or more or the power value xx or more, or a boundary line 41 shown in FIG. When the data is obtained, the address of the CFM sound ray memory 31 where the data is stored is input to the main control CPU 22. The following continues the operation as described above.

As described above, according to the present embodiment, the sampling volume is automatically selected even if the operator does not move the sampling volume to a place having a blood flow, and the moving operation can be omitted.

The present invention is not limited to the above embodiment. In the embodiment, the CFM unit 20 is configured by hardware, but may be implemented by software.

[0045]

As described above in detail, according to the present invention, after operating the FFT Doppler mode from the CFM mode, the operation of moving the sampling volume can be omitted, and the practical effect is reduced. large.

[Brief description of the drawings]

FIG. 1 is a configuration block diagram of a CFM unit in a DSC according to one embodiment of the present invention.

FIG. 2 is a schematic block diagram of a Doppler CFM ultrasonic diagnostic apparatus including a circuit according to an embodiment of the present invention.

FIG. 3 is a diagram illustrating an example of CFM data selection.

FIG. 4 is a flowchart showing an operation procedure of the apparatus of the embodiment and a diagram showing a display screen at that time.

FIG. 5 is a flowchart showing a circuit operation during operation according to the operation procedure of FIG. 4;

FIG. 6 is a flowchart showing an operation procedure by a conventional device and a screen display at that time.

[Explanation of symbols]

 17 FFT Doppler analysis circuit 19 CFM analysis circuit 22 Main control CPU 31 CFM sound ray memory 32 CFM stream filter 33 Read address generator

Claims (1)

(57) [Claims] A CFM data analyzing means for analyzing a received signal to obtain blood flow distribution data including a blood flow velocity, a velocity variance value or a power value; and a Doppler shift by a blood flow of a predetermined sample volume. FFT Doppler analysis means (17) for frequency analysis; and data area search means (31) for obtaining a specific area based on one or a combination of one or more of a blood flow velocity, a velocity dispersion value, and a power value of the blood flow distribution data. , 32, 33), and the specific area obtained by the data area search means (31, 32, 33) is set as a sample volume to be subjected to the FFT Doppler analysis means (17). Doppler CFM ultrasonic diagnostic equipment.