JPH06319736A - Ultrasonic doppler diagnostic apparatus - Google Patents

Abstract

PURPOSE:To enhance the visuality of speed data by altering the display range of the speed data of a motion fluid displayed on a monitor corresponding to the set value of sampling frequency. CONSTITUTION:The ultrasonic echo signal from the motion fluid in a living body is sampled on the basis of the sampling frequency set to a required range in a PRF setting part 8 and subsequently analyzed by a Doppler analyzing means 3 to calculate speed data (Doppler spectrum) and this speed data is displayed on a monitor 6 by an image display control means 4. When the setting of sampling frequency is altered in the PRF setting part 8, a CPU 9 being a display range altering means, a frame memory 26 and a writing/reading control part 27 change the display range on the monitor 6 displaying the speed data corresponding to the altered value of sampling frequency. At that time, since the display width of the speed data is not changed, the always stable speed data can be confirmed and the visuality of the speed data can be enhanced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic Doppler diagnostic apparatus for obtaining velocity data such as blood flow by utilizing the Doppler effect of ultrasonic waves, and more particularly to an ultrasonic Doppler diagnostic apparatus on a monitor corresponding to a set value of sampling frequency. The present invention relates to an ultrasonic Doppler diagnostic device that changes a display range.

[0002]

2. Description of the Related Art An ultrasonic Doppler diagnostic apparatus uses a real-time tomographic image of a living body based on an ultrasonic echo signal and velocity information of a moving fluid in the living body obtained by Doppler analysis of the ultrasonic echo signal. In addition, the diagnosis is performed by displaying it on the monitor in an accurate image mode, which dramatically improves the diagnosis efficiency.

Display examples on a monitor of such an ultrasonic Doppler diagnostic apparatus are shown in FIGS. 10 (a) and 10 (b). A tomographic image B of a predetermined scan plane and a Doppler spectrum V1 representing blood flow velocity information are displayed on the monitor in real time. A spectrum display is used for displaying the speed information, in which the horizontal axis represents time, the vertical axis represents the Doppler shift frequency (speed), and the luminance is the power of each Doppler shift frequency.

On the monitor, the Doppler spectrum is always displayed within a fixed size range. A scale is set in the vertical axis direction as a scale of the Doppler spectrum displayed within this range. This scale refers to the sampling frequency (here, both pulse Doppler and continuous wave Doppler sampling frequencies. PRF as a symbol)
When (Use pulse repetition frequency) is PRF = f1, the full scale is normally set to fall within the frequency range of -1 / 2f1 to 1 / 2f1. The PRF value is always displayed on the monitor, and the flow velocity of the kinetic fluid is obtained based on this value, so the PRF is also called a flow velocity range.

In such an ultrasonic diagnostic apparatus, when the operator or the like wants to change the scale for the sake of diagnosis, he or she changes the setting of PRF to do so.

[0006]

When the setting of the PRF is changed for the convenience of diagnosis, the display width of the Doppler spectrum in the vertical direction (apparent amplitude on the monitor) also changes accordingly. For example, PRF is changed from PRF = f1 (display state in FIG. 10A) to PRF = f2 as shown in FIG.
(F2 = 2f1; that is, the PRF is doubled), the display width of the Doppler spectrum V1 in the vertical axis direction is halved. As described above, according to the conventional display method, when the PRF setting is changed, the change amount of the PRF and the change amount of the display width in the vertical direction of the Doppler spectrum do not sensuously match, so that the operator can visually check the monitor. , It was difficult to quickly check whether the velocity information of the moving fluid shows an appropriate value.

The present invention has been made in view of the above-mentioned circumstances, and it is possible to improve the visibility of speed information by changing the display range of speed information in accordance with the set value of PRF. An object is to provide a sonic Doppler diagnostic device.

[0008]

In order to achieve the above-mentioned object, the ultrasonic Doppler diagnostic apparatus according to claim 1 uses an ultrasonic echo signal from a kinetic fluid in a living body at a sampling frequency set within a required range. Doppler analysis means for sampling and obtaining the Doppler shift frequency of the fluid, frequency-analyzing the Doppler shift frequency to obtain velocity information of the fluid, and image display control for displaying the velocity information of the fluid on a monitor And means. Further, a display range changing means for changing the display range on the monitor according to the set value of the sampling frequency is provided.

[0009]

[Operation] The ultrasonic echo signal from the moving fluid in the living body is
After being sampled at a sampling frequency set within a required range, the Doppler analysis unit analyzes it to obtain velocity information (Doppler spectrum), which is displayed on the monitor by the image display control unit. Here, when the setting of the sampling frequency is changed, the display range changing means changes the display range on the monitor showing the speed information corresponding to the changed value of the sampling frequency. At this time, since the display width of the speed information does not change, stable speed information can always be recognized.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

A first embodiment will be described with reference to FIGS. In the present embodiment, a case will be described in which pulse wave is used as the transmitted ultrasonic wave to measure blood flow velocity information in the living body.

A block diagram of an ultrasonic Doppler diagnostic apparatus in the first embodiment is shown in FIG.

The ultrasonic Doppler diagnostic apparatus shown in FIG. 1 is an ultrasonic probe 1 capable of bidirectionally converting a voltage signal and an ultrasonic signal, and an ultrasonic beam is excited in the living body H by exciting the ultrasonic probe 1. The electronic scanning unit 2 for receiving and processing the ultrasonic echo signal received by the ultrasonic probe 1, and the output signal before detection of the electronic scanning unit 2 by Doppler analysis to perform the Doppler frequency. And the Doppler analysis unit 3 as a Doppler analysis unit for frequency analysis of the Doppler frequency to obtain velocity information, the output signal after detection of the electronic scanning unit 2 and the velocity information output from the Doppler analysis unit 3. An image display control unit 4 as an image display control means for converting into a standard TV signal is provided. This image display control unit 4
The output from is converted into an analog signal through the D / A converter 5, and is displayed as an image on the TV monitor 6.

Also, this ultrasonic Doppler diagnostic apparatus is a TV
A graphic data holding unit 7 holding graphic data such as markers and scales displayed on the monitor 6 is provided.

Further, the ultrasonic Doppler diagnostic apparatus includes a PRF setting section 8 for setting a sampling frequency (PRF),
It has an internal memory and is provided with a central processing unit (CPU) 9 for performing the processing of FIG. This CPU9
A memory 10 is connected to the
The procedure of the process executed in U9 and the data necessary for the process are stored in advance. The PRF set by the PRF setting unit 8 is set within the range of PRF = 3 kHz to 12 kHz in the case of the pulse Doppler method according to this embodiment.

The electronic scanning unit 2, as shown in FIG.
A pulse generator 11 that generates a rate pulse having a repetition frequency equal to the PRF set by the PRF setting unit 8 and a high-voltage transmission pulse are generated from the rate pulse output from the pulse generator 11 and applied to the ultrasonic probe 1. In addition, the transmission / reception unit 12 that amplifies the reception signal from the ultrasonic probe 1, the delay line 13 that delays the transmission signal and the reception signal to perform scanning such as sector scanning and focus processing of the transmission signal, and a delay line An adder 14 that adds the received signals delayed by the line 13, a detector 15 that detects the added received signals, and an A / that converts the output signal (analog) from the detector 15 into a digital signal.
A D converter 16 is provided, and the output of the A / D converter 16 (hereinafter referred to as B mode image data) is output to the image display control unit 4.

Further, as shown in FIG. 2, the Doppler analysis unit 3 receives a phasing addition output from the adder 14 and performs a phase detection, which is a detection unit 19 (comprising a mixer 17 and a low-pass filter 18). And a sampling pulse (frequency: P) delayed by a time corresponding to the sampling position of the blood flow in response to the rate pulse from the pulse generator 11.
Based on the range gate unit 20 that outputs RF) and the sampling pulse that is output from the range gate unit 20,
A sample hold unit 21 that samples a Doppler signal from a blood flow sampling position, a Doppler filter 22 that removes frequency components in an unnecessary band of the sampled Doppler signal, and an A / A that converts an analog signal into a digital signal. A D converter 23 and a fast Fourier transformer (FFT) 24 for frequency analysis are provided. Doppler signal is A
After being converted into a digital signal by the / D converter 23,
Frequency analysis is performed by the FFT 24, and the analysis result (hereinafter referred to as Doppler data) is output to the image display control unit 4.

The graphic data holding section 7 has a memory for storing graphic data such as scales and markers, the graphic data is read out in response to a control signal from the CPU 9, and the image display control section 4 serves as the graphic data. Is output to.

On the other hand, the image display controller 4 receives the input B
The mode image data, the Doppler data, and the graphic data are converted into TV scanning type data, and the scanning conversion unit 25 that holds the converted data in the buffer unit and the pixels on the screen of the TV monitor 6 correspond one to one. And a frame memory 26 having a storage area
A write / read control unit 27 that specifies an appropriate address in 6 to write the data output from the scan conversion unit 25 to the storage area of the specified address, and that reads the data from the storage area of the specified address. It has and.

The writing / reading control unit 27 has a C
Upon receiving the control signal from the PU 9, the B-mode image data, the Doppler data, and the graphic data held in the scan conversion unit 25 are written in the frame memory 26. On this occasion,
When writing data to the frame memory 26, the format of writing data to the frame memory 26 is as to which area and range of the B mode image data, Doppler data, and graphic data to be displayed on the TV monitor 6. The write address (in this embodiment, the write start address (start address) and the write end address (end address)) is set appropriately. The write address of the B mode data is predetermined and written in a predetermined area in a predetermined range, but the write addresses of the Doppler data and the graphic data change depending on the set value of PRF.

Further, the memory 10 has a storage table as data necessary for the processing of the CPU 9. This storage table stores the data of the write address corresponding to the value of PRF. Here, the correspondence relationship between the PRF and the write address will be described with reference to FIGS.

FIG. 3 shows the relationship between the PRF and the display range of the Doppler data displayed on the monitor in the vertical direction (hereinafter, simply referred to as the display range of the Doppler data). As shown in FIG. 3, the display range of the Doppler data increases in proportion to the increase in PRF. That is, the write address is determined so that the PRF and the display range of the Doppler data displayed on the monitor have a proportional relationship. In the case of this embodiment, since the PRF range is 3 kHz to 12 kHz, the PR
The display range of Doppler data is maximum when F = 12kHz (maximum value), and the display range of Doppler data is minimum when PRF = 3kHz (minimum value).

An example of the relationship between the storage area and the write address when writing the Doppler data in the frame memory 26 is shown in FIGS. F ₁ and F ₂ in the figure are schematic diagrams showing storage areas assigned to the Doppler data of the frame memory. m ₁ , m ₂ , and m ₃ are analysis data (Doppler data) corresponding to the Doppler spectrum on the monitor of a certain time phase analyzed by the FFT 24. The circles in the figure represent the Doppler data stored for each pixel in the Doppler area. Also, A _S1 and A _S2 represent start addresses, and A _E1 and A _E2 represent end addresses.

In FIG. 4A, when PRF = 12 kHz, the Doppler data is A _E1 from the pixel designated by A _S1.
The pixels specified by are sequentially stored. In this case, the range of the Doppler data displayed on the monitor is the maximum value D1. Further, when the setting is changed to PRF = 6KHZ, the Doppler data is sequentially stored from the pixel designated by A _S2 to the pixel designated by A _E2 as shown in FIG. 4B, and is displayed on the monitor. Range is D2 (D2 = D
1/2).

On the other hand, when reading the data stored in the storage area, the write / read control unit 27 specifies an address and the data stored in the storage area specified by this address (read address) is read. Be done. This data is displayed as an image on the TV monitor 6 via the D / A converter 5.

Now, the processing of the CPU 9 described above will be described with reference to FIG.

First, in step 100 of FIG. 5, the CPU 9
Reads the PRF set by the PRF setting unit 8, temporarily holds the contents in the internal memory, and shifts to the processing of step 101. CP in step 101
U9 looks up the storage table and reads the write address corresponding to the PRF stored in the internal memory from the storage table. Next, in step 102, the display address of the graphic data corresponding to the write address is calculated. Then, the write address is sent to the write / read controller 27 in step 103, and the display address of the graphic data is sent to the write / read controller 27 in step 104. And
In step 105, it is determined whether or not the PRF control is ended. If the result of this determination is YES, the process is terminated, while if the result is NO, the process proceeds to step 106 to read the PRF and store it in the internal memory. Next, at step 107, the CPU 9 causes the step 100 to proceed.
The PRF value stored in step 106 and the PRF value stored in step 106
It is compared with RF to determine whether the setting has been changed. In the case of YES in this determination, it is determined that the setting of the PRF has been changed, the process returns to the above-described step 101, the write address based on the newly set PRF is read, and in the case of NO, the above-described step 105 is performed. Returning to the processing, it is judged whether or not the PRF control is ended. Hereinafter, the above-mentioned processing is repeated.

The processing in steps 100 to 104, the PRF setting section 8, the frame memory 26, and the writing / reading control section 27 constitute the display range changing means.

Next, the overall operation will be described.

If the operator or the like has set the PRF to 6 kHz in advance in the PRF setting section 8, the ultrasonic probe 1 radiates ultrasonic waves (pulse waves) having a repetition frequency of 6 kHz to the diagnostic region of the living body. Then, the ultrasonic waves reflected by the diagnostic region are received and processed by the electronic scanning unit 2.
It becomes mode image data and is input to the scan conversion unit 25. In addition, a part of the signal received by the electronic scanning unit 2 is obtained by the Doppler analysis unit 3 as Doppler data that is the frequency analysis result of the Doppler signal from the target blood flow, and is input to the scan conversion unit 25.

Further, graphic data such as a predetermined scale and marker held in the graphic data holding unit 7 is also input to the scan conversion unit 25.

On the other hand, the CPU 9 receives the P from the PRF setting section 8.
RF (6kHz) information is sent. The CPU 9 is shown in FIG.
This is because the process of
The PRF is read into U9, and the processing from step 101 to step 105 in FIG. 5 is executed. That is, the write address corresponding to PRF (6 kHz) is read by referring to the storage table (see step 101). The display address of the graphic data corresponding to the write address is calculated (see step 102). Then, the output command signal of the write address and the graphic data display address is output to the writing / reading control unit (see step 103), and the graphic data output command signal is further output to the graphic data holding unit (see step 104). . Here, if there is no intention to change the PRF setting as it is, the process ends (see step 105).

From the relationship shown in FIGS. 4 (a) and 4 (b), the writing / reading control section 27 has a half range (FIG. 4 () in comparison with the display range of the Doppler data in the case of PRF = 12 kHz. A write address such as D2) of b) is sent, and a display address of graphic data corresponding to the write address is sent.

Then, the write / read controller 27
The scan converter 25 is provided with a write address of the Doppler data,
A data write command is issued based on the display address of the graphic data and the write address of the B-mode data, whereby all the data is written on the frame memory 26.

Data is read from the frame memory 26 at a predetermined timing, and this data is sent to the TV monitor 6 via the D / A converter 5 and displayed as an image. The result is shown in FIG. FIG. 6A shows a B-mode tomographic image B1 and a Doppler spectrum D that is Doppler data.
P1 is displayed.

On the other hand, for the convenience of diagnosis, the PRF is set to PR.
Suppose you changed to F = 12kHz. At this time, step 10
The determination of 5 is NO, and the value of PRF is read again (see step 106). Since the set value of PRF has been changed from 6kHz to 12kHz, YE is performed in step 107.
Judge S. As a result, the processing of steps 101 to 105 described above is performed again.

Therefore, the Doppler data is stored on the frame memory 26 so that the display range (D1) shown in FIG. Further, since the writing / reading control unit 27 repeats the above-described processing, the B-mode tomographic image B1 is displayed on the TV monitor 6 as shown in FIG. 6B.
Doppler spectrum DP2 which is Doppler data is displayed.

As can be seen by comparing FIGS. 6 (a) and 6 (b), even if the PRF setting is doubled, the Doppler spectrum DP2 is changed only by double the display range of the Doppler data. The display width of does not change. Therefore, the operator can quickly check whether the Doppler data value shows an appropriate value while observing the TV monitor 6 regardless of the change in the PRF setting.

In this embodiment, a continuous wave may be used as the transmitted ultrasonic wave. The PRF in this case is, for example,
Since it is possible to set a wide range of frequencies from 4kHz to 50kHz, the relationship between the PRF and the Doppler data display range
The write address is set so as to expand stepwise as shown in FIG. The display range of the Doppler data on the monitor is stepwise expanded to H1, H2, H3, ... Corresponding to the set value of PRF as shown in FIG. 7B, but the display width of the Doppler data is It does not change. Therefore, even when a continuous wave is used as the transmitted ultrasonic wave, the operator can quickly check whether the value of the Doppler data shows an appropriate value while observing the TV monitor 6 regardless of the setting change of the PRF. . Other configurations and operations are the same as those described in the present embodiment, and therefore description thereof will be omitted.

As a second embodiment, the change of the display range corresponding to the set value of PRF based on the processing of the CPU as described above is performed in the output width control unit 28 provided in the preceding stage of the image display control unit 4. It can also be configured as follows. An ultrasonic Doppler diagnostic apparatus having this configuration is shown in FIG. An example of the output width control method by the output width control unit 28 is shown in FIG.
It will be described based on.

The output width control unit 28 temporarily holds the Doppler data D4 (the data string of one analysis data is shown in the figure) input from the Doppler analysis unit 3 to the output width control unit 28 in a buffer or the like. . Then, the output width of the Doppler data D4 held in the buffer is controlled so as to have a desired output width by masking the zero data in response to the control signal indicating the display range based on the set value of PRF from the CPU 9. As a result, the Doppler data of the output width G1 is the output width G2.
It becomes Doppler data of <G1) and is read by the image display control unit 4.

As a result, the display range of the Doppler data can be changed corresponding to the set value of PRF as in the first embodiment. As an output width control method of the output width control unit 28, the output width can be controlled by averaging a plurality of data in one Doppler data, and the same effect can be obtained.

[0043]

As described above, according to the ultrasonic Doppler diagnostic apparatus of the present invention, an ultrasonic echo signal from a moving fluid in a living body is sampled at a sampling frequency set within a required range and obtained. If the setting value of the sampling frequency is changed when the speed information (Doppler spectrum) obtained by frequency analysis of the obtained Doppler frequency is displayed on the monitor, the display range changes according to this sampling frequency. By doing so, the display width of the speed information does not change, and stable speed information can always be recognized and the visibility is improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of a first embodiment of an ultrasonic Doppler diagnostic apparatus according to the present invention.

FIG. 2 is a block diagram showing a configuration of an electronic scanning unit and a Doppler conversion unit in the first embodiment.

FIG. 3 is a graph showing the relationship between PRF and display area in the first embodiment.

FIG. 4 is an explanatory diagram showing a relationship between a storage area on a frame memory and its address in the first embodiment.

FIG. 5 is a schematic flowchart showing a processing example of a central processing unit (CPU) in the first embodiment.

6A and 6B are diagrams showing display examples on the monitor of the first embodiment.

7A and 7B are PRFs in the first embodiment.
Explanatory drawing which shows the relationship between a display area.

FIG. 8 is a block diagram showing the configuration of a second embodiment of the ultrasonic Doppler diagnostic apparatus according to the present invention.

FIG. 9 is a diagram illustrating a Doppler data output width control method according to the second embodiment.

FIG. 10 is a diagram showing a display example on a conventional monitor.

[Explanation of Codes] 1 Ultrasonic probe 2 Electronic scanning unit 3 Doppler analysis unit 4 Image display conversion unit 5 D / A converter 6 TV monitor 7 Graphic data holding unit 8 PRF setting unit 9 Central processing unit (CPU) 10 Memory 25 Scan conversion unit 26 Frame memory 27 Writing / reading control unit

Claims (1)

[Claims] 1. An ultrasonic echo signal from a moving fluid in a living body is sampled at a sampling frequency set within a required range to obtain a Doppler shift frequency of the fluid, and the Doppler shift frequency is subjected to frequency analysis. In the ultrasonic Doppler diagnostic apparatus including a Doppler analysis unit for obtaining velocity information of the fluid and an image display control unit for displaying the velocity information of the fluid on a monitor, the display range on the monitor is set to the sampling frequency of the sampling frequency. An ultrasonic Doppler diagnostic apparatus comprising display range changing means for changing the set value according to the set value.