JPH07323029A - Ultrasonic diagnostic apparatus - Google Patents

Abstract

PURPOSE:To accurately display the ultrasonic image within a region of concern with uniform resolving power and to reduce the lowering of a frame rate by selecting delay data on the basis of an indicated region and the number of focus points and setting the transmission caliber control data of a probe and controlling a transmission circuit on the basis of both data. CONSTITUTION:An F-number capable of realizing uniform resolving power and the max. focus is calculated on the basis of the number of focus stages and the size of a region of concern and converted to caliber element number data on the basis of the element pitch data of a fine vibrator 2. Next, the delay data at the position of a focus point performing transmission is read from a ROM 7 to be inputted to a transmission delay control circuit 6 along with the calculated caliber element number data. The transmission delay control circuit 6 outputs a trigger signal to a transmission pulser 4 on the basis of the delay data and caliber element number data from a CPU 8. The transmission pulser 4 outputs an ultrasonic pulse on the basis of the trigger signal to perform the transmission driving of the fine vibrator 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic diagnostic apparatus, and more particularly to an ultrasonic diagnostic apparatus for applying a driving signal to a plurality of micro-vibrators and displaying an ultrasonic image based on a reflection echo signal from the inside of a living body. .

[0002]

2. Description of the Related Art Ultrasonic diagnostic apparatuses used in the medical field generally display real-time tomographic data on a monitor in real time. This type of ultrasonic diagnostic apparatus includes a probe that transmits and receives ultrasonic waves, a wave transmission circuit that gives a drive pulse to the probe, and an ultrasonic echo signal from the living body received by the probe that receives and processes tomographic data. A circuit, a DSC (digital scan converter) for outputting the obtained tomographic data in synchronization with the TV signal, and a monitor are provided.

In such an ultrasonic diagnostic apparatus, a directivity can be imparted to an ultrasonic beam by giving different delay amounts to a plurality of micro-vibrators constituting a probe during transmission and reception. This is called an electronic scanning method, and a so-called electronic focusing method that narrows a beam at an arbitrary position becomes possible. In the so-called combination focus function of the electronic focusing method, a plurality of focus points at the time of transmitting waves are set, the delay amount given to each micro-vibrator is changed according to each focus point, and an ultrasonic signal is transmitted. One sound ray data is obtained by receiving the reflected echo signal corresponding to each focus point at the time of wave transmission through the micro-vibrator. Two-dimensional tomographic data of the living body can be displayed based on the ultrasonic data obtained by scanning the sound ray data.

In a general ultrasonic diagnostic apparatus, it is known that the lateral resolution at the focal point is inversely proportional to the diameter of the probe, which is determined by the number of diameter elements of the micro-vibrator and the element pitch data. Therefore, when the focus point is a short distance, in order to improve the lateral resolution, it is necessary to regulate the number of aperture elements of the micro-vibrator to reduce the aperture of the probe.

This also applies to the case where the combination focus function described above is used, and the minute diameter when transmitting to a focus point at a short distance causes the aperture diameter of a vibrator to be very small when transmitting to a focus point at a long distance. By making the diameter smaller than the diameter of the vibrator, it is possible to obtain an ultrasonic image with uniform resolution.

[0006]

When the combination focus function at the time of transmission as described above is used, it is necessary to transmit ultrasonic signals to a plurality of focus points in order to obtain one sound ray data. Therefore, in order to avoid mixing of noise during reception, it is necessary to transmit each ultrasonic signal after receiving the ultrasonic signal transmitted immediately before. Therefore, if a large number of focus points are set, a clearer image can be obtained, but the frame rate to the display device is reduced,
There is a problem that the real-time property of diagnosis is impaired.

Therefore, of the obtained ultrasonic images, a region of interest (Focus-ROI) of particular interest is set, only the focus points located within this region of interest are validated, and only the image within this region of interest is validated. It is conceivable to make the image clear and in focus. In this case, the ultrasonic signal is transmitted only to the focus points that are enabled by the setting, and the frame rate can be increased.

However, in the conventional ultrasonic diagnostic apparatus, the focus point used for the combination focus at the time of wave transmission is set in advance, and the delay amount given to each minute vibration is determined accordingly. Therefore,
In order to set the region of interest, it is necessary to perform a key operation for each focus point to set whether the focus point is valid or invalid. In addition, when it is desired to change the region of interest, it is necessary to set valid / invalid of each focus point again. Furthermore, when the size of the region of interest and the number of focus steps are changed, it is necessary to change the aperture of the micro-vibrator according to the size of the region of interest and the number of focus steps in order to make the resolution uniform at each focus point. The aperture control data is set based on a preset number of focus steps, and it is the current situation that an ultrasonic image with a uniform resolution cannot be obtained in the region of interest.

An object of the present invention is to accurately display an ultrasonic image in the region of interest with uniform resolution by setting the region of interest and the number of focus points, and reduce the decrease in frame rate.

[0010]

An ultrasonic diagnostic apparatus according to the present invention comprises a probe, a wave transmission circuit, a wave reception circuit, a display means, a storage means, a region of interest setting means, and a focus step number setting means. And transmission control means. The probe has a plurality of transmitting and receiving micro-oscillators. The wave transmission circuit gives a drive signal to the micro-vibrator to transmit an ultrasonic signal in the living body. The wave receiving circuit receives the reflected echo signal from the living body via the micro-vibrator. The display means displays an ultrasonic image based on the reflected echo signal. The storage means stores the delay data for delaying the drive signal given to each micro-vibrator according to the focus point at the time of transmission. The region of interest setting means specifies a region of particular interest in the obtained ultrasonic image. The focus step number setting means specifies the number of focus points at the time of wave transmission within the area specified by the region of interest setting means.
The transmission control means selects the delay data stored in the storage means based on the area designated by the region of interest setting means and the focus point designated by the focus step number setting means, and controls the transmission aperture of the probe. The aperture control data is set, and the wave transmission circuit is controlled based on the data.

[0011]

In the ultrasonic diagnostic apparatus according to the present invention, a region of interest is designated by the region of interest setting means, and the number of focus points at the time of transmission is designated by the focus step number setting means. The delay data stored in the storage means is selected based on the designated area and the number of focus points, and the aperture control data for controlling the transmission aperture of the probe is set. The transmission circuit is controlled based on the delay data and the aperture control data to transmit the ultrasonic signal into the living body. The reflected echo signal corresponding to each focus point is received by the wave receiving circuit and displayed on the display means as an ultrasonic image.

[0012]

1 is a block diagram showing the configuration of an ultrasonic diagnostic apparatus according to an embodiment of the present invention. In the figure, a probe 1 is composed of a plurality of minute oscillators 2 and is connected to a beam scanning circuit 3. The beam scanning circuit 3 uses electronic scanning,
This is for selecting a micro-vibrator for performing a variable aperture or the like. The beam scanning circuit 3 includes a transmission pulser 4
And the wave receiving circuit 5 are connected. A transmission delay control circuit 6 is connected to the transmission pulser 4. The transmission delay control circuit 6 is connected to a ROM 7 that stores delay data corresponding to the position of each focus point and a central processing circuit (CPU) 8 that controls the entire apparatus.

The receiving circuit 5 includes a reception preamplifier for amplifying the reflected echo signal, a reception delay circuit for performing an electronic focusing method at the time of reception, a logarithmic compression circuit for obtaining tomographic information, and a reception waveform including a low-pass filter. It includes a shaping circuit section, a buffer for temporarily storing tomographic image data, an interpolation calculation circuit section for performing interpolation calculation based on the obtained tomographic information, a digital scan converter having a frame memory in which tomographic image data is written, and the like. There is. A display device 9 such as a CRT monitor is connected to the wave receiving circuit 5. CP
The keyboard 1 on which the operator inputs keys on U8
0 is connected. The receiving circuit 5 and the display device 9 have C
PU8 is connected.

The tomographic image data obtained from the wave receiving circuit 5 is displayed on the display screen of the display device 9 as an ultrasonic image 11 shown in FIG.
In this case, consider a case in which the region of interest (focus ROI) 12 is set on the ultrasonic image 11 and the number of focus steps at the time of wave transmission is set to 3. The operator sets and inputs the number of focus steps at the time of wave transmission by key input of the keyboard 10 (in this case, the number of focus steps is 3). Next, key input is performed from the keyboard 10 so that the region of interest 12 is set on the display screen of the display device 9.
Based on the input number of focus steps and the size of the region of interest 12, the focus points 13, 14 and 15 for transmitting waves are selected, and the ultrasonic image region A for receiving is selected based on the focus points at the time of transmitting each wave. B and C are set and displayed on the display device 9.

The operation at this time will be described with reference to the flowchart of FIG. In step S1, it is judged whether or not the setting input of the number of focus steps at the time of wave transmission is made. Here, it waits for the device input from the keyboard 10 by the operator, and stores it in the RAM in the CPU 8 as a variable indicating the number of focus stages. In the example shown in FIG. 2, the number of focus stages is set to 3.

In step S2, it is determined whether or not the size and position of the region of interest 12 have been set and input. Again, wait for the operator to enter the keyboard 10
The region of interest 12 is stored in the RAM in U8 as a variable. In step S3, the region of interest 12 input in step S2 is displayed on the display screen of the display device 9. At the same time, the depth position of each focus point (the first focus point 13, the second focus point 14, the third focus point 1 in FIG.
5) and the ultrasonic image area (areas A, B, and C in FIG. 2) obtained from each focus point is displayed.

In step S4, it is determined whether the position of the region of interest 12 displayed on the display device 9 is the one desired by the operator. Here, the keyboard 1 by the operator
Waiting for "OK" input from 0, the region of interest setting mode is exited. In step S4, when a key input of "NO" by the operator is received, the process proceeds to step S1 and the setting input is redone.

When transmitting-wave focusing is performed based on the number of focus steps and the region of interest 12 set in FIGS. 2 and 3, ultrasonic image data is displayed according to the flowchart shown in FIG. The ROM 7 stores delay data to be given to the micro-vibrator in advance according to the depth position of the focus point. Based on the number of focus steps set in the region of interest setting mode and the size of the region of interest 12, the designated number of focus steps is selected from the depth positions of the focus points stored in the ROM 7 (step S11). ). In step S12, an F number that can achieve uniform resolution and optimum focus at the focus point intervals selected in step S11 is calculated, and this is converted into aperture element number data based on the element pitch data of the micro-vibrator 2. . The element pitch data is the interval between the micro-vibrators 2 adjacent to each other of the probe 1, and is stored in advance in the ROM in the CPU 8. Based on this element pitch data, the number of micro-vibrators 2 to be driven (the number of aperture elements) is determined so that the transmission aperture diameter of the probe 1 becomes optimum when transmitting waves to the selected focus point.

In step S13, the delay data at the position of the focus point for transmitting the wave is read from the ROM 7 and input to the wave transmission delay control circuit 6 together with the calculated aperture element number data. The transmission delay control circuit 6 outputs a trigger signal to the transmission pulser 4 based on the delay data and the diameter element number data from the CPU 8. Transmission pulser 4
Outputs ultrasonic pulses based on the trigger signal of the transmission delay control circuit 6 to drive the micro-vibrator 2 to transmit waves.

In step S14, the wave receiving circuit 5 receives the reflected echo signal via the micro-vibrator 2, and in step S1
3 is stored in the buffer memory as ultrasonic image data based on the focus point transmitted in 3. In step S15, it is determined whether or not the transmission / reception of the ultrasonic signal has ended for each focus point on one sound ray. If the transmission / reception of the ultrasonic signal has not been completed for each focus point on one sound ray, the process proceeds to step S16. Step S
In 16, the flag of the focus point for transmitting the wave is moved to the next focus point, and the process proceeds to step S13.

When it is determined in step S15 that the transmission / reception of the ultrasonic signal at each focus point on one sound ray data is completed, the process proceeds to step S17.
In step S17, the ultrasonic image data based on each focus point is written as one sound ray data in the frame memory or the like of the digital scan converter.

In step S18, it is determined whether or not the scanning of the designated area is completed. If the scanning of the area is not completed, the process proceeds to step S19. In step S19, the direction of transmitting waves is designated as the next sound ray direction,
Control goes to step S13. In step S18,
If it is determined that the scanning of the specified area has finished,
Control goes to step S20. In step S20, interpolation calculation and the like are performed on the basis of each sound ray data, and the ultrasonic image data is displayed on the display device 9.

[Other Embodiments] (a) Based on the number of focus steps and the size of the region of interest, F number or aperture element number data at each focus point is stored and set in the ROM 7 as an aperture control table. It is also possible to sequentially read this out based on the number of focus steps and the size of the region of interest to control the aperture during transmission. (B) To specify the region of interest 12 in FIG. 2, it is possible to use a joystick, a mouse, or the like.

[0024]

In the ultrasonic diagnostic apparatus according to the present invention, a region of particular interest in the ultrasonic image obtained by the region-of-interest setting means is designated, and within the region designated by the region-of-interest setting means by the focus step number setting means. If the number of focus points during transmission is specified, the transmission control means selects delay data based on the specified area and the number of focus points, and sets the aperture control data to control the transmission circuit. It is possible to accurately display the ultrasonic image in the inside with a uniform resolution, and it is possible to reduce the decrease in the frame rate.

[Brief description of drawings]

FIG. 1 is a control block diagram of an embodiment in which the present invention is adopted.

FIG. 2 is an explanatory diagram showing a display example of an ultrasonic image.

FIG. 3 is a control flowchart of an embodiment of the present invention.

FIG. 4 is a control flowchart of an embodiment of the present invention.

[Explanation of symbols]

 1 probe 2 micro-vibrator 3 beam scanning circuit 4 transmission pulser 5 reception circuit 6 transmission delay control circuit 7 ROM 8 CPU 9 display device 10 keyboard

Claims (1)

[Claims] 1. A probe having a plurality of transmission / reception microvibrators, a wave transmission circuit for giving a drive signal to the microvibrators and transmitting an ultrasonic wave signal in a living body, and a reflection echo signal from the living body. A receiving circuit that receives via the micro-vibrator, a display unit that displays an ultrasonic image based on the reflected echo signal, and a drive signal to be given to each micro-vibrator according to a focus point at the time of transmission. A storage unit for storing delay data to be delayed, a region of interest setting unit for designating a region of particular interest in an ultrasonic image to be obtained, and a number of focus points at the time of transmission within the region designated by the region of interest setting unit Focus step number setting means, and the area stored in the storage means based on the area designated by the region of interest setting means and the focus point designated by the focus step number setting means. The ultrasonic diagnostic apparatus is provided with: a transmission control unit that selects the delay data, sets the aperture control data that controls the transmission aperture of the probe, and controls the transmission circuit.