JPH06189961A - Ultrasonic diagnostic device - Google Patents

Abstract

PURPOSE:To enhance a resolution with small data capacity by applying the constitution where a plurality of wave transmission focus points are established, an ultrasonic wave is transmitted on different timing, depending upon a focus position, and then a diagnostic image is displayed using resulting sound ray data. CONSTITUTION:Receiving circuits 3 and 4 are connected through the 'n' number (for example, eight) of signal lines to a multiplexer 2 connected to a probe 1 for electronic scanning via the 'N' number of signal lines. A wave transmission circuit 3 is controlled with a wave transmission focus control section 5, so that drive pulses delayed for focusing an ultrasonic beam at each focus point can be applied to the probe 1. The circuit 3 has the 'n' number of drive pulse generation circuits, and the pulse generation circuit selected depending upon bore data from a general control circuit 9 is actuated, thereby controlling the bore to be variable. The circuit 9 establishes a focus position on the basis of a display zone and the number of focus points, and generates focus address data and bore data.

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 in particular, it sets a plurality of transmission focus points and transmits ultrasonic pulses at different transmission timings depending on the focus position to obtain the obtained sound. The present invention relates to a multi-stage focus ultrasonic diagnostic apparatus that displays a diagnostic image based on line data.

[0002]

2. Description of the Related Art As a beam scanning method in an ultrasonic diagnostic apparatus, an electronic scanning method is generally used. In this electronic scanning method, a plurality of micro-vibrators forming a probe are provided with different delay amounts, so that the ultrasonic beam has directivity.

Such an electronic scanning method enables a so-called electronic focusing method in which a beam is focused at an arbitrary position. In this electronic focusing method, for example, an ultrasonic wave reflected from a focus point in a living body is received by each micro-vibrator, and an appropriate delay time is given to each signal obtained by each micro-vibrator. , The phases of the signals from the focus points are matched and the signals are added. The focus setting at the time of transmission is also the same, and the transmission ultrasonic beam is narrowed down at a predetermined focus point by giving the same delay time to the focus point as that of reception to each micro-vibrator.

By using the electronic focusing method as described above, a multi-step focusing method (transmission dynamic focusing method) for obtaining an image with good resolution over the entire region from a shallow portion to a deep portion of a living body is possible. The multi-stage focus method sets a plurality of focus points according to the depth of the living body, transmits and receives ultrasonic waves to each of these focus points, and stores the data obtained at each focus point in the memory in the DSC. Then, one scan line data is created.

In this kind of multi-stage focus type ultrasonic diagnostic apparatus, conventionally, a storage means for storing data for designating a focus point is provided. The storage means stores data in which the aperture and the delay time are paired corresponding to the focus point. When the position of the focus point is designated by a key operation or the like, a set of data including the aperture of the focus point and the delay time is read out by the storage means, and the read out data is supplied to the wave transmission circuit and the ultrasonic beam is transmitted. Is transmitted.

[0006]

In this type of multi-stage focusing ultrasonic diagnostic apparatus, the size of the image area to be displayed differs depending on the size of the image display area even at the same focus position. It becomes a thing. For example, if the display area of the image is 15 cm deep from the surface of the living body,
In the case of cm to 11 cm, the display area in the depth direction is 15 cm and 8 cm, respectively. Therefore, for example, in the case of three-stage focus, the position of the focus point is
When the display area is wide, it is set to 3, 7, 11 cm, for example, and when the display area is narrow, it is set to 5, 7, 9 cm. In this example, the size of the image area displayed by the transmission with one focus point is 4 cm when the display area is wide, and 2 cm when the display area is narrow. That is, even if the focus points are at the same depth position, the size of the image area displayed at each focus point changes depending on the size of the entire display area. Therefore, when only one set of delay time and aperture correspond to the focus point at the same depth position, the resolution deteriorates due to the change in the size of the image area. In order to prevent this deterioration of resolution, it is possible to adopt a variable aperture. With the variable aperture, the aperture can be changed according to the size of the display area even at the same focus position.

However, in order to realize this variable aperture, it is necessary to have one set of data including the aperture and the delay time for one focus position depending on the size of the display area. The volume of data that specifies the focus point increases. An object of the present invention is to improve resolution with a small data capacity.

[0008]

The ultrasonic diagnostic apparatus according to the present invention is obtained by setting a plurality of transmission focus points and transmitting ultrasonic pulses at different transmission timings depending on the focus position. This is a multi-stage focus system device that displays a diagnostic image based on sound ray data. This apparatus includes area setting means, focus point setting means, focus position setting means, and aperture control means.

The area setting means is for setting the display area of the diagnostic image. Focus point setting means,
This is for setting the number of transmission focus points. The focus position setting means sets the focus positions corresponding to the number of focus points by the display area set by the area setting means and the number of transmission focus points set by the focus point number setting means. The aperture control means controls the aperture according to the focus position set by the focus position setting means.

[0010]

In the ultrasonic diagnostic apparatus according to the present invention, when the display area is set by the area setting means and the focus point number is set by the focus point number setting means, the focus is set by the set display area and the transmission focus point number. The position setting means sets focus positions corresponding to the number of focus points. When the focus position is set, the aperture control unit controls the aperture according to the focus position. Then, ultrasonic pulses are transmitted by the number of focus points with a controlled aperture at the set focus position.

Here, since the aperture is controlled according to the set focus position, the aperture is optimally adjusted for all combinations of focus positions without increasing the volume of data for setting the focus point. Can send sound pulse. Therefore, the resolution of the image can be improved without increasing the data capacity.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an overall schematic configuration of a multi-stage focus type ultrasonic diagnostic apparatus according to an embodiment of the present invention. In the figure, a probe 1 is composed of N (for example, 128) micro-vibrators arranged in parallel at intervals of 0.5 mm, for example, and is connected to a multiplexer 2. The multiplexer 2 is for performing electronic scanning, and the multiplexer 2 and the probe 1 are connected by N signal lines. The wave transmitting circuit 3 and the wave receiving circuit 4 are connected to the multiplexer 2. The multiplexer 2, the wave transmitting circuit 3, and the wave receiving circuit 4 are connected by signal lines of the maximum number n of simultaneous driving elements (for example, 48). The value obtained by multiplying the number n by the transducer interval (for example, 0.5 mm) becomes the maximum aperture (for example, 24 mm) of the probe 1.

The wave transmission circuit 3 uses a drive pulse delayed to converge the ultrasonic beam at each focus point into the probe 1.
To give to. A wave transmission focus control unit 5 is connected to the wave transmission circuit 3. The wave transmission focus control unit 5 gives the wave transmission circuit 3 delay data for wave transmission according to the focus position. The wave receiving circuit 4 includes a phase synthesizing circuit for phasing and adding reflected echoes, and a logarithmic amplification detection circuit for performing logarithmic amplification and detection processing for obtaining tomographic data. The receiving circuit 4 is connected to the receiving focus control section 6. The reception focus control unit 6 gives delay data for reception to the reception circuit 4. The receiving circuit 4 has a DSC 7
Are connected. The DSC 7 has an image memory, and converts the image data input at the transmission timing of the ultrasonic beam into a standard television signal. Further, the DSC 10 stores data corresponding to the number of focus points corresponding to the focus areas, and the data corresponding to the number of focus points are combined in the respective focus areas to obtain one sound ray data. A monitor 8 is connected to the DSC 10.

Further, the multiplexer 2, the wave transmission focus control section 5, the wave transmission circuit 3, the wave transmission focus control section 6 and D.
The whole control circuit 9 is connected to SC7. The overall control circuit 9 is composed of a microcomputer including a CPU, ROM, RAM and the like. A keyboard 10 is connected to the overall control circuit 9. The keyboard 10 is provided with various keys such as a step number key for setting the number of focus points, a size key for setting a display size (magnification), and a cursor key for setting a display position. The overall control circuit 9 controls the entire device,
The display area is obtained from the display size and the display position, the focus position is set by the number of steps and the display area, and the focus address data and the aperture data are generated.

As shown in FIG. 2, the transmitting circuit 3 has n
Drive pulse generation circuit 13₁~ 13 _nAnd drive pulse
Raw circuit 13₁~ 13_nTo generate a drive pulse from
N trigger generating circuits 12 for generating the trigger signals of
₁~ 12_nAnd are provided. Drive pulse generation circuit 1
Three₁~ 13_nDrive pulse from
And provided to the probe 1. Also, the transmission focus system
The control circuit 5 stores delay data such as a ROM.
A section 11 is provided. The delay data storage unit 11 has the same
Focus with a maximum of n elements of delay data as one set
The data for the position is stored. Focus for example
The position can be set up to 20 cm in 1 cm increments from the surface of the living body.
In the case of Noh, 20 sets of data are stored.
Any one of the delays stored in the delay data storage unit 11
The data is the trigger generation circuit 12 respectively.₁~ 12_nTo
Given. Also, the trigger generation circuit 12₁~ 12_nTo
Is supplied with diameter data from the overall control circuit 9. here
Then, according to the diameter data, the trigger generation circuit 12₁~ 1
Two_nIs selected and driven from the selected trigger generation circuit
A trigger signal is given to the pulse generation circuit. By this
The caliber can be variably controlled. Generation of this trigger signal
The timing is the delay data given from the delay data storage unit 11.
Defined by

Next, the operation of the above embodiment will be described with reference to the flow charts shown in FIGS. In the overall control circuit 9, when the program starts, first, in step S1, initialization is performed. Here, for example, the focus is initially set to one step, the display position is initially set to 25 cm from the living body surface, and the display size is initially set to the same size. In step S2, it is determined whether or not the size key has been operated. In step S3, it is determined whether the step number key is operated. In step S4, it is determined whether or not the cursor key has been operated. In step S5, it is determined whether a calculation flag described later is set. In step S6, it is determined whether or not a wave transmission command is issued. Step S6
If the determination is NO, the process proceeds to step S7 and other processes are performed. When other processing ends, step S
Return to 2.

If it is determined in step S2 that the size key has been operated, the process proceeds to step S8. In step S8, the operation flag is set. The calculation flag is a flag that is set when the focus address data and the aperture data are calculated according to the set display area. In step S9, the display size is set according to the size key input.

If it is determined in step S3 that the step number key has been operated, the process proceeds to step S10. In step S10, the operation flag is set. In step S11, the number of stages is set according to the operation content of the stage number key. In setting the number of stages, the operator inputs the number of stages in consideration of the frame rate. In this multi-stage focusing method, the frame rate is reduced to 1 / the number of focus points, so if the number of stages is increased, the frame rate decreases and it becomes impossible to cope with fast-changing movements. Therefore, the operator sets the number of stages according to the movement of the display image.

If it is determined in step S4 that the cursor key has been operated, the process proceeds to step S12. Step S1
At 2, the operation flag is set. In step S13, the display position is set according to the cursor key. When this cursor key is operated, for example, the display screen scrolls up and down. If it is determined in step S5 that the calculation flag is set, the process proceeds to step S14. In step S14, the arithmetic processing shown in FIG. 4 is performed.

First, the display size set in step S21 is read. In step S22, the set display position is read. In step S23, the set number of stages is read. When these data are read, the display area is calculated in step S24. In other words, the display area indicating which depth area of the living body the operator wants to observe is calculated from the data of the display size and the display position. The data indicating the calculated display area is also displayed in the data 8. In step S25, the focus position corresponding to the display area is set by the display area calculated in step S24. In this setting, for example, an intermediate (M) focus position is set at the center of the display area, and a shallow portion (N) and a deep portion (F) are respectively provided at approximately half the distance between the center and the upper and lower ends of the area. Set the focus position.
For example, when the display area is calculated to be in the range of 4 cm to 12 cm below the surface and the number of steps is set to three-step focus, the three focus positions are set to 6, 8 and 10 cm. Also, the display area is 2 cm to 16 cm below the surface.
In the case of three-stage focus, the three focus positions are set to 4, 8 and 12 cm, for example.

In step S26, the aperture is calculated based on the set focus position, and aperture data for selecting the transducer according to the aperture is obtained. At the time of calculating the aperture, the F number indicating the ratio of the depth to the aperture is set in advance according to the display area, and the aperture is obtained from the set F number. For example, when the F number is 4 and the focus points are 6, 8 and 10 cm, the apertures are 1.5, 2 and 2.5 cm, respectively. If the distance between the transducers is 0.5 mm, the diameter data is 30,4.
It becomes 0,50. However, the maximum number of simultaneous elements n is 48, for example.
Since it is an element, the deepest focus position (for example, 1
0 cm), maximum diameter (number of elements n is 48 elements)
Drive with. Further, when the display area is wide and the focus positions are wide, the focus depth becomes shallow unless the focus is gently applied, resulting in discontinuity in resolution. Therefore, when the distance between the focus points is wide, the F number is gradually set to a small value to reduce the aperture.

In step S27, focus address data for reading the data corresponding to the set focus position is calculated by the number of focus points. Step S2
In 8, the calculation flag is reset and the process returns to the main routine. If it is determined in step S6 of FIG. 3 that the transmission command has been issued, the process proceeds to step S15. In step S15,
The focus address data for each focus position is output. For example, when the focus position is 6, 8 or 10 cm, focus address data of 6 cm is first output. In step S16, the aperture data (for example, 30) at 6 cm is also output. In step S17, it is determined whether or not the transmission for the number of stages (for the number of focus points) has been completed. If the wave transmission has not ended, the process returns to step S15 to perform the next wave transmission, and the focus address data of the next focus position (8 cm) is output. When the output of focus address data and aperture data for the number of focus points is completed, the process returns to the main routine.

Here, the delay data storage unit 11 stores only one set of delay data for the maximum simultaneous drive elements (maximum aperture) n for a settable focus position, and the optimum aperture corresponding to the display area is stored. Therefore, the resolution can be improved without increasing the data capacity. [Other Embodiments] (a) Although the focus address data and the aperture data are calculated by software in the above embodiment, they may be calculated by hardware.

(B) The present invention can be similarly applied to sector scanning or convex scanning instead of linear scanning.

[0025]

In the multi-stage focus type ultrasonic diagnostic apparatus according to the present invention, since the aperture is controlled according to the focus position set by the display area and the number of focus points, the resolution can be improved with a small number of data. Can be planned.

[Brief description of drawings]

FIG. 1 is an overall schematic diagram of an ultrasonic diagnostic apparatus of a multi-stage focus type according to an embodiment of the present invention.

FIG. 2 is a block diagram of the wave transmission circuit and the wave transmission focus control circuit.

FIG. 3 is a control flowchart of the overall control circuit.

FIG. 4 is a control flowchart of the overall control circuit.

[Explanation of symbols]

 3 Wave Sending Circuit 5 Wave Sending Focus Control Section 9 Overall Control Circuit

Claims (1)

[Claims] 1. A multi-stage focus type super-imaging method for setting a plurality of transmission focus points, transmitting ultrasonic pulses at different transmission timings according to the focus position, and displaying a diagnostic image based on the obtained sound ray data. In a sound wave diagnostic apparatus, a region setting unit for setting a display region of the diagnostic image, a focus point number setting unit for setting the transmission focus number, a display region set by the region setting unit, and Focus position setting means for setting focus positions corresponding to the number of focus points by the transmission focus points set by the focus point setting means, and aperture control for controlling the aperture according to the focus positions set by the focus position setting means. An ultrasonic diagnostic apparatus comprising: