JP3866368B2 - Ultrasonic diagnostic equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ultrasonic diagnostic apparatus that scans the inside of a subject with ultrasonic waves and generates and displays an ultrasonic image based on an obtained echo signal.
[0002]
[Prior art]
There are various devices for medical applications of ultrasound, and the mainstream is an ultrasound diagnostic device for tomographic images of soft tissue of a living body using an ultrasonic pulse reflection method. This ultrasonic diagnostic apparatus is a non-invasive examination method and displays a tomographic image of a tissue. Compared to other diagnostic apparatuses such as an X-ray diagnostic apparatus, an X-ray CT apparatus, an MRI, and a nuclear medicine diagnostic apparatus, It has unique features such as display capability, small size, low cost, high safety without exposure to X-rays, and blood flow imaging by ultrasonic Doppler method.
[0003]
For this reason, the application range is wide in the heart, abdomen, mammary gland, urology, and gynecology. In particular, a simple operation that simply assigns an ultrasound probe from the body surface provides a real-time display of heart beats and fetal movements, and because it is highly safe, it can be repeatedly examined and moved to the bedside. Therefore, it is easy to carry out inspections.
[0004]
In this way, there are various advantages of ultrasonic diagnosis, but in recent years, it is equipped with a function to measure the size of fetuses, lesions, organs, etc. by the distance between two points, the perimeter, the area, etc. However, its usefulness is increasing.
[0005]
By the way, in the measurement function described above, for example, distance measurement between two points, a caliper for measurement called a caliper is displayed superimposed on the ultrasonic image. This caliper moves on the screen according to the movement of the trackball, etc. The operator simply positions the caliper on the measurement target part and then calculates on the device side. Yes.
[0006]
In this caliper alignment, first, one end point (hereinafter referred to as “fulcrum”) of the caliper is fixed at a desired position. Then, the other end point (hereinafter referred to as “play point”) is moved to the diagonal of the region to be measured and confirmed. While moving the play point, the caliper expands and contracts following the movement, so you can see which distance to measure.
[0007]
By the way, this measurement accuracy depends on how the fulcrum and the play point are accurately aligned with the measurement target part. When the measurement target part is captured largely on the ultrasonic image, it is considered that alignment is relatively easy and a certain degree of measurement accuracy can be maintained.
[0008]
However, when the measurement target region is only small on the ultrasonic image, it is difficult to align the position and sufficient measurement accuracy cannot be maintained.
[0009]
Further, the fulcrum and play point markers are displayed in a certain size in consideration of easy viewing. For this reason, if the measurement target part is too small, it becomes difficult to see because it is hidden behind the fulcrum or play point marker, resulting in a further reduction in measurement accuracy.
Further, similar to the S / N relationship, the smaller the measurement target portion, the greater the influence of the error.
[0010]
[Problems to be solved by the invention]
An object of the present invention is to provide an ultrasonic diagnostic apparatus capable of improving measurement accuracy.
[0011]
[Means for Solving the Problems]
The present invention displays an elastic measurement caliper on an ultrasonic image obtained based on an echo signal obtained by scanning the inside of a subject with ultrasonic waves, and measures quantitative information according to the caliper. In the ultrasonic diagnostic apparatus, when the length of the caliper becomes shorter than a predetermined length, the ultrasonic image is enlarged and displayed.
[0013]
(Function)
In the present invention, when the length of the caliper becomes shorter than the predetermined length, the ultrasonic image is enlarged and displayed. This eliminates a decrease in measurement accuracy due to the fact that the measurement target part is small on the ultrasonic image and it is difficult to match the measurement tool.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an ultrasonic diagnostic apparatus according to the present invention will be described with reference to the drawings according to preferred embodiments. FIG. 1 shows the configuration of an ultrasonic diagnostic apparatus according to this embodiment. This apparatus uses a central control circuit (not shown) as a system center, an ultrasonic probe 2, a transmission unit 3, a reception unit 4, and a B-mode processing unit for generating a B-mode (tomographic image) image from echo signals. 5, a color Doppler processing unit 9 for generating a color Doppler mode (blood flow image) image from the echo signal, an image recording unit 6, a display unit 7, and a measurement unit 8. For convenience of explanation, only the processing units 5 and 9 for the B mode and the color Doppler mode are shown here, but other mode processing units such as the M mode, continuous wave Doppler mode, and pulse wave Doppler mode are appropriately combined. May be equipped. Since the configuration of these processing units may be a conventionally known one, description thereof will be omitted here.
[0016]
The ultrasonic probe 2 has a plurality of micro piezoelectric elements arranged at the tip portion in order to mediate between the side that handles electrical signals and the subject side that imparts internal information to the ultrasonic waves. The form of the probe 2 is arbitrarily selected from among sector correspondence, linear correspondence, convex correspondence, and the like.
[0017]
The transmission unit 3 for transmitting ultrasonic waves from the ultrasonic probe 2 includes a clock generator 31, a rate pulse generator 32, a transmission delay circuit 33, and a pulsar 34. A rate pulse for determining an ultrasonic transmission rate (number of transmissions per second) is output from the rate pulse generator 32 in accordance with the clock oscillated from the clock generator 31. The rate pulse receives an appropriate delay necessary for determining the directivity of the ultrasonic wave by the transmission delay circuit 33 and is given to the pulser 34 as a trigger pulse. In synchronization with the trigger pulse, a high-frequency signal pulse is applied from the pulser 34 to the piezoelectric element of the probe 2 individually or in units of neighboring groups. The piezoelectric element of the probe 2 vibrates in response to this signal pulse. Thereby, an ultrasonic wave is generated and transmitted to the subject.
[0018]
This ultrasonic wave propagates in the living body, and is reflected one after another at a discontinuous surface of acoustic impedance in the middle. This reflection intensity mainly depends on the difference in acoustic impedance of the discontinuous surface. Ultrasound is also reflected by the heart wall and blood cells, but the reflection by these moving bodies includes a frequency shift due to the Doppler effect.
[0019]
The echo due to such reflection returns to the probe 2 and vibrates the piezoelectric element. As a result, a weak electric signal is generated from the piezoelectric element. This electric signal is taken into the receiving unit 4. The reception unit 4 includes a preamplifier 41, a reception delay circuit 42, and an adder 43. The electrical signal from the probe 2 is first amplified by the preamplifier 41, and after receiving an appropriate delay opposite to that at the time of transmission by the reception delay circuit 42, for example, is added by an adder. As a result, one echo signal having reception directivity is acquired.
[0020]
This echo signal is sent to the B-mode processing unit 5 and the color Doppler processing unit 9, respectively. The B mode processing unit 5 includes a detection circuit 51, a logarithmic amplifier 52, and an analog / digital converter (A / D) 53. The detection circuit 51 detects the echo signal and outputs its envelope. This output signal is logarithmically amplified by a logarithmic amplifier 52 and further converted into a digital signal by an analog-digital converter 53 before being output.
[0021]
The color Doppler processing unit 9 includes a mixer 91, a low-pass filter 92, an analog / digital converter (A / D) 93, an MTI filter 94, an autocorrelator 95, and a calculation unit 96. The mixer 91 and the low-pass filter 92 constitute a quadrature phase detection circuit, and a reference signal having the same center frequency as the transmission frequency and a reference signal shifted by 90 ° are individually multiplied by the echo signal, and this multiplication is performed. By removing the high frequency component from each of the signals obtained by the above, a shift frequency component is taken out and output as a Doppler signal. The Doppler signal includes a high-frequency component that has undergone a frequency shift mainly due to reflection from a fast moving body such as blood cells, and a low-frequency component that has undergone a frequency shift mainly due to reflection from a slow moving body such as a heart wall. Frequency component.
[0022]
The Doppler signal is sampled by the analog-digital converter 63 according to a predetermined sampling frequency corresponding to, for example, an interval of 0.5 mm for one scanning line, converted into a digital signal, and sent to the MTI filter 64.
[0023]
The MTI filter 64 functions as a high-pass filter, passes only high-frequency components (blood flow components) that have undergone frequency shift mainly due to reflection by a fast moving body such as blood cells, and is mainly a slow moving body such as a heart wall. The low-frequency component (clutter component) that has undergone frequency shift due to reflection at is removed. Then, the Doppler signal including only the blood flow component is subjected to frequency analysis by the autocorrelator 65 to obtain a deviation frequency due to blood cells. Based on this deviation frequency, the calculation unit 66 calculates the blood flow velocity (average velocity), its variance, and the power (amplitude of the Doppler signal) that mainly reflects the blood flow for each sample point. .
[0024]
The B-mode signal and the blood flow signal are sent to the display unit 7 for display, and simultaneously sent to the image recording unit 6 to be recorded on a storage medium such as a memory or a magnetic disk.
[0025]
The display unit 7 includes a display image control circuit 71, a memory 72 that functions as a buffer, an echo image / graphics mixing circuit 73, and a TV monitor 74. The display image control circuit 71 has a function as a digital scan converter (DSC), and B mode and color Doppler sent directly from the B mode processing unit 5 and the color Doppler processing unit 9 in real time. Image signal (hereinafter referred to as “echo image signal”) or an echo image signal sent in non-real time from the image recording unit 6 at the time of reproduction is converted into a TV scanning method and output. The echo image signal converted into the TV scanning method is sent to the echo image / graphics mixing circuit 73 via the memory 72, where it is mixed with graphics such as a measurement tool (caliper), and is sent to the TV monitor 74. Is displayed.
[0026]
Next, the characteristic measurement unit 8 of this embodiment will be described. This measurement unit 8 is activated by a command input when an operator desires to measure the size of a fetus, a lesioned part, an organ, or the like with a distance between two points, a peripheral length, an area, or the like. An in-unit control circuit 81 under control of the central control circuit, a trackball 82, a caliper control circuit 83, a trackball 84, an ROI control circuit 85, an arithmetic circuit 86, a graphics control circuit 87, The two track balls may be excluded by switching the function, or may be a coordinate input device such as a mouse or a digitizer.
[0027]
In the measurement function as described above, for example, distance measurement between two points, the graphics of a marker called a caliper having a meaning as a caliper for measurement is created by the graphics control circuit 87, and the echo image / graphic is sent via the memory 88. The ultrasonic image is mixed with the ultrasonic mixing circuit 73 and displayed on the TV monitor 74 so as to be superimposed on the ultrasonic image.
[0028]
The caliper can be freely moved on the screen following the movement of the trackball 82 under the control of the caliper control circuit 83, and can be arbitrarily expanded and contracted. Then, the operator simply moves the trackball 82 and positions (positions) the measurement target part, and then the operation circuit 86 on the apparatus side automatically calculates the distance between the two points. .
[0029]
In the measurement unit 8, the operator can freely specify the measurement area, and the graphic of the rectangular ROI marker for designating the measurement area is created by the graphics control circuit 87, and is stored in the memory 88. Is mixed with the ultrasonic image by the echo image / graphics mixing circuit 73 and displayed on the TV monitor 74 so as to be superimposed on the ultrasonic image. This ROI can be moved freely on the screen following the movement of the trackball 84 under the control of the control circuit 85, and the size can be freely changed.
[0030]
First, the operator moves the trackball 84 to fix the ROI fulcrum near the site to be measured. Then, when the trackball 84 is further moved to move the diagonal point (play point), the size of the ROI changes in real time. The operator confirms the state in which the ROI appropriately includes the measurement target part and determines the play point. Thereby, the ROI, that is, the measurement area is also determined.
[0031]
FIG. 2 shows an example of a display screen after the measurement area is determined. When the measurement area is determined, the in-unit control circuit 81 controls the display image so that a part (partial image) of the ultrasonic image surrounded by the ROI is enlarged and displayed in a window at a predetermined position on the screen. The circuit 71 is controlled. This enlargement can be realized by selective reading of an echo image temporarily stored in the display image control circuit 71 and interpolation. The intra-unit control circuit 81 controls the graphics control circuit 87 so that calipers are displayed on the enlarged partial image.
[0032]
When the measurement area is specified in this way, the partial image in the area is enlarged and displayed, so that the reduction in measurement accuracy due to the fact that the measurement target part is small on the ultrasonic image and it is difficult to align the calipers is eliminated. .
[0033]
After the measurement is performed using such an automatic enlargement function and the measurement is completed, an enlarged image erasure signal is supplied from the in-unit control circuit 81 to the memory 72, and the display of the enlarged image is terminated. It automatically returns to the display so that repeated measurements can be made easily.
[0034]
Next, the caliper positioning will be described. In order to align the caliper, as shown in FIG. 3, first, the operator moves the trackball 82 to set one end point of the caliper (hereinafter referred to as “fulcrum”) to a desired position of the measurement target region. (See FIG. 4).
[0035]
Then, the trackball 82 is further moved, and the other end point (hereinafter referred to as “play point”) is moved to the diagonal of the measurement target part. While the play point is moved, the caliper expands and contracts following the movement.
[0036]
The length of the caliper is monitored from time to time by the in-unit control circuit 81. When the caliper length becomes shorter than a predetermined length, the in-unit control circuit 81 controls the display image control circuit 71 to generate ultrasonic waves. The image display is switched to the enlarged display so that the position of the fulcrum on the caliper screen does not change before and after the enlargement. This enlargement can also be realized by selective reading of an echo image temporarily stored in the display image control circuit 71 and interpolation.
[0037]
The operator moves the trackball 82 to accurately align and confirm the play point on the enlarged image at the desired position. When the caliper is determined in this way, that is, when two points are determined, the distance between the two points is converted into an actual size by the arithmetic circuit 86 and displayed on the TV monitor 74.
[0038]
After the measurement is performed using the automatic enlargement function and the measurement is completed, the control signal for returning the display scale to the display image control circuit 71 is supplied from the in-unit control circuit 81 to display image control. The circuit 71 can reset the data in the memory 72 so that repeated measurement can be easily performed.
[0039]
When the length of the caliper is shorter than the predetermined length in this way, the ultrasonic image is enlarged and displayed, so the measurement accuracy is reduced due to the measurement target area being small on the ultrasonic image and the caliper being difficult to align. Is resolved. In addition, since the position of the fulcrum on the caliper screen does not move before and after the enlargement, the operator is less likely to be dazzled.
It goes without saying that the present invention is not limited to the above-described embodiments and can be implemented with various modifications.
[0040]
【The invention's effect】
In the present invention, when a measurement area is designated on an ultrasonic image, a partial image in the designated measurement area is enlarged and displayed together with a measurement tool. This eliminates a decrease in measurement accuracy due to the fact that the measurement target part is small on the ultrasonic image and it is difficult to match the measurement tool.
[0041]
In the present invention, when the length of the caliper becomes shorter than a predetermined length, the ultrasonic image is enlarged and displayed. This eliminates a decrease in measurement accuracy due to the fact that the measurement target part is small on the ultrasonic image and it is difficult to match the measurement tool.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of an ultrasonic diagnostic apparatus according to a preferred embodiment of the present invention.
2 is a diagram showing an example of a display screen that is automatically switched after setting a rectangular ROI for limiting a measurement range under the control of the in-unit control circuit of FIG. 1;
3 is a flowchart showing a procedure for screen switching control by control of an in-unit control circuit of FIG. 1 in accordance with a caliper operation for measuring a distance between two points.
4 is a diagram showing an example of a display screen for supplementing the screen switching operation of FIG. 3;
FIG. 5 is a diagram showing an example of a conventional display screen for measuring a distance between two points.
[Explanation of symbols]
2 ... ultrasonic probe,
3 ... Ultrasonic transmission unit,
4 ... Ultrasonic receiver unit,
5 ... B-mode processing unit,
6 ... Image recording unit,
7 ... Display unit,
8 ... Measurement unit,
31 ... clock generator,
32. Rate pulse generator,
33 ... transmission delay circuit,
34 ... Pulsa,
41 ... Preamplifier,
42. Reception delay circuit,
43 ... adder,
51. Detection circuit,
52... Logarithmic amplifier,
53. Analog-digital converter,
71 ... Display image control circuit,
72 ... Memory,
73 ... Echo image / graphics mixing circuit,
74 ... TV monitor,
81. In-unit control circuit,
82 ... Trackball,
83 ... caliper control circuit,
84 ... Trackball,
85 ... ROI control circuit,
86: arithmetic circuit,
87: Graphics control circuit,
88 ... Memory.

Claims (2)

  In an ultrasonic diagnostic apparatus that displays an elastic measurement caliper on an ultrasonic image obtained based on an echo signal obtained by scanning the inside of a subject with ultrasonic waves, and measures quantitative information according to the caliper An ultrasonic diagnostic apparatus that enlarges and displays the ultrasonic image when the length of the caliper becomes shorter than a predetermined length.   The ultrasonic diagnostic apparatus according to claim 1, wherein before and after the enlargement, the display is switched to an enlarged display so that a specific point of the caliper does not move on the screen.

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