JPS6379641A - Ultrasonic diagnostic apparatus - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to an ultrasonic diagnostic apparatus that is effective for determining tissue properties of a living body.

(b) Prior art and its problems Generally, in an ultrasound diagnostic device, an ultrasound beam is emitted from a transducer, and the reflected ultrasound echoes are returned to the transducer according to the difference in acoustic impedance between media within the living tissue. A B-mode image (ultrasound tomographic image) based on the echo signal data obtained is displayed on a CRT.
display on a monitor such as

Incidentally, the intensity value of a reflected echo obtained by emitting an ultrasound beam corresponds to the acoustic impedance characteristics of tissue within the subject. Therefore, data obtained by statistically processing each intensity value directly provides information on tissue properties, and effective use of this data can aid in diagnosis.

Therefore, the present inventors created a histogram for a normal area and a lesion area based on echo signal data obtained by transmitting and receiving an ultrasound beam, and provided a method for calculating the difference between the two histograms. (Special application 1986-8
6946).

The present inventors further studied this method and found that
It has been found that depending on the tissue of the subject, the difference between a lesioned area and a normal area may not be clear simply by calculating the difference in histograms, and therefore it may be difficult to distinguish between the two.

The present invention has been made in view of the above circumstances, and it is possible to clearly distinguish the difference in tissue properties such as a normal part and a diseased part from echo signal data based on transmission and reception of ultrasonic waves. The purpose is to further facilitate the determination of tissue properties.

(c) Means for solving the problem When external pressure above a certain value is applied to a living body, the part to which the external pressure is applied is compressed and not only the density changes, but also the microstructure of that part changes. Therefore, when an ultrasonic beam is irradiated with external pressure applied, the state of scattering in that area changes. Since the degree of change varies depending on the tissue properties, information on the tissue properties can be obtained by statistically processing the echo signal data obtained under the above conditions.

The present invention focuses on this point and has the following configuration. That is, the ultrasonic diagnostic apparatus of the present invention includes: a B-mode display transducer that linearly scans an object with ultrasonic waves; a pump wave transducer that generates a pump wave that applies external pressure to the object; and the B-mode display transducer that generates a pump wave that applies external pressure to the object. Independent drive of display transducer and B
a control circuit that outputs a control signal for selecting simultaneous driving of the mode display transducer and the pump wave transducer; and an image memory that stores echo signal data obtained by the B mode display transducer in the presence or absence of the pump wave. and a histogram creation circuit that creates a histogram for each echo signal data stored in the image memory with and without the pump wave.

(d) Function In the ultrasonic diagnostic apparatus of the present invention, the B-mode display transducer is first driven independently by a control signal output from the control circuit, and the ultrasonic beam linearly scans the subject. Through this linear scanning, the B-mode display transducer obtains echo signal data based on reflected echoes from the subject, and this echo signal data is stored in the image memory.

Next, the B-mode display transducer and the pump wave transducer are simultaneously driven by a control signal from the control circuit. As a result, the B-mode display transducer obtains echo signal data in a state in which external pressure due to the pump wave is applied to the subject, and this echo signal data is stored in the image memory in the same manner as described above.

When a pump wave is transmitted to a subject, the part to which the pump wave is applied is not only compressed and the density changes, but also the fine structure of that part changes, causing a change in the scattering behavior. The degree of change shows specificity depending on tissue properties. Therefore, each echo signal data with and without the pump wave stored in the image memory is read out, and a histogram of each echo signal data with and without the pump wave is created in a histogram creation circuit, respectively.

The shape of the histogram changes differently depending on whether there is a pump wave or not, and the extent of the change depends on the tissue properties, so tissue properties can be determined by comparing and observing the histograms with and without each pump wave for each region. . Furthermore, by calculating the difference between the histograms with and without the pump wave and displaying the distribution shape of this difference, it is possible to understand the difference in tissue properties more clearly.

(e) Embodiment FIG. 1 is a block diagram of an ultrasonic diagnostic apparatus according to an embodiment of the present invention. In the same figure, reference numeral 1 indicates the entire ultrasonic diagnostic apparatus, 2 is a subject, 4 is a B-mode display transducer that linearly scans the subject 2 with ultrasonic waves,
Reference numeral 6 denotes a pump wave transducer that generates a pump wave for external application to the subject 2.

8 is a first pulser that outputs a driving pulse to the B-mode display transducer 4, 10 is a second pulser that outputs a driving pulse to the pump wave transducer 6, and 12 is an 11th second pulser 8.10. A wave transmitting circuit 14 outputs a wave transmitting signal, and 14 independently drives the B mode display transducer 4 for the wave transmitting circuit 12.
This is a control circuit that outputs a control signal for selecting simultaneous driving of the mode display transducer 4 and the pump wave transducer 6, and is composed of, for example, a CPU.

16 is a receiving circuit that amplifies and detects the echo signal output from the B-mode display transducer 4; 18 is a receiving circuit for the echo signal that has passed through the receiving circuit 16; STC adjusted according to
An adjustment circuit 20 is a level adjustment circuit that compensates for changes in the amplitude of the ultrasound beam when a pump wave is applied to the subject 2, and 22 is an A/
This is an A/D converter that performs D conversion.

26 is an image memory for storing echo signal data obtained from the B-mode display transducer 4 with and without a pump wave; 28 is an image memory for each echo signal data stored in the image memory 26 with and without a pump wave; 30 histogram creation circuits each creating a histogram;
is a difference calculation circuit that calculates the difference between each histogram with and without a pump wave created by the histogram creation circuit 28;
32 is a D/A converter that converts data read from the image memory 26 into analog, and 34 is a color monitor.

Next, the operation of the ultrasonic diagnostic apparatus I having the above configuration will be explained.

In the ultrasonic diagnostic apparatus l of the present invention, as shown in FIG.
B-mode images are obtained under the first image area in the absence of pump waves and the second image area in the presence of pump waves. To do this, first, a control signal output from the control circuit I4 causes the wave transmission circuit 12 to output a wave transmission signal to the B-mode display transducer 4.
This transmission signal is applied to the first pulser 8. Then, the first
A drive pulse is output from the pulser 8, and this drive pulse is applied to the B-mode display transducer 4. As a result, the B-mode display transducer 4 is driven independently, and the object 2 is linearly scanned with an ultrasound beam. By this linear scanning, the B-mode display transducer 4 outputs an echo signal based on the reflected echo from the subject 2. After this echo signal is amplified and detected by the wave receiving circuit 16, its gain is time-adjusted by the STC adjustment circuit 18. In this case, level adjustment circuit 2
Since 0 is not activated, the echo signal is sent to level adjustment circuit 2.
After passing through 0 as is and being A/D converted by the A/D converter 22, it is stored in the image memory 26.

When external pressure is applied to the object 2, if this external pressure exceeds a certain level, the area to which the external pressure is applied will not only be compressed and its density will change, but also the fine structure of that area will change, causing the state of scattering to change. Change. Therefore, when a pump wave is transmitted to the subject 2, as shown in Figure 3, if the sound pressure is above a certain level δ, the ultrasound is transmitted and received with the pump wave added. The amplitude of the obtained echo signal becomes nonlinear. The state of the change shows specificity depending on the tissue properties.

Therefore, next, in response to the control signal output from the control circuit 14, the wave transmission circuit 12 outputs a wave transmission signal that simultaneously drives the B-mode display transducer 4 and the pump wave transducer 6. This transmission signal is simultaneously applied to the eleventh and second pulsers.

Then, the first. Drive pulses are output from the second pulsers 8 and 10, respectively, and each drive pulse is applied to the B-mode display transducer 4 and the pump wave transducer 6 at the same time. As a result, an echo signal is obtained from the B-mode display transducer 4 when external pressure is applied to the subject 2, and this echo signal passes through the wave receiving circuit 6 and the STC adjustment circuit 18 to the level adjustment circuit. 20
is input. The level adjustment circuit 20 adjusts the amplitude change of the ultrasonic beam due to the pump wave to the level of the amplitude change without the pump wave, and outputs the adjusted level. Bell adjustment circuit 2
The echo signal level-adjusted at 0 is sent to the A/D converter 22.
After being A/D converted, the image is stored in the image memory 26.

The control circuit 14 allows the B-mode display transducer 4 to perform linear scanning once by itself, and then immediately switches to linear scanning with a pump wave added. The time from image formation to B-mode image formation for one frame when a pump wave is present is about 1/30 sec.

When each echo signal data with and without a pump wave is stored in the image memory 26, the control circuit 14 reads out this echo signal data in synchronization with the TV signal, and reads it out from the D/A converter 3.
After D/A conversion in step 2, the data is output to the color monitor 34.

In this way, as shown in Figure 4, when there is no pump wave (
Each B-mode image is displayed in (a) of the same figure and when present ((b) of the same figure).

Therefore, next, regions of interest RO1, ,ROI are set for the same part of both B-mode images, and the control circuit 14
Therefore, the echo signal data included in the regions of interest Rot, ROIt are not read out from the image memory 26. Then, these data are sent to the histogram creation circuit 28. In the histogram creation circuit 28, each region of interest RO1
, ,ROI,, the number of pixels for each signal intensity level of the echo signal data included in the echo signal data is integrated to create a histogram with the horizontal axis as the signal intensity level and the vertical axis as the frequency (fifth
(see figure).

The shape of the histogram is different between when there is no pump wave (FIG. 5(a)) and when there is a pump wave (FIG. 5(b)), and the extent of the difference differs depending on the tissue properties. Therefore, the data of each histogram with and without a pump wave created by the histogram creation circuit 28 is sent to the difference calculation circuit 30 to calculate the difference between the two histograms.

This difference is as shown in FIG. 6, for example, and its distribution shape shows specificity depending on tissue properties.

Therefore, by storing this difference data in the image memory 26 and then reading it out and displaying it on the color monitor 34, it becomes possible to determine the tissue properties, such as whether it is a normal area or a diseased area, from the displayed distribution shape. .

In addition, in this embodiment, the pump wave transducer 6
is provided separately from the B-mode display transducer 4, but it is also possible to use the B-mode display transducer 4 alone and generate a pump wave by changing the power of its ultrasonic waves. In addition, if the tissue properties have directionality, if each histogram is created by changing the position of the pump wave transducer 6 and changing the transmission direction of the pump waves to the tissue subject 2, the directionality of the tissue properties can be adjusted. You can also compare the differences.

(f) Effects As described above, according to the present invention, echo signal data is obtained for both cases with and without pump waves, and a histogram is created based on both data.
By calculating the difference between both histograms and displaying the B-mode image for each color based on the difference data, excellent effects such as information useful for diagnosis of tissue properties can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an ultrasonic diagnostic apparatus according to an embodiment of the present invention, Fig. 2 is a timing chart of pump waves, Fig. 3 is a characteristic diagram showing the relationship between sound pressure and amplitude, and Fig. 4 is a pump wave diagram. FIG. 5 is a diagram showing a histogram created from echo signal data displaying each B-mode image in FIG. 4.
FIG. 6 is a characteristic diagram obtained by subtracting the two histograms shown in FIG. l...Ultrasonic diagnostic device, 4...B-mode display transducer, 6...pump wave transducer,
14... Control circuit, 26... Image memory, 28...
-Histogram creation circuit.

Claims (1)

[Claims] (1) A B-mode display transducer that linearly scans the object with ultrasonic waves, a pump wave transducer that generates a pump wave that applies external pressure to the object, and independent driving of the B-mode display transducer; B
a control circuit that outputs a control signal for selecting simultaneous driving of the mode display transducer and the pump wave transducer; and an image memory that stores echo signal data obtained by the B mode display transducer in the presence or absence of the pump wave. and a histogram creation circuit that creates a histogram for each echo signal data stored in the image memory with and without the pump wave.