JPH02215448A - Ultrasonic diagnostic device - Google Patents

Abstract

PURPOSE:To calculate and display quantitatively the scattering power of a tissue in an object to be measured by normalizing the tissue scattering power, which is calculated by a tissue scattering power calculating means, and calculating a scattering parameter according to blood scattering power, which is estimated by a blood scattering power calculating means, in the position of the tissue in the object to be measured. CONSTITUTION:Based on an ultrasonic signal reflected from the blood of an organ and the tissue of the object to be measured, a blood scattering power calculating means 6 calculates the blood scattering power from the blood in the organ and estimates the blood scattering power in the position of the tissue in the object to be measured by using the calculated scattering power. Then, a tissue scattering power calculating means 5 calculates the scattering power from the tissue of the object to be measured in the organ. A scattering parameter calculating means 7 normalizes (divides) the tissue scattering power, which is calculated by the tissue scattering power calculating means 5, according to the blood scattering power, which is estimated by the blood scattering power calculating means 6, in the position of the tissue in the object to be measured and calculates the scattering parameter.

Description

[Detailed Description of the Invention] [Summary] Calculates scattering parameters of a living body from received ultrasound signals.
Regarding the ultrasound diagnostic equipment that displays, the scattering power of the tissue to be measured can be quantitatively calculated by normalizing the scattering power of the tissue to be measured using the scattering power of blood. blood scattering power calculating means for calculating scattered power from blood in a living body; tissue scattering power calculating means for calculating scattered power from a tissue of a target to be measured in a living body; Estimating the blood scattering power at the position of the tissue to be measured from the blood scattering power calculated by the power calculating means, and normalizing the tissue scattering power calculated by the tissue scattering power calculating means using the estimated blood scattering power, a scattering parameter calculation means for calculating a scattering parameter of the tissue, and is configured to display the calculated scattering parameter of the tissue of the measurement target.

[Industrial application field]

The present invention relates to an ultrasonic diagnostic apparatus that calculates and displays scattering parameters of a living body from received ultrasonic signals. In recent years, diagnostic methods using ultrasound have increased the demand for improving diagnostic accuracy through more quantitative and qualitative diagnosis.The acoustic properties of tissues, especially attenuation and scattering properties, are used to express the quality of tissues. Attempts have been made to examine the quality of organizations based on differences. Here, the present invention relates to scattered power, which is one of the scattering characteristics among acoustic characteristics, that is, integrated backscat (IB) in the field of ultrasonic waves.
This relates to a method for quantitatively and accurately determining and displaying what is called ter).

[Prior art and the problem to be solved by the invention] Conventionally, when the scattered power of the heart wall was observed using ultrasound in synchronization with the heartbeat, the ultrasound scattered power was different between normal and infarcted areas. It is known that the degree of change in (IB) varies.

However, when actually diagnosing using ultrasound from the body surface, the ultrasound waves are attenuated considerably before reaching the measurement site, and the degree of attenuation varies from person to person, so the absolute amount of results obtained is There was a problem in that it did not necessarily accurately reflect the condition of the lesion. To solve this problem, a highly accurate measurement method for scattered power that does not depend on attenuation is required.

The present invention quantitatively calculates the scattered power of the tissue to be measured by normalizing the scattered power of the Mi tissue to be measured using the scattered power of blood with clear ultrasound scattering characteristics.
It is intended to be displayed.

[Means to solve problems]

Means for solving the problem will be explained with reference to FIG.

In FIG. 1, the blood scattering power calculation means 6 calculates the scattering power from blood in the living body, and uses it to estimate the blood scattering power at the position of the tissue of the measurement target.

The tissue scattering power calculation means 5 calculates the amount of the target to be measured in the living body!
This is to calculate the scattered power from Jl weave.

The scattering parameter calculating means 7 normalizes the tissue scattering power calculated by the tissue scattering power calculating means 5 by the blood scattering power at the position of the tissue of the measurement target estimated by the blood scattering power calculating means 6, and calculates the scattering parameter (
rB).

[Effect]

As shown in FIG. 1, in the present invention, the blood scattering power calculating means 6 calculates the scattering power from the blood in the living body based on the ultrasound signals reflected from the blood of the living body and the Mi tissue of the measurement target. Then, using this, the blood scattering power at the position of the tissue to be measured is estimated, the tissue scattering power calculating means 5 calculates the scattered power from the tissue of the measuring object in the living body, and the scattering parameter calculating means 7 calculates the scattered power from the tissue to be measured in the living body. Normalizing (dividing) the m-woven scattering power calculated by the tissue scattering power calculating means 5 by the blood scattering power at the position of the Mi-weave of the measured object estimated by the blood scattering power calculating means 6,
I am trying to calculate the scattering parameters.

Therefore, the blood scattering power at the position of the tissue to be measured is estimated from the scattering power of blood with clear ultrasound scattering characteristics, and the scattered power from the tissue of the measurement target is normalized by this estimated scattering power. By calculating the parameters, it becomes possible to quantitatively calculate and display the scattering parameter (IB) of the tissue.

〔Example〕

Next, the configuration and operation of one embodiment of the present invention will be explained in detail using FIGS. 1 to 7.

In FIG. 1, an ultrasonic probe 1 has an ultrasonic beam 1
) and receives the reflected waves.

The transmitting circuit 3 generates ultrasonic pulses according to predetermined timing. This generated ultrasonic pulse is amplified by the transmission amplifier 2, drives the ultrasonic probe I, and emits ultrasonic waves.

The reception amplifier 4 amplifies the signal received by the ultrasound probe 1.

The Mi fabric scattering power calculating means 5 calculates the scattering power of the ultrasonic waves reflected from the tissue region B in the figure.

The blood scattering power calculating means 6 calculates the scattering power of the ultrasonic waves reflected from the blood region A in the figure, and uses this to estimate the blood scattering power at the position of the tissue of the measurement target.

The scattering parameter calculating means 7 normalizes (divides) the tissue scattering power calculated by the tissue scattering power calculating means 5 by the blood scattering power at the position of the tissue of the measurement target estimated by the blood scattering power calculating means 6, and calculates the scattering This is to calculate the parameter (IB).

The ultrasonic image generation unit 8 generates known B-mode images, M-mode images, and the like.

The display device 9 is a display that displays the scattering parameters related to this embodiment calculated by the scattering parameter calculation means 7, B-mode images, M-mode images, electrocardiograms, and the like.

The Mi fabric 10 is the tissue to be measured according to this embodiment. &lI texture region B in this set mlO is the region for which scattering parameters are to be determined.

Blood region A is a region in which blood whose scattered power is known is flowing.

Figure 2 shows I B (Intergated Backs).
This is an explanatory diagram of the measurement method of (catter).

In FIG. 2(a), an ultrasonic beam 1) is emitted from an ultrasonic probe 1 as shown. Then, the scattered power from the blood reference site A where blood exists at the position of the depth Zl is calculated, and from this calculated scattered power, the scattered power at the depth Z3 is calculated.
Estimate the blood scattering power at . Furthermore, the scattered power from the tissue site B at the depth Z3 is calculated. Here, at the position of depth z2, a wall separating blood and tissue exists as shown in the figure. Next, from the scattering power of tissue part B at depth z3 and the blood scattering power at the position of depth Z3 estimated from the scattering power of blood at depth Zl, the scattering parameter of the tissue at the position of depth Z3 is calculated. The calculation will be explained using a formula.

The frequency characteristic of the transmitted ultrasound pulse is I(f), the scattered power from the tissue is P (2), and the scattered power from the blood is P
I(Z), the characteristics including the transmitting and receiving characteristics and sound field characteristics of the ultrasound probe are F(f, z), the round-trip attenuation characteristics up to depth 2 are A(f, z), and the scattering characteristics of blood are all , r', then
The blood scattering power at depth Zl is expressed as in the following formula (tl).

Pm (zl)□ f I(f)F(f, zl
) ^(f, zl) b I f' df・ ・
・ ・ ・ ・ ・ ・ (1) From the scattered power of this second full, the scattered power at depth Z3 can be approximately estimated as shown in the following equation.

P*(z3)=h(Zl) f G(f,
z3;zl) 8a (f, z2Hzl)A T
(f, z3; z2) df・ ・ ・ ・ ・ ・ (2)
Here, G (f, z3; zl) is the correction term for the sound field change between depth zl and depth z3 A s (f, z2.zl) is the correction term for the sound field change between depth zl and depth z2 The blood attenuation characteristic A T (f, z3; z2) is defined by the depth Z2 and the depth z3
is the attenuation property of the tissue between Therefore, ^(f, z3) =^(f, zl)8g (4, z
2; zl) A r (f, z3; z2) G (f, z3;
There is a relationship: zl)=F(f, z3)/F(f, zl).

In addition, the scattered power of the tissue at depth Z3 is calculated using the following formula (3
) can be expressed by

P r (z3)= , 1” I(f) F
(f, z3) A(f, z3) b 7 r 1Idf
・ ・ ・ ・ ・ ・ ・ ・ ・ (3) Here, when formula (3) is normalized by formula (2), the following formula (4) is obtained.

P(z3)=PT(z3)/P wealth(z3)...
(4) Here, equation (4) represents a tissue scattering parameter based on blood scattering power, which is referred to as IB in this embodiment.

FIG. 2(b) shows IB calculated using equation (4) as a temporal graph. Since the IB of this embodiment estimates the tissue scattering power using the blood scattering power, which has little individual difference, as a reference, the measured IB represents a highly accurate absolute value.

Therefore, compared to the conventional relative value of IB8 hydration ratio, the highly accurate IB8 hydration ratio
The absolute value of B can also be used for diagnosis.

FIG. 2(C) represents an electrocardiogram with the time axis aligned with FIG. 2(B).

FIG. 3 shows an explanatory diagram of m-liquid scattered waves.

FIG. 3(a) shows the correlating waves (received signal amplitude) from the parenchyma (tissue) and blood shown in FIG. 3(b). As is clear from this scattered wave, the power scattered from blood is considerably smaller than the power scattered from tissue. Also, large reflections often return from the wall between tissue and blood. For this reason, the effects of multiple reflections that occur in tissues overlap with the blood reflected waves, making it difficult to accurately calculate the blood scattering power.
Blood scattering parameters that are less affected by multiple reflections occurring in the parenchyma may be calculated by using the blood power determined by the Doppler detector 6-2.

FIG. 4 shows a configuration diagram of a specific example of the present invention.

In FIG. 4, the received signal 4-1 is transmitted to the ultrasound probe 1.
shows the signal received from.

The f-'' characteristic LPF 6-1 is a low-pass filter with f-'' characteristics. The scattering characteristics of blood are expressed as bl, where the frequency r and the scattering intensity (or differential scattering cross section) are
Since it is known that l f4, a signal having constant scattering characteristics with respect to frequency can be obtained by passing it through a filter having characteristics of f-4. still,
n may be set to another value.

The Doppler detector 6-2 is composed of a quadrature detector 6-2-1, an MTI filter, a blood flow velocity detection means 6-2-2, a power calculation means 6-2-3, etc. This calculates the scattered power.

The blood reference time interval detection means 6-3 detects a time interval (time phase) in which the blood velocity or blood scattering power exceeds the dark value (see FIG. 5).

6-4 compensates for variations in the scattered power from blood depending on blood flow velocity, or compensates for variations in blood scattered power due to variations in the volume fraction of red blood cells of the subject.

6-6 averages the scattered power of blood particles within the time interval detected by the blood reference time interval detection means 6-3 or the time interval designated by the external specification 6-5.

6-7 is an m-order interpolation of the scattered power from blood in a time phase where the blood flow is very slow and the scattered power from the blood cannot be obtained sufficiently (Figure 5 (e) is a linear interpolation. ).

6-8 is a correction means when changing the depth as shown in equation (2).

6-9 is for spatially averaging the power scattered from blood obtained between each scanning line.

5-1 is for calculating the scattered power from the tissue.

5-2 is for spatially averaging the scattered power from the tissue obtained in each scanning line.

7-1 specifies an ROI or marker as shown in blood reference site A and tissue site B in FIG. 1, or operates a function that causes the ROI or marker to follow wall motion.

7-2 is for calculating the scattering parameters described above.

7-3 is for correcting the amount by which the scattering parameter changes depending on the angle between the myocardial direction and the ultrasonic wave.

8-1 is information such as images and electrocardiograms from the ultrasonic diagnostic device.

9-1 performs display control.

9-2 is a display etc. for displaying information.

FIG. 5 shows an explanatory diagram of blood reference time intervals (time phases) and regions.

FIG. 5(a) shows the display area of the B-mode image, the area where blood scattering power can be calculated (Bl, B2), and the measurable tissue area (TI, T2, T3).

FIG. 5(b) shows an electrocardiogram.

In FIG. 5(c), both are displayed with markers added to the time interval in which the blood scattering power reaches a certain darkness value level or higher.

FIG. 5(d) shows the blood flow velocity and the time interval in which the blood flow velocity reaches a certain dark value level or higher with markers attached to display both.

The fifth (e) is obtained by linearly interpolating the section with scattered power as shown by the dotted line. This interpolation makes it possible to determine the scattering parameters of the tissue in all time phases.

FIG. 6 shows an example of displaying scattering parameters.

FIG. 6(a) shows the group 1) iT1 using the display area of the B-mode image and the blood scattering power of the blood reference areas B1 and B2.
, shows how the scattering parameters of the tissue of T2 are calculated.

FIG. 6(b) is an electrocardiogram.

FIG. 6(c) shows an example of how the scattering parameters of the tissues T1 and T2 change over time.

FIG. 6(d) shows blood reference temporal markers.

FIG. 6(E) shows an example in which scattering parameters are colored on the M-mode image. Here, FIGS. 6(A) to 2) are arbitrarily combined and displayed on the display.

FIG. 7 shows an example of displaying scattering parameters.

FIG. 7(a) shows an example in which scattering parameters are displayed in color on a B-mode image displayed by color Doppler.
The ROI representing the region is also displayed.

Although the color Doppler and scattering parameters are displayed simultaneously in this figure, they may be displayed on separate screens or only the scattering parameters may be displayed.

FIG. 7(b) shows a method for setting a marker in the myocardial direction with the B-mode image frozen, and correcting the angular dependence due to the angle formed with the scanning line direction. A correction coefficient is given, for example, as shown in FIG. 7(c).

FIG. 7(d) shows a profile of spatial tissue scattering parameters (IB) with reference to blood.

〔Effect of the invention〕

As explained above, according to the present invention, the blood scattering power at the position of the tissue of the measurement target is estimated from the scattering power of blood with clear ultrasound scattering characteristics, and the estimated blood scattering power is used to estimate the blood scattering power of the tissue of the measurement target. Normalize (divide) the scattered power from the tissue and calculate the scattering parameter (IB),
Since the display configuration is adopted, it is possible to remove the influence of attenuation and quantitatively estimate the tissue scattering parameter (IB>.Then, this estimated quantitative tissue scattering parameter can be displayed on the screen. This can be displayed together with B-mode images, electrocardiograms, etc. to improve diagnostic accuracy.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of one embodiment of the present invention, Fig. 2 is an explanatory diagram of the IB measurement method, Fig. 3 is an explanatory diagram of blood scattered waves, Fig. 4 is a configuration diagram of a specific example of the present invention, and Fig. 5 is an explanatory diagram of blood reference time intervals (time phases) and regions, and FIGS. 6 and 7 are display examples of scattering parameters. In the figure, 1 is an ultrasound probe, 5 is a tissue scattering power calculation means, 6 is a blood scattering power calculation means, 6-2 is a Doppler detector, 6-3 is a blood reference time interval detection means, and 7.7-2 is a blood scattering power calculation means. The scattering parameter calculation means, 9 represents a display device.

Claims (4)

[Claims] (1) In an ultrasound diagnostic apparatus that calculates and displays scattering parameters of a living body from received ultrasound signals, a blood scattering power calculation means (
6), a tissue scattered power calculation means (5) for calculating the scattered power from the tissue of the object to be measured in the living body, and a blood scattering power calculation means (6) for calculating the scattered power of the object to be measured from the blood scattering power calculated by the blood scattering power calculation means (6). Scattering parameter calculation means (5) that estimates the blood scattering power at the position of the tissue, normalizes the tissue scattering power calculated by the tissue scattering power calculation means (5) using the estimated blood scattering power, and calculates the scattering parameter of the tissue. 7), and is configured to display the calculated scattering parameter of the tissue of the object to be measured. (2) In claim (1), an average of the blood scattering power is calculated for a time interval in which the blood scattering power exceeds a threshold level, and the calculated blood scattering power is used to calculate the scattering of the tissue of the object to be measured. An ultrasonic diagnostic device characterized by being configured to calculate and display parameters. (3) Mark (or color) the area and time interval where the blood flow velocity or blood flow power is above the threshold level
Claim No. (
The ultrasonic diagnostic apparatus described in item 1) and item (2). (4) The ultrasonic diagnostic apparatus according to any one of claims (1) to (3), characterized in that the estimated tissue scattering parameter is displayed as a graph that changes over time.