JPH03247328A - Ultrasonic diagnosing apparatus - Google Patents

Abstract

PURPOSE:To enable the improving of an S/N ratio by arranging a blood flow data processing section, a power limit value generation circuit, a dispersion limit value generation circuit and a power limiter circuit to allow the removal of noise components, for example, caused by a flap and wall of a heart. CONSTITUTION:A power limit value generation circuit 30 generates a specified power limit value according a velocity of a blood flow obtained at a blood flow data processing section 4. A dispersion limit value generation circuit 31 generates a specified dispersion limit value according to the velocity of the blood flow obtained at the blood flow data processing section 4. Then, when an intensity of a blood flow signal is larger than the power limit value while being smaller than the dispersion limit value, an output of the blood flow data processing section is cut with a power limiter circuit 24. For example, the power limit value with the power limit value generation circuit 30 is set higher while the dispersion limit value with the dispersion limit value generation circuit 31 is set lower thereby enabling reduction in noise components caused by motions of a flap and a wall of a heart.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an ultrasonic diagnostic device, and particularly, to emitting an ultrasonic beam into a living body and detecting blood flow in the living body based on a fouling signal obtained inside the living body. The present invention relates to an ultrasonic diagnostic device that displays information.

[Conventional technology]

Ultrasonic diagnostic equipment used in the medical field, for example, displays tomographic data of the heart on a real tight monitor, or measures blood flow velocity in a specific region using the pulse Doppler method, and monitors this distribution in the same way as described in 011. It is common practice to display the Furthermore, there is a system in which tomographic data is displayed on a single screen, and the blood flow velocity of a specific region is displayed side by side on the monitor on which the tomographic data is displayed.

Recently, in order to understand the blood flow velocity two-dimensionally, two
A dimensional blood flow tomography method is adopted. This combines blood flow velocity with tomographic data and expresses blood flow velocity two-dimensionally and in real time. That is, the tomographic information and blood flow information are each digitized and combined, converted into R, G, and B television signals, and the blood flow velocity is displayed superimposed on the normal tomographic image. The average velocity profile of the detected blood flow is displayed in color (color flow mapping).

In such ultrasonic diagnostic equipment, in order to remove noise components from obtained blood flow data, MT l
(Moving Target Indication
n> A filter and power limiter circuit is provided.

The MTI filter is a bypass filter that removes noise components by removing low frequency components. The power limiter circuit is for removing random noise components by removing components with low power.

[Problem to be solved by the invention]

The reflected echoes also include signal components due to the movement of the heart valves and walls, and the movements of the heart valves and walls vary over a wide range from fast to slow components.

Therefore, there is a problem in that relatively fast movements cannot be removed even through an MTI filter.

By the way, as a result of intensive research by the inventor of the present invention, it has been found that the movements of the heart valves and walls have many components characterized by strong power and low dispersion at any speed. On the other hand, there are almost no components with strong power and low dispersion in the bloodstream components. Therefore, it is considered that by removing these components, noise components coming from the heart valves, walls, etc. can be removed.

An object of the present invention is to provide an ultrasonic diagnostic apparatus that can remove noise components coming from, for example, heart valves and walls, and can improve the S/N ratio.

[Means to solve the problem]

The ultrasonic diagnostic apparatus according to the present invention includes a blood flow data processing section,
It includes a power limit value generation circuit, a distributed limit value generation circuit, and a power limiter circuit. The blood flow data processing section is for obtaining in-vivo blood flow data based on reflected signals obtained in the living body. The power limit value generation circuit is a circuit that generates a predetermined power limit value according to the blood flow velocity obtained by the blood flow data processing section. The dispersion limit value generation circuit is a circuit that generates a predetermined dispersion limit value according to the blood flow velocity obtained by the blood flow data processing section. The power limiter circuit is
This circuit cuts off the output signal from the blood flow data processing section when the intensity of the blood flow signal is larger than the power limit value and smaller than the dispersion limit value.

[Effect]

In the ultrasonic diagnostic apparatus according to the present invention, first, the blood flow data processing section obtains in-vivo blood flow information based on a reflected signal obtained from within the living body. The power limit value generation circuit generates a predetermined power limit value according to the blood flow velocity obtained by the blood flow data processing section. Further, the dispersion limit value generation circuit generates a predetermined dispersion limit value according to the blood flow velocity obtained by the blood flow data processing section. Then, the power limiter circuit cuts off the output signal of the blood flow data processing section when the intensity of the blood flow signal is greater than the power limit value and smaller than the dispersion limit value.

For example, by setting the power limit value of the power limit value generation circuit to a high value and setting the dispersion limit value of the dispersion limit value generation circuit to a low value, noise components resulting from the movement of the heart valves and walls can be reduced. This allows the S/N ratio to be improved.

〔Example〕

FIG. 4 shows a schematic configuration of an ultrasonic diagnostic apparatus according to an embodiment of the present invention.

In FIG. 4, an ultrasonic probe 1 is composed of a plurality of microscopic transducers, and is connected to a transmitting/receiving circuit 2. As shown in FIG.

The transmitting/receiving circuit 2 includes a high frequency pulse oscillator 1 for transmitting an ultrasonic beam, a receiver for receiving and processing reflected echoes, a delay circuit for performing electronic scanning, a delay amount selection circuit, and the like. The output of the transmitting/receiving circuit 2 is connected to a tomographic data processing system 3 and a blood flow data processing system 4.

The tomographic data processing system 3 is a circuit for obtaining tomographic data of a living body. The tomographic data processing system 3 includes a receiving wave shaping circuit 5 that performs waveform shaping processing on the received signal, and an A/D converter 6 that converts the output signal into a digital signal.

A display signal generation circuit 11 including a DSC (digital scan converter) is connected to the output of the A/D converter 6.

Further, the blood flow data processing system 4 is a circuit for obtaining blood flow data of a living body based on the Doppler shift frequency. The blood flow data processing system 4 includes a delivery shaping and detection circuit 7 for performing waveform shaping and detection processing on the received signal, and an A/D for converting the output signal of the receiving waveforming and detection circuit 7 into a digital signal. It consists of a converter 8, a color flow information calculation circuit 9 and a Doppler mode calculation circuit 10 connected to the output of the A/D converter 8. The color flow information calculation circuit 9 is a circuit that performs calculation processing for processing color components according to blood flow velocity. The Doppler mode calculation circuit 10 is a circuit for calculating changes in blood flow velocity in a specific region. The outputs of the color flow information calculation circuit 9 and the Doppler mode calculation circuit IO are connected to the display signal generation circuit 11. In addition, the display signal generation circuit 11
A display 12 constituted by a CRT is connected to the output of the .

A schematic configuration of the color flow information calculation circuit 9 is shown in FIG. The MTI filter 21 shown in FIG. 5 is connected to the output of the A/D converter. The MT1 filter 21 is a digital bypass filter, and is used to suppress the power of low-speed components. A frequency calculation circuit 22 is connected to the output of the MTI filter 21. The output of the frequency calculation circuit 22 is a speed for calculating the blood flow velocity, the power of the blood flow signal, and the dispersion.

A power and distribution calculation circuit 23 is connected. Each output of this speed, power, and variance calculation circuit 23 is connected to a power limiter circuit 24 as shown in FIG.

The power limiter circuit 24 includes a power limit value generation circuit 30 and a dispersion limit value generation circuit 31 to which the velocity component of the blood flow signal is input. The power limit value generation circuit 30 is a circuit that generates a predetermined power limit value according to the input speed component. This power limit value generation circuit 30 has a RAM, and a table of each velocity component and its corresponding power limit value is written therein. Further, the dispersion limit value generation circuit 31 is a circuit that generates a predetermined dispersion limit value according to the velocity component of the blood flow signal. This dispersion limit value generation circuit 31 similarly has a RAM, and a table of each speed component and its corresponding dispersion limit value is written in this RAM.

Comparators 32 and 33 are connected to the outputs of the power limit value generation circuit 30 and the dispersion limit value generation circuit 31, respectively. And the power limiter value generation circuit 30
The output of the dispersion limiter value generating circuit 31 is input to the Bz input of the comparator 33. Further, the power component of the blood flow signal is input to the A1 power of the comparator 32, and the dispersion component of the blood flow signal is input to the A2 power of the comparator 33. Comparator 32
The relationship between A+ input and B+ input is A.

When ≦81, rlJ is output, and otherwise, "0" is output. Further, the comparator 33 outputs "1" when the relationship between A2 manpower and 82 manpower is A2≧82, and outputs "0" otherwise.

An OR circuit 34 is connected to the outputs of the comparators 32 and 33. The output of this OR circuit 34 is
A gate 35 is connected to the gate 35, which is switched and controlled according to the output of the gate 35. Further, the power component, velocity component, and dispersion component of the blood flow signal are input to the gate 35. Then, the gate 35 determines that the output of the OR circuit 34 is "1".
It is configured so that it becomes ``open'' only when ``.

Next, the operation will be explained.

First, the high frequency pulse oscillator of the transmitter/receiver circuit 2 is driven,
A high frequency pulse is applied to the probe 1.

As a result, an ultrasonic beam is transmitted from the probe 1 into the living body. The reflected echo reflected within the living body is received by the probe 1 and input to the transmitting/receiving circuit 2.

The reflected echo signal that has undergone predetermined processing in the transmitter/receiver circuit 2 is
The data is input to a tomographic data processing system 3 and a blood flow data processing system 4. The reflected echo signal input to the tomographic data processing system 3 is subjected to signal processing such as amplification, waveform shaping, and filter processing by the receiving wave shaping circuit 5. The data is then converted into digital data by the A/D converter 6 and input to the display signal generation circuit 11. In addition, the reflected echo signal input to the blood flow data processing system 4 is subjected to signal processing such as amplification, waveform shaping, and detection processing by the receiving wave shaping and detection circuit 7.
The A/D converter 8 converts the data into digital data.

This digital data is sent to the color flow information calculation circuit 9.
and is input to the Doppler mode calculation circuit 10.

The low frequency components of the digital data input to the color flow information calculation circuit 9 are removed by the MTI filter 21 (FIG. 5). And frequency calculation circuit 2
2 and a speed, power, and dispersion calculation circuit 23 perform frequency, speed, and power dispersion calculation processing. Each output of this speed and power distribution calculation process 23 is input to a power limiter circuit 24.

In this power limiter circuit 24, the velocity component of the blood flow signal is input to a power limit value generation circuit 30 and a dispersion limiter value generation circuit 31.

The power limit value generation circuit 30 and the dispersion limit value generation circuit 31 refer to the table and generate a power limit value and a dispersion limit value according to the velocity component of the input blood flow signal. The respective outputs of the power limit value generation circuit 30 and the distributed limit value generation circuit 31 are input to the 81 power and B2 power of the comparators 32 and 33, respectively. Further, the power component and dispersion component of the blood flow signal are input to A, input, and A2 manual input of the comparators 32 and 33, respectively.

The comparator 32 outputs "1" when A1≦B+, and "0" otherwise. In the comparator 33, A2
“l” is output when ≧82, and “0” is output otherwise. Each output of the comparators 32 and 33 is connected to an OR circuit 34.
The signal is input to the gate 35 through the . On the other hand, the power component, velocity component, and dispersion component of the blood flow signal are input to the gate 35. The gate 35 allows the power component, velocity component, and dispersion component of the blood flow signal to pass when A≦B1 or A2≧B2. Conversely, the power component A1 of the blood flow signal
is larger than the power limit value B1, and when the dispersion component A2 of the blood flow signal is smaller than the dispersion limit value B2, the gate 35 blocks each component of the blood flow signal.

For example, if the power limit value generation circuit 30 sets the power limit value as shown in curve 40 in FIG. 2, and the dispersion limit value generation circuit 31 sets the dispersion limit value as shown in curve 41 in FIG. do. In this case, when the power p of the blood flow signal belongs to the shaded area (a) in FIG. 2 and the variance σ belongs to the shaded area in FIG. 3, each component of the blood flow signal is blocked by the gate 35. be done.

This makes it possible to reduce noise components resulting from movements of heart valves and walls, and improve the S/N ratio.

The signal passing through the gate 35 is input to the display signal generation circuit 11. Further, the digital signal output of the A/D converter 8 is input to the Doppler mode calculation circuit 1O, and after predetermined calculation processing is performed, it is input to the display signal generation circuit 11. The display signal generation circuit 11 processes the outputs of the A/D converter 6, the color flow information calculation circuit 9, and the Doppler mode calculation circuit 10 into signals that can be displayed on the CRT of the display 12. Information is displayed on the CRT.

(Other Embodiments) In the above embodiments, the power limit I/value generation circuit 20 and the distributed limit 7) value generation circuit 21 both generate each limit value based only on the speed component. , the application of the present invention is not limited thereto. For example, each generation circuit may be operated taking into account not only the velocity component but also the depth of field, sampling frequency, region of interest, etc. Thereby, noise components can be removed more precisely.

(Effects of the Invention) According to the ultrasonic diagnostic apparatus according to the present invention, a power limit value generation circuit and a dispersion limit value generation circuit that generate a limit value according to a velocity component are provided. Noise components resulting from movement can be reduced, thereby improving the S/N ratio.

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram of a power limiter circuit applied to an ultrasonic diagnostic apparatus according to an embodiment of the present invention, FIG. 2 is a diagram showing an example of setting a power limit value, and FIG. 3 is a diagram showing an example of setting a dispersion limit value. FIG. 4 is a schematic block diagram of the apparatus of the embodiment, and FIG. 5 is a schematic block diagram of a color flow information calculation circuit employed in the apparatus of the embodiment. DESCRIPTION OF SYMBOLS 1... Probe, 2... Transmission/reception circuit, 4... Blood flow data processing system, 9... Color flow information calculation circuit, 24
... Power limiter circuit, 30... Power limit value generation circuit, 31... Dispersion limit value generation circuit, 34
...OR circuit, 35...gate. Figure 3 °1

Claims (1)

[Claims] (1) a blood flow data processing section for obtaining in-vivo blood flow data based on ultrasound reflection signals obtained in the living body; and a predetermined blood flow velocity obtained by the blood flow data processing section. a power limit value generation circuit that generates a power limit value of the blood flow; a dispersion limit value generation circuit that generates a predetermined dispersion limit value according to the blood flow velocity obtained by the blood flow data processing section; and an intensity of the blood flow signal. a power limiter circuit that cuts off an output signal from the blood flow data processing section when the dispersion limit value is larger than the power limit value and smaller than the dispersion limit value;