JPH0685776B2 - Automatic setting device for blood flow velocity measurement position - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention repeatedly irradiates a blood vessel to be measured with an ultrasonic pulse signal, receives a reflected echo, and receives a Doppler signal included in the echo. The present invention relates to an apparatus for measuring the blood flow velocity of a blood vessel to be measured based on the above, and relates to an automatic setting apparatus for a blood flow velocity measurement position used for setting a measurement position in a blood vessel to be measured.

(B) Conventional Technology Conventionally, the position of a blood vessel to be measured is set while observing a tomographic image of that portion. However, when the ultrasonic pulse is applied to the inside of the body for measuring the blood flow velocity, a tomographic image cannot be seen for the reason of the measurement. Therefore, if the measurement position is displaced during measurement, the measurement may be interrupted, and the measurement position may be reset while viewing the tomographic image again.

On the other hand, in the case of using a single-probe pulsed Doppler device without a tomographic device, it is difficult to do this because a high degree of skill is required to find the blood vessel to be measured.

(C) Purpose The present invention has an object to provide an automatic setting device for a blood flow velocity measurement position, which allows easy setting of the blood flow velocity measurement position and automatically corrects the deviation of the measurement position.

(D) Configuration The blood flow velocity measuring position automatic setting device of the present invention repeatedly irradiates a blood vessel to be measured with an ultrasonic pulse signal, successively receives reflected echoes, and receives a Doppler signal contained in the echoes. When sequentially measuring the blood flow velocity of the measured blood vessel based on, in the device used to set the measurement position in the measured blood vessel, the next ultrasonic pulse signal after the ultrasonic pulse signal is irradiated. Sampling means for sampling the echo received before the irradiation of the laser beam, detecting means for sequentially detecting the Doppler signal contained in the sampled echo, and the sampling means based on the detection result of the detecting means. And a sampling control means for controlling the sampling timing of, when the detection means stops detecting the Doppler signal. Is a gate signal of a predetermined pulse width that enables sampling by the sampling means between the trigger signal for generating an ultrasonic wave and the next trigger signal from t1 to tn.
When the Doppler signal is detected by the detection unit, the gate signal is applied to the sampling unit at a time delay t when the Doppler signal is sampled.

The principle of the present invention will be described with reference to FIG.

Ultrasonic probe 1 installed at a predetermined position on the body surface S
The ultrasonic pulse signal is applied to the measured blood vessel 2. Thereafter, the echo is sampled at preset time delays of t1 to tn (n is an arbitrary integer). Then, it is detected whether the sampled echo contains a predetermined Doppler signal. If the Doppler signal is included, then the echo is sampled at the time delay t. In this way, the measured position 3 is automatically set in the measured blood vessel 2.

(E) Embodiment FIG. 2 is a block diagram schematically showing the construction of one embodiment of the automatic apparatus for setting the blood flow velocity measuring position according to the present invention. In addition,
FIG. 2 also shows the components of the blood flow velocity measuring device.

In the figure, 1 is an ultrasonic probe including an ultrasonic transducer of 2.5 MHz, for example. A wave transmission circuit 2 drives the ultrasonic probe 1. A wave receiving circuit 3 amplifies the echo input to the ultrasonic probe 1. 4 is 2.
It is an oscillator that generates a reference wave that is a 5 MHz sine wave. 5
Is a phase shifter for shifting the reference wave by 90 degrees. Reference numerals 6a and 6b denote multipliers that multiply the output signal of the wave receiving circuit 3 by a reference wave or a reference wave that is phase-shifted by 90 degrees. 7a and 7b are multipliers 6
It is a low-pass filter that is given each output of a and 6b. The components described above are included in the blood flow velocity measuring device. Next, a component as an automatic setting device of the blood flow velocity measurement position will be described.
8A and 8b are sampling circuits, which are low pass filters
The signal passed through 7a and 7b is sampled. Reference numeral 9 denotes a wave transmission timing circuit, which inputs a reference wave to give a trigger for generating an ultrasonic pulse signal to the wave transmission circuit 2 at regular intervals. Reference numeral 10 is a sample hold timing circuit that controls the opening and closing of the gates included in the sampling circuits 8a and 8b. The circuit 10 is, for example, by a counter,
After the ultrasonic pulse is emitted, the time delay for opening the gate is arbitrarily set. Reference numeral 11 denotes a Doppler signal detection circuit including a detection circuit and the like, which detects the Doppler signal included in the output signal of the sample hold circuit 8b. The sampling circuits 8a and 8b correspond to sampling means, the Doppler signal detection circuit 11 corresponds to detection means, and the sample hold timing circuit 10 corresponds to sampling control means.

Next, the operation of the embodiment having the above configuration will be described.

FIG. 3 is an operation waveform diagram of each part of the embodiment shown in FIG.

From the wave transmission timing circuit 9, a trigger as shown in FIG. As a result, the ultrasonic probe 1 emits an ultrasonic pulse S1 as shown in FIG. Then, the echo S2 frequency-modulated by the Doppler signal is input to the receiving circuit 3 after a certain time has elapsed since the ultrasonic pulse S1 was emitted.

The output signal of the wave receiving circuit 3 is given to the multipliers 6A and 6b.
The multiplier 6a multiplies this by a reference wave, and the multiplier 6b multiplies the 90-degree phase shift reference wave, respectively, and outputs the output signal to the low-pass filter 7a and
Give to 7b. The signals that have passed through the low pass filters 7a and 7b are input to the sample hold circuits 8a and 8b.

On the other hand, the sample and hold circuits 8a and 8b are provided with the gate control signal from the sample and hold timing circuit 10 as shown in FIGS. The gate control signals are t1 to tn (n
Is an arbitrary integer). Therefore, the sample and hold circuits 8a and 8b sample the input signal every time t1 to tn after the ultrasonic pulse S1 is emitted.

Then, a part of the output of the sample hold circuit 8b is given to the Doppler signal detection circuit 11. Doppler signal detection circuit 11
Detects a Doppler signal from an output sampled when a gate signal with a time delay t is issued, as shown in FIG. The circuit 11 which has detected the Doppler signal gives a predetermined detection signal to the sample hold timing circuit 10. After that, while the Doppler signal detection circuit 11 is detecting the Doppler signal, the sample hold timing circuit 10 issues a gate control signal with the time delay t.

Then, if the measurement position is displaced for some reason during the measurement, the Doppler signal detection circuit 11 does not detect the Doppler signal. As a result, the sample hold timing circuit 10 issues the gate signal with the time delay of t1 to tn, and automatically sets the time delay of the gate control signal for detecting the Doppler signal.

In this way, the measurement position is automatically set on the blood vessel whose blood flow velocity is to be measured.

The outputs of the sample and hold circuits 8a and 8b are given to, for example, a fast Fourier transformer (FFT) (not shown) connected to the next stage of this device. As a result, the position of the measured blood vessel, the blood flow velocity, etc. are measured.

The time delays t1 to tn preset in the sample hold timing circuit 10 are arbitrarily set according to a certain range of the blood vessel to be measured. For example, the operator can set a so-called window with a time delay according to the region where the blood vessel to be measured is considered to exist. As a result of opening the gates of the sample hold circuits 8a and 8b in this range, the measurement position is automatically set to the position where the Doppler signal is detected. Thereby, even if there are a plurality of blood vessels in the ultrasonic pulse irradiation direction, only the Doppler signal of the blood vessel to be measured can be obtained.

Further, in the above-described embodiment, a part of the output of the sample hold circuit 8b is given to the Doppler signal detection circuit 11, but it goes without saying that it may be a part of the output of the circuit 8a. .

(F) Effect The blood flow velocity measurement position automatic setting device according to the present invention determines the time delay for opening the gate of the sample hold circuit based on the detection of the Doppler signal from the echo, so that the measurement position can be set easily. Can be done.

Further, even if the measurement position is shifted, the time delay for automatically detecting the Doppler signal is selected, so that the measurement position is automatically corrected. Therefore, unlike the conventional device, it is not necessary to stop the measurement and manually set the measurement position again, which is convenient for practical use.

[Brief description of drawings]

FIG. 1 is a diagram for explaining the principle of the present invention, FIG. 2 is a block diagram schematically showing the configuration of an embodiment of an automatic setting device for the blood flow velocity measuring position according to the present invention, and FIG. FIG. 3 is an operation waveform diagram of each part of the embodiment shown in FIG. 2. 1 ... Ultrasonic probe, 2 ... Wave sending circuit, 3 ... Wave receiving circuit, 4 ... Oscillator, 5 ... Phase shifter, 6a, 6b ... Multiplier,
7a, 7b ... Low-pass filter, 8a, 8b ... Sample-hold circuit, 9 ... Transmission timing circuit, 10 ... Sample-hold timing circuit, 11 ... Doppler signal detection circuit.

Claims (1)

[Claims] 1. A blood vessel to be measured is repeatedly irradiated with an ultrasonic pulse signal, echoes that are reflected are sequentially received, and the blood flow velocity of the blood vessel to be measured is sequentially obtained based on a Doppler signal included in the echo. At the time of measurement, in the device used to set the measurement position to the blood vessel to be measured, in the echo received between the irradiation of the ultrasonic pulse signal and the next ultrasonic pulse signal Sampling means for sampling against, a detection means for sequentially detecting the Doppler signal contained in the sampled echo,
Sampling control means for controlling the sampling timing of the sampling means based on the detection result of the detection means, the sampling control means for generating ultrasonic waves when the detection means stops detecting Doppler signals Between the trigger signal and the next trigger signal, the gate signal having a predetermined pulse width that enables sampling by the sampling means is sequentially given to the sampling means with a time delay of t1 to tn, and when the detection means detects the Doppler signal. An automatic setting device for a blood flow velocity measurement position, wherein a gate signal is given to the sampling means at a time delay t when the Doppler signal is sampled.