JPH02177949A - Ultrasonic diagnostic device - Google Patents

Abstract

PURPOSE:To obtain the ultrasonic diagnostic picture or blood current spectrum of high resolution by giving prescribed delay quantity to an ultrasonic echo, which is received by the respective oscillators of an ultrasonic probe, by a delay control means, executing the mutual correlation arithmetic of respective output data and controlling the delay quantity in correspondence to an arithmetic result. CONSTITUTION:A delay control circuit 2 is composed of a delay circuit provided corresponding to respective oscillators 1a-1f and a control circuit to control the delay quantity of each delay circuit based on correction data which are determined by a delay correction arithmetic circuit 4. The output of a delay control circuit 2 is connected through an A/D conversion circuit 3 to a mutual correlation arithmetic circuit 4. The mutual correlation arithmetic circuit 4 executes the mutual correlation arithmetic of respective output data from the A/D conversion circuit 3 and outputs the arithmetic result. The arithmetic output of the mutual correlation arithmetic circuit 4 connects to a delay correction arithmetic circuit 5 and the delay correction arithmetic circuit 5 determines the quantity to be delayed, namely, correction quantity of respective ultrasonic echoes (a)-(f) based on the calculated result of the circuit 4. Then, a determined result is outputted as the correction data.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ultrasonic diagnostic apparatus, and particularly to an apparatus capable of correcting a phase shift of ultrasonic echoes received by each transducer.

[Conventional technology]

2. Description of the Related Art In the medical field, ultrasonic diagnostic devices are used to observe tissues, blood flow dynamics, etc. in a living body. This ultrasonic diagnostic device generally consists of a probe that transmits and receives ultrasonic waves, a diagnostic device body to which the probe is connected and has a calculation means, and a CRT that displays diagnostic results. The ultrasonic wave is transmitted from the probe into the living body, the ultrasonic echo reflected from the living body is received by the probe, and this is processed by frequency analysis etc. in the diagnostic device main body. This is used to diagnose blood flow dynamics, etc.

In order to improve the azimuth resolution of such ultrasound diagnostic equipment, it is necessary to narrow down the diameter of the ultrasound beam, that is, to perform focusing, but recently an electronic focus method has been used for this focusing. There is.

[Problem to be solved by the invention]

In the electronic focus, the probe is composed of a plurality of transducers, and each of these transducers is given a delay distribution in the form of a quadratic function, so that the combined wavefront is controlled to be a focused wavefront rather than a plane wave. This narrows down the beam diameter near the focal point. Ultrasonic echoes reflected at this focal point are received by each transducer making up the probe.

At this time, as shown in FIG. 3, since the distances between each of the transducers 10a to foe making up the probe 10 and the focal point F are different, each transducer 10a = 10e receives the signal according to this distance. The phases of the ultrasonic echoes a-e are shifted in a quadratic manner. Therefore, the delay control circuit 2
is applied to each ultrasonic echo a to e so that their phases match.

However, in general, the medium in the biological region is not uniform (the speed of sound differs depending on the medium. Therefore, each vibrator 10
The phases of the ultrasonic echoes a to e received at points a to 10e do not actually have a quadratic distribution as shown in FIG. For this reason, it is not possible to match the phases of the ultrasonic echoes a to e as shown in FIG. 2 by simply applying the quadratic delay amount to each of the ultrasonic echoes a to e using the delay control circuit 20. Can not.

An object of the present invention is to provide a high-resolution ultrasonic diagnostic apparatus that can match the phases of ultrasonic echoes even in a non-like medium.

[Means to solve the problem]

The ultrasonic diagnostic apparatus according to the present invention includes an ultrasonic probe, a delay control means, and a cross-correlation calculation means.

The ultrasonic probe is composed of a plurality of transducers, and emits an ultrasonic beam into the subject and receives ultrasonic echoes reflected within the subject. The delay control means is means for applying a predetermined amount of delay to each ultrasonic echo received by each transducer of the ultrasonic probe. The cross-correlation calculation means performs a cross-correlation calculation on each output data obtained by the delay control means, and based on the calculation result, corrects the phase shift of the ultrasound echo obtained from a predetermined distance within the subject. This means controls the amount of delay of the delay control means so that

[Effect]

In this invention, first, each vibrator of the ultrasonic probe
An ultrasound beam is emitted into the subject, and ultrasound echoes reflected within the subject are received by each transducer of the ultrasound probe.

Next, the delay control means applies a predetermined delay amount determined by the cross-correlation calculation means to each ultrasonic echo received by each transducer of the ultrasound probe.

The cross-correlation calculation means performs a cross-correlation calculation on each output data obtained by the delay control means, and the amount of delay given to the delay control means is determined according to the result of this calculation.

That is, the cross-correlation calculation means determines the amount of phase shift of each ultrasonic echo received by each transducer of the ultrasound probe, and correction data corresponding to this amount of shift is then applied to the delay control means. will be given for each ultrasound echo input to the .

Therefore, it is possible to detect the actual phase shift of the ultrasound echoes received by each transducer, so even if the medium inside the subject is not uniform, the phase shift of each ultrasound echo can be matched. The resolution can be improved.

〔Example〕

FIG. 1 is a block diagram of an ultrasonic diagnostic apparatus according to an embodiment of the present invention. In the figure, reference numeral 1 denotes an ultrasound probe that emits an ultrasound beam into a living body and receives ultrasound echoes reflected within the living body. The ultrasonic probe 1 is composed of a plurality of transducers 1a to 1f. Further, the vibrators 1a to 1f are each connected to a delay control circuit 2. The delay control circuit 2 determines the delay circuits provided corresponding to each of the vibrators 1a to 1f and the amount of delay of each delay circuit based on correction data determined by a delay correction calculation circuit 4, which will be described later. It consists of a control circuit for controlling.

The output of the delay control circuit 2 is sent via the A/D conversion circuit 3 to
It is connected to the cross-correlation calculation circuit 4. The cross-correlation calculation circuit 4 performs a cross-correlation calculation on each output data of the A/D conversion circuit 3 and outputs the calculation result. The calculation output of the cross-correlation calculation circuit 4 is connected to the delay correction calculation circuit 5. The delay correction calculation circuit 5 determines the amount by which each ultrasonic echo azf should be delayed, that is, the correction amount, based on the calculation result of the cross-correlation calculation circuit 4, and outputs the result as correction data.

The cross-correlation calculation circuit 4 and the delay correction calculation circuit 5 constitute a cross-correlation calculation means. Cross-correlation calculation circuit 4
Each correction data outputted from the transducers 1a to 1r is connected to the delay control circuit 2, and is applied to each ultrasonic echo outputted from each of the transducers 1a to 1r.

Further, the output signal of the delay control circuit 2 is input to an external display processing system, and this display processing system allows
Images based on ultrasound echoes are displayed, and ultrasound diagnosis is performed.

Next, the operation will be explained.

First, a high frequency pulse from a transmission system (not shown) is applied to the ultrasound probe l via the delay circuit. As a result, ultrasound beams are emitted from each of the transducers 1a to lf of the ultrasound probe 1 into the living body. This ultrasonic beam is focused in the living body, reflected near the focal point, and each transducer 1
It is input to axlf as an ultrasonic echo. The ultrasonic echoes a to f are then input to the delay control circuit 2.

In this delay control circuit 2, a predetermined amount of delay is given to each of the ultrasound echoes. The output signal of the delay control circuit 2 is A/D converted by the A/D conversion circuit 3 and output as a digital signal.

This digital output signal is input to the cross-correlation calculation circuit 4. The cross-correlation calculation circuit 4 performs a cross-correlation calculation on each input digital signal, and outputs the result of this calculation.

Here, the calculation method of the cross-correlation calculation will be specifically explained.

Now, assume that each signal input to the cross-correlation calculation circuit 4 via the A/D conversion circuit 3 is 80 to gs.

Among these signals, the g0 signal is taken as a reference, and g. Consider the case of finding the phase shift between a signal and another signal. - As an example, let us consider the case of finding the phase shift between the g0 signal and the g signal. The cross-correlation calculation circuit 4 first calculates g at time, signal go(t), and g at time 1τ (τ: parameter).

signal gtct-τ), i.e., I = S
go(t) g t(t-τ) is calculated and output.

Next, the integral value l is calculated in the same manner as described above while shifting τ by an appropriate amount, and the cross-correlation calculation circuit 4 outputs the respective calculation results each time.

Each calculation result of the cross-correlation calculation circuit 4 is sent to the delay correction calculation circuit 5.
is input. The delay correction calculation circuit 5 calculates τ· at which the integral value I is maximum based on the results of each calculation, and outputs it as correction data. This correction data τ. teeth,
The signal is input to a control circuit that controls the delay amount of the ultrasonic echo b (signal gI) of the delay control circuit 2. Delay control circuit 2
is the correction data τ in addition to the preset delay amount for the next input ultrasound echo b. gives a delay of

For the remaining signals 82 to gs, do the same as above,
Correction data τ based on the g0 signal is obtained and provided to the delay control circuit 2 as correction data.

According to this embodiment, the amount of actual phase shift of the ultrasound echo input to each transducer of the ultrasound probe is determined, and the amount of delay is corrected according to this phase shift. Even if the medium is not uniform, the phase of each ultrasonic echo can be completely changed.

[Other Examples]

(a) In the above embodiment, the cross-correlation calculation is performed using the g0 signal as the reference, but it goes without saying that other signals may be used as the reference.

(b) The present invention can also be applied in the vicinity of sample points in the case of blood flow spectrum calculation using the pulsed Doppler method, making it possible to obtain a more accurate blood flow spectrum.

〔Effect of the invention〕

According to the ultrasonic diagnostic apparatus according to the present invention, the delay control means applies a predetermined delay amount to each ultrasonic echo received by each transducer of the ultrasonic probe, and A cross-correlation calculation is performed on each of the output data obtained, and the delay amount of the delay control means is controlled according to the calculation result. The phases of the ultrasound echoes received by each transducer of the child can be matched, and a higher resolution ultrasound diagnostic image and blood flow spectrum 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, and Figs. 2 and 3 illustrate the phase shift of ultrasonic echoes received by each transducer of an ultrasonic probe. This is a diagram for 1... Ultrasonic probe, 2... Delay control circuit, 4...
- Cross-correlation calculation circuit. Patent applicant: Shimadzu Corporation

Claims (1)

[Claims] (1) An ultrasound probe consisting of a plurality of transducers, which emits an ultrasound beam into a subject and receives ultrasound echoes reflected within the subject, and each transducer of the ultrasound probe. a delay control means for giving a predetermined amount of delay to each ultrasonic echo received by the ultrasonic echo; and a cross-correlation calculation of each output data obtained by the delay control means, and based on the result of this calculation, the and cross-correlation calculation means for controlling the delay amount of the delay control means so that a phase shift of ultrasound echoes obtained from a predetermined distance within a specimen is corrected.