JPS63192425A - Ultrasonic doppler blood flow speed measuring apparatus - Google Patents

Abstract

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

Description

[Detailed Description of the Invention] [Summary] In order to improve the accuracy of Doppler measurement in an ultrasonic Doppler blood flow rate measuring device, an ultrasonic transducer is equipped with a fundamental vibration mode (low frequency) transmitting/receiving circuit and a harmonic wave Connect the vibration mode (high frequency) transmitter/receiver circuit via a switching circuit, and when measuring low blood flow velocity at short distances, connect the above high frequency transmitter/receiver circuit to measure high blood flow velocity at other long distances or short distances. In some cases, a control section is provided to perform switching control to connect the low frequency transmitting/receiving circuit.

[Industrial application field]

The present invention relates to an ultrasonic Doppler blood flow velocity measuring device, and in particular,
This paper relates to a circuit configuration method for measuring blood flow velocity with high precision using Doppler measurement.

With recent advances in medical diagnostic technology, there has been a demand for highly accurate Doppler measurement in the field of Doppler measurement using ultrasound signals.

Generally, when using an ultrasound signal for Doppler measurement, there are advantages and disadvantages as shown in Table 1 depending on the frequency used.

That is, in terms of resolution, Doppler measurement using high-frequency ultrasound signals is advantageous because the sample volume increases when low-frequency ultrasound signals are used. Regarding the next depth of reach, that is, the depth of diagnosis, low-frequency ultrasound signals are advantageous due to the problem of absorption by living bodies. and,
Low-frequency ultrasound signals are advantageous in detecting the maximum blood flow velocity during Doppler measurement.

Table 1 Therefore, a Doppler measurement method that is suitable for its advantages and disadvantages is required.

[Prior art and problems to be solved by the invention] FIG. 3 is a diagram illustrating a conventional Doppler measurement method.

As shown in this figure, in the conventional method, an ultrasonic signal of a specific frequency is connected to an ultrasonic transducer 1 via a narrowband transmitting/receiving circuit 10, and from a specific sample point of a specific ultrasound beam. The Doppler signal was analyzed by a known signal processing circuit (FFT analyzer) 11, and the Doppler blood flow velocity at the sample point was measured.

Therefore, if Doppler measurement is performed by transmitting and receiving high-frequency ultrasound signals to and from the ultrasound transducer 1, high blood flow velocity measurement accuracy cannot be obtained; If Doppler measurement is performed by transmitting and receiving low-frequency ultrasound signals to User 1, the resolution will be low (and the sample volume will be large, resulting in a There was a problem in that the transmitting/receiving circuit and the ultrasonic transducer had to be replaced.

In view of the above-mentioned conventional drawbacks, the present invention provides an ultrasonic transducer that has a fundamental vibration mode and a harmonic vibration mode. It is an object of the present invention to provide a Doppler blood flow velocity measurement device that performs Doppler measurement that is compatible with the advantages and disadvantages of Doppler measurement using ultrasound signals and the ultrasound frequency, focusing on the ability to transmit and receive signals.

[Means for solving problems]

FIG. 1 is a diagram showing an example of the configuration of an ultrasonic Doppler blood velocity measuring device according to the present invention.

In the present invention, a fundamental vibration mode transmitting/receiving circuit 2 and a harmonic vibration mode transmitting/receiving circuit 3 are connected to the ultrasonic transducer 1 via a switching circuit 4, and when measuring low blood flow velocity at a short distance,
The control unit 5 performs switching control so that the harmonic vibration mode transmitting/receiving circuit 3 is connected, and the fundamental vibration mode transmitting/receiving circuit 2 is connected when measuring other long-distance or short-distance high-speed blood velocity measurements. Configure to prepare.

[Effect]

That is, according to the present invention, in order to improve the accuracy of Doppler measurement in an ultrasonic Doppler blood flow velocity measurement device, the ultrasonic transducer is equipped with a fundamental vibration mode (low frequency) transmission/reception circuit and a harmonic vibration mode. (High frequency) Transmitting/receiving circuit is connected via a switching circuit, and when measuring low blood flow velocity at a short distance, the above high frequency transmitting/receiving circuit is connected, and when measuring high blood flow velocity at other long distances or short distances, the above Since it includes a switching control section that connects the low-frequency transmitting and receiving circuit, it has the effect of improving the accuracy of Doppler measurement using ultrasonic signals.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

The above-mentioned FIG. 1 is a diagram showing an example of the configuration of the ultrasonic Doppler blood velocity measuring device of the present invention, and FIG. 2 is a diagram showing the switching logic of the transmitting/receiving circuit according to the present invention. , a fundamental vibration mode (low frequency; f,) transmitting and receiving circuit 2, a harmonic vibration mode (high frequency: f,...) transmitting and receiving circuit 3, and a switching circuit 4 thereof.

The control unit 5 is a necessary means for implementing the present invention. It should be noted that the same reference numerals refer to the same objects throughout the design.

Hereinafter, a method of configuring the ultrasonic Doppler blood velocity measuring device of the present invention will be explained with reference to FIGS. 1 and 2.

As mentioned above, an ultrasonic transducer can transmit and receive ultrasonic signals in a fundamental vibration mode and a harmonic vibration mode. Therefore, using the fundamental mode and the third harmonic mode, for example, 2 MHz.

6 MHz ultrasound signals can be transmitted and received to the living body via the same ultrasound transducer.

Furthermore, as shown in Table 1 above, Doppler measurement using low-frequency ultrasound signals is generally advantageous in detecting blood flow velocity using Doppler measurement, but when the blood flow velocity of the object to be measured is low. Focusing on the fact that even high-frequency ultrasonic signals can be measured, the present invention sets the switching logic of the transmitter/receiver circuit shown in FIG. 2. Here, fL indicates that a low frequency transmitting/receiving circuit is applicable, and fH indicates that a high frequency transmitting/receiving circuit is applicable.

In this figure, in cases ■ and ■, as seen from Table 1 above, the diagnosis depth (reaching depth) is deep, so the low frequency (
It is necessary to use an ultrasonic signal of rL), and in Doppler measurement, as mentioned above, low frequencies are good, so the frequency of the ultrasonic signal used is fL as shown in this figure.
shall be.

Next, in case (■), since the diagnostic depth is shallow, it is desirable to use a high frequency (fH) ultrasound signal from the viewpoint of resolution, and since the blood flow velocity detected by Doppler measurement is slow, the same high frequency Since it is possible to use ultrasonic signals of
In this case, it is set as f, with emphasis on resolution.

In the last case (■), since the blood flow velocity measured by Doppler measurement is fast, it is necessary to use a low-frequency ultrasound signal from the viewpoint of Doppler measurement accuracy, and the depth of diagnosis is shallow. Since there is no absolute condition to use particularly high-frequency ultrasound signals, fL is focused on Doppler measurement.
shall be.

When an ultra-beak Doppler blood velocity measuring device is configured based on the above conditions, it becomes as shown in FIG. 1.

That is, a transmitter/receiver circuit 2 for low frequency (rt, ) and a transmitter/receiver circuit 2 for high frequency (r
The transmitter/receiver circuit 3 of H) is configured to be able to drive the ultrasonic transducer 1 by being switched by a switching circuit 4, and the control unit 5 generates a switching signal S based on the logic conditions shown in FIG. 2 above to perform the switching. By controlling the circuit 4, highly accurate Doppler measurement can be performed.

As described above, the present invention has the following advantages: the ultrasonic transducer can be used in the fundamental vibration mode and the harmonic vibration mode, and in Doppler measurement, it is necessary to use a low-velocity ultrasonic signal, and the resolution , focused on the fact that the optimal frequency of the ultrasound signal differs depending on the diagnostic depth, and prepared a transmitter/receiver circuit for the fundamental vibration mode (low frequency) and a transmitter/receiver circuit for the harmonic vibration mode (high frequency) to perform Doppler measurement. The feature is that the two types of transmitter/receiver circuits are switched depending on the depth and the blood flow velocity of the measurement target to perform highly accurate Doppler measurement.

〔Effect of the invention〕

As explained above in detail, the ultrasonic Doppler blood flow velocity measuring device of the present invention has basic features in the ultrasonic transducer in order to improve the accuracy of Doppler measurement in the ultrasonic Doppler blood velocity measuring device. Vibration mode (low frequency) transmitting and receiving circuit,
Connect the harmonic vibration mode (high frequency) transmitter/receiver circuit via a switching circuit, and when measuring low blood flow speed at a short distance, connect the above high frequency transmitter/receiver circuit to measure high blood flow speed at other long distances or short distances. At the time of measurement, since the control unit is provided to perform switching control to connect the low frequency transmitting/receiving circuit, it is possible to improve the accuracy of Doppler measurement using ultrasonic signals.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of the configuration of the ultrasonic Doppler blood velocity measuring device of the present invention. FIG. 2 is a diagram showing the switching logic of the transmitter/receiver circuit according to the present invention. FIG. 3 is a diagram explaining the conventional Doppler measurement method. It is. In the drawing, l is an ultrasonic transducer. 2 is a low frequency (h) transmitting and receiving circuit. 3 is a high frequency (RW) transmitting/receiving circuit. 4 is a switching circuit, and 5 is a control section. 10 is a narrowband transmitting/receiving circuit. 11 is a signal processing circuit (FFT analyzer). are shown respectively. 1st scream 4! 1J=tsL9? :4 river gt> t77! J#,
t*JtE, ftj; [Kaya 2 flash

Claims (1)

[Claims] An ultrasonic transducer (1) is connected to a fundamental vibration mode transmitting/receiving circuit (2) and a harmonic vibration mode transmitting/receiving circuit (3) via a switching circuit (4). When measuring low blood flow velocity, the harmonic vibration mode transmitter/receiver circuit (3
), and during other long-distance or short-distance high-speed blood flow velocity measurements, the control unit (5) performs switching control to connect the basic vibration mode transmitting/receiving circuit (2). Features: Ultrasonic Doppler blood flow velocity measuring device.