JPS59105437A - Ultrasonic pulse doppler blood flow meter - 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 a. Technical Field of the Invention The present invention relates to an ultrasonic pulsed Doppler blood flow meter.

b. Prior Art and Problems When measuring the movement of the heart wall using an ultrasound diagnostic device, an image called M mode is viewed.

However, this image simply showed the position of the wall, and it was not possible to directly determine its moving speed.

Further, although it is possible to determine the moving speed of the heart wall using an ultrasonic pulse Doppler blood flow meter, conventional blood flow meters cannot accurately display slow movements.

By the way, when trying to accurately measure slow movements by increasing the frequency of the ultrasound transmitted by an ultrasound pulsed Doppler blood flow meter and increasing the difference between the frequency components of the reflected ultrasound and the reference wave, the transducer It is necessary to replace the user each time. Also, since the attenuation rate of ultrasound is proportional to the frequency,
As the frequency increases, the attenuation rate also increases.

C. Purpose of the Invention Therefore, in the present invention, by increasing the frequency of the reflected ultrasonic wave and the reference wave after reception, the difference between the frequency components of the reflected ultrasonic wave and the reference wave is widened, and even slow movements can be accurately measured. It is something that makes it possible.

d.Structure of the Invention Therefore, the present invention mixes reflected ultrasound received by a transducer and a reference wave, performs frequency analysis on the difference in frequency components between the reflected ultrasound and the reference wave, and calculates blood flow velocity. In the ultrasonic pulse dob 2 blood flow meter that measures a first switch for selecting either the reflected ultrasound received by the transducer or the harmonics created by the first circuit, the reference wave;
The present invention is characterized in that a second switch for selecting the second reference wave is added.

By doing this, the Doppler frequency is conventionally given by C: sound speed fO: reference wave frequency, whereas in the present invention, the reference wave frequency is nf
f'D: new Doppler frequency, frequency increases. . Therefore, it is possible to measure with high precision even objects that move slowly, such as the heart wall, where the difference in frequency components is large. θ Embodiment of the Invention FIG. 1 shows an ultrasonic pulse Doppler blood flow meter which is an embodiment of the invention, and 1 indicates a transducer.

2 is a transmitting amplifier, 3 is a receiving amplifier, 4 is a master oscillator and timing controller, 5 is a nonlinear circuit, 6
1 is an n-th tuned amplifier, '7 is an n-th reference wave generation circuit, 8 is a reference wave generation circuit, 9 is a Doppler detector, 10 is a frequency analyzer, 11 is a display, and 12 to 14 are switches, respectively. In addition, (a) in FIG. 2 shows the input waveform to the nonlinear circuit 5, (
(b) shows the output waveform from the nonlinear circuit 5, (C) shows the output waveform from the n-order tuned amplifier 6, and FIG. 3 shows examples before and after implementing this embodiment. Also, in this example, n-
'Is.

In the master oscillator and timing controller 4, an ultrasonic drive signal of a certain frequency (2 to IOMH2>) is generated.The ultrasonic drive signal amplified by the amplifier 2 is converted into an ultrasonic wave by a transducer. , is transmitted to the subject.The reflected ultrasound that passes through the subject and returns to the transducer is converted into a reflected signal and amplified by an amplifier 3.A circuit 8 includes a master oscillator and a timing controller 4. A reference wave signal is generated in addition to the ultrasonic driving signal generated by the switch 12. When the amplifier 3 is connected to the switch 12, and the circuit 8 is connected to the detector 9 by the switches 13 and 14, a reflected signal is generated. .

The reference wave signal is mixed by a detector 9, and the difference in frequency components between the reflected signal, the reference wave, and the signal is detected.

The master oscillator and timing controller 4 are
An instruction is given to the output detector 9 to send the difference in frequency components from the detector 9 to the analyzer 10 at a timing corresponding to the measurement depth. The difference between the frequency components sent to the analyzer 10 is subjected to frequency analysis and shown to the display device 11.

Next, switch 12 turns on cyanpro, switch 13.1
4 connects the circuit 7 to the detector 9. The reflected wave signal having a waveform as shown in FIG. 2(a) amplified by the amplifier 3 is
2(b) (n times the reflected wave like a house (in this example, n.

3rd harmonic and 5th harmonic with odd number) frequencies.

It is converted into a waveform that includes the seventh harmonic. The amplifier 6 sends only the signal (b) and the third harmonic signal having the waveform shown in FIG. 2(C) to the detector 9.

In the above manner, the frequency of the reflected wave signal is tripled.

Note that if the amplifier 3 is already saturated, the nonlinear circuit 5 is unnecessary. Circuit 7 filters the ultrasonic drive signal generated by the master oscillator and timing core (lower 9), generates a tertiary reference wave signal having a frequency three times the frequency generated by circuit 8, and detects it. Send to vessel 9.

In the detector 9, the third harmonic signal and the third reference wave signal are mixed, and the third harmonic signal and the third reference=1. i
The difference in the frequency component with the number is detected. The master oscillator and timing controller 4 detects the difference in frequency components from the output device 9 to the analyzer 1 at a timing corresponding to the measurement depth.
An instruction is issued to the detector 9 to send the signal to zero. The difference in frequency components sent to the analyzer 10 is frequency analyzed and displayed on the display 11.
will be displayed.

In addition to this, the scale of the display is 3 times that of the direct frequency ridge analysis of the reflected ultrasound, or the frequency is multiplied by 1/3 before displaying.

In this example, when creating the tertiary reference wave, the ultrasonic drive signal generated by the master oscillator and timing controller was filtered to triple the frequency. A master oscillator and a timing controller generate a signal having a frequency of f. By increasing the difference between the frequency components of the reference waves, it is possible to accurately determine the slow movement of the heart wall, etc.

[Brief explanation of drawings]

Claims (1)

[Claims] In an ultrasonic pulsed Doppler blood flow meter that mixes reflected ultrasound received by a transducer with a reference wave, and performs frequency analysis on the difference between the frequency components of the reflected ultrasound and the reference wave to measure blood flow velocity. 1. A first circuit that creates harmonics of the frequency of the reflected ultrasound and extracts only the n-th harmonic; and a second circuit that creates a second reference wave that is n times the frequency of the reference wave. a first switch for selecting either the reflected ultrasound received by the transducer or a harmonic generated by the first circuit; and a first switch for selecting the reference wave or the second reference wave. An ultrasonic pulse Doppler blood flow meter characterized by adding a second switch.