JPS61146238A - Ultrasonic doppler 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] [Field of Application of the Invention] The present invention relates to an ultrasound system that transmits and receives ultrasound pulses to non-invasively observe, for example, the blood flow of a subject or the movement of heart valves using the Doppler effect. This invention relates to a pulsed Doppler device.

[Background of the invention]

Methods for detecting and displaying Doppler signals at multiple points in conventional ultrasonic pulsed Doppler equipment include: 1. A method of frequency analysis and display by moving multiple sample points at regular intervals (several seconds or several heartbeats); There is a method of collecting the phase detection output and using a computer to analyze and display the frequency of multiple points, but the first method is only for analyzing and displaying the channel (CH).
It is difficult to monitor multiple points of concentric time phase. The second method cannot be monitored in real time. There was a drawback.

[Purpose of the invention]

An object of the present invention is to provide an ultrasonic pulse Doppler device that detects depth Doppler signals at multiple points on the same ultrasound beam in real time, and simultaneously analyzes the frequency of the detected signals at multiple points and displays the results on a monitor. There is a particular thing.

[Summary of the invention]

Detection of Doppler signals at multiple points on the same ultrasound beam is realized by providing multiple Doppler signal detection circuits.

Also, for real-time frequency analysis of Doppler signals at multiple points, multiple frequency analysis circuits may be installed, but since the display monitor is the same for single-channel analysis and multi-channel analysis, multi-channel analysis has a higher frequency resolution than single-channel analysis. Since there is no problem even if the frequency is degraded, real-time performance is not impaired even if the frequency analysis of one circuit is performed multiple times.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to FIG.

In response to the launch timing signal output from the control circuit 9, a high voltage pulse is generated from the ultrasonic transmitting circuit 2, which is converted into an ultrasonic wave by the ultrasonic probe 1, and the ultrasonic pulse is transmitted.

Ultrasonic echo signals reflected from internal structures and blood cells are
The ultrasonic probe 1 converts the signal into an electrical signal, and the receiving circuit 3
One is amplified by the detection circuit 6 as a 5B mode image or M mode image video signal, the other is the Doppler shift frequency detected by the Doppler detection circuit 4, and F/v converted by the frequency analysis circuit 5. and the blood flow pattern,
A signal synthesis circuit 7 synthesizes the output of the detection circuit 6 and the output of the frequency analysis circuit 5. The synthesized signal from the signal synthesis circuit 7 is displayed on the display device 8 under the control circuit 9 as a blood flow pattern image together with a B-mode image and an M-mode image. In addition to the launch timing signal from the control circuit 9, the Doppler detection circuit 4 receives a sample hold timing signal.
A reference wave signal is outputted to the display circuit 8, and a sweep control signal is outputted to the display circuit 8.

In the past known examples, the sample and hold timing signal changed at regular intervals to detect and analyze Doppler signals at multiple depths, but according to the present invention, the Doppler signals are processed in parallel as shown in FIG. It is configured to detect. That is,
The amplified reflected signal and the reference wave signal are mixed by the mixing circuit 4-1, and the component of the difference in frequency between the two signals is detected by the low-pass filter 4-2.
-3-1 to 4-3-H detect blood flow signals at a plurality of depths, and each bandpass filter 4-4-1 to 4-4-
Extra high frequency components and low frequency components are removed by n.

The output of the Doppler detection circuit 4 thus obtained is input to the frequency analysis circuit shown in FIG.

The outputs of the n Doppler detection circuits are connected to the changeover switch 5-
1 during one period of ultrasonic repetition, converted into a digital signal by A/D converter 5-2, and stored in memory 5-3.

Next, the frequency is analyzed in the Fourier transform circuit 5-4, and now the analysis for one channel is 256 = 1024.
,! =l) 1024 butterfly operations are required.

On the other hand, since the size of the screen on which the analysis results are displayed is the same for 1 channel and n channel, the size of the screen for displaying analysis results is the same for 1 channel when n channel is used. In other words, 128-point FFT is performed twice for 2 channels, and 6 times for 4 channels.
This means that it is sufficient to execute 4-point FFI' four times. Regarding the number of butterfly calculations at this time, even in the case of two channels, analysis of n channels is completed within the analysis time of one channel, and real-time performance can be maintained.

The FFT results are sequentially outputted to the memory 5-5 for each channel, are combined with a B-mode image or an M-mode image in a signal synthesis circuit 7, and are displayed on a display device 8.

In addition to the methods shown in FIGS. 2 and 3, the method shown in FIG.

As shown in FIG. 5, n bandpass filters 4-4
-1 to 4-4-H output mixing circuit 4-5-1 to 4-5
- n is mixed with the outputs of the local oscillation circuits 4-6-1 to 4-5-n, and the combined signal is used as the output of the mixing circuit 4. This converts the output of the bandpass filter 4-4-n into a.51nWd and a CO3W dnt (Wdn
: Doppler deviation angle frequency), and local oscillation circuit 4-6-
The output of n is b Sin wt, n t+bcO3WL
When nj (, w7,; local oscillation angular frequency), the output of the mixing circuit 4-5-n is as follows.

a 51nWdnt X b 5ill wL, t
-) a C05Wdnt X bcoswL, t
== a bcos (Wdn WLII)
In other words, the nth channel signal has a Doppler deviation frequency above and below the angular frequency WLn. By changing WL for each channel and combining the output signals of each channel, n Signals for channels can be treated as one analysis input signal. Therefore, the fifth
In the figure, the changeover switch 5-1 as shown in FIG. 3 is unnecessary, and the resolution of each channel is the same as that of one channel. In addition, memories 5-3 and 5'-3,
The memories 5-5 and 5'-5 are distinguished by whether they are memories for performing n-channel FFT or memories for performing 1-channel PPT.

〔Effect of the invention〕

According to the present invention, it is possible to obtain blood flow patterns at multiple depths on the same ultrasound beam at the same time. Changes in blood flow velocity distribution during the phase can be captured.

Pressure (intracardiac pressure, blood pressure) It is also possible to obtain the relevant status.

[Brief explanation of drawings]

The figure shows an embodiment of the present invention, and FIG. 1 is a block diagram of an ultrasonic pulse Doppler apparatus. FIG. 2 is a block diagram of an n-channel Doppler signal detection circuit. FIG. 3 is a block diagram of a circuit that inputs the output of FIG. 2 and performs n-channel frequency analysis. FIG. 4 is a block diagram of another embodiment of the n-channel Doppler signal detection circuit. FIG. 5 is a block diagram of a frequency analysis circuit which inputs the output of FIG. 4 and obtains an n-channel blood flow pattern. 1... Ultrasonic probe, 2... Ultrasonic transmitting circuit, 3...
...Reception circuit, 4...Doppler signal detection circuit, 5...
Frequency analysis circuit, 6... Detection circuit, 7... Signal synthesis circuit, 8... Display device, 9... Control circuit, 4-1.
...Mixing circuit, 4-2...Low pass filter, 4-3
'-1~4-3-n...Sample hold circuit, 4-
4-1 to 4-4-n...Band pass filter, 5-1
...OFF HEt switch, 5-2...A/D converter,
5-3...Memory, 5-4...Fourier transform circuit,
5-5...Memory, 4-5-1 to 4-5-n...Mixing circuit, 4-6-1 to 4-6-n...Local oscillation circuit,
5'-3...Memory, 5'-5...Memory.

Claims (1)

[Claims] 1. In an ultrasound pulsed Doppler device consisting of an ultrasound probe, an ultrasound transmission circuit, a reception circuit, a Doppler signal detection circuit, a frequency analysis circuit, and a display device for displaying a frequency analysis image (blood flow pattern), An ultrasonic pulse Doppler device characterized by having a plurality of Doppler signal detection circuits and displaying blood flow patterns at multiple depths simultaneously in real time.