Patent EP0202920A2 successfully refreshed from Google Patents.
EP0202920A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Ultrasonic doppler blood flowmeter
Assignee: Panasonic Holdings Corp
•
Filing: 1986-05-20
•
Granted: —
•
Expires: 2006-05-20
Abstract
Abstract Disclosed is an ultrasonic Doppler blood flow-meter intended to measure the velocity of blood flow at an arbitrary position of the body of a subject by making use of Doppler shift of an ultrasonic echo signal. The echo signal including Doppler shift from the blood flow of the body is detected in phase on the basis of standard reference signal, and the distance to an intended position is extracted from the phase detected signal and is integrated, and the direct-current component or ultralow frequency component of the Doppler shift signal obtained from the integrating means is fed back negatively to the integrating means. As a result, the echo signal components of the body tissues are removed, and the frequency of blood flow only can be analyzed, so that an accurate blood flow information may be obtained.
Inventors
- 👤 Yasuhiro Nakamura
- 👤 Masam Kawabuchi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 18:23
CPC Classifications
A; A61; A61B; A61B8/00; A61B8/06
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
223 words
An ultrasonic Doppler blood flowmeter comprising an ultrasonic transmission means to transmit ultrasonic pulses into the body of a subject, an ultrasonic reception means to receive echo signals reflected within the body, a drive circuit to generate ultrasonic pulses to be transmitted by said ultrasonic transmission means, a transmission timing signal circuit to give the timing to generate ultrasonic pulses by this drive circuit, a phase detector to detect the phase of echo signal obtained by said ultrasonic reception means, a reference signal generation circuit L 6 issue a signal serving as the reference for the frequency and phase of transmission signal of said drive circuit and a signal serving as the reference for frequency and phase of reference signal when detecting the phase of said echo signal, a gate signal generating circuit to generate a gate signal at the time corresponding to the echo signal from a desired position, a means to control opening and closing of the phase signal detected by said phase detector by said gate signal, an integrating circuit to obtain by Doppler shift signal by integrating the phase signal passing through said control means and repeating transmission and reception, and a feedback circuit to negatively feed back the direct-current component or ultralow frequency component of the Doppler shift signal obtained in this integrating circuit into the integrating circuit.
Claim 2
Dependent Claim
223 words
An ultrasonic Doppler blood flowmeter comprising an ultrasonic transmission means to transmit ultrasonic pulses into the body of a subject, an ultrasonic reception means to receive echo signals reflected within the body, a drive circuit to generate ultrasonic pulses to be transmitted by said ultrasonic transmission means, a transmission timing signal circuit to give the timing to generate ultrasonic pulses by this drive circuit, a phase detector to detect the phase of echo signal obtained by said ultrasonic reception means, a reference signal generation circuit L 6 issue a signal serving as the reference for the frequency and phase of transmission signal of said drive circuit and a signal serving as the reference for frequency and phase of reference signal when detecting the phase of said echo signal, a gate signal generating circuit to generate a gate signal at the time corresponding to the echo signal from a desired position, a means to control opening and closing of the phase signal detected by said phase detector by said gate signal, an integrating circuit to obtain by Doppler shift signal by integrating the phase signal passing through said control means and repeating transmission and reception, and a feedback circuit to negatively feed back the direct-current component or ultralow frequency component of the Doppler shift signal obtained in this integrating circuit into the integrating circuit.
Claim 3
Dependent Claim
27 words
The ultrasonic Doppler blood flowmeter of Claim 1, wherein the feedback signal from the feedback circuit is fed back to the input terminal of the control means.
Claim 4
Dependent Claim
23 words
The ultrasonic Doppler blood flowmeter of Claim 1, wherein the ultrasonic transmission means and theultrasonic reception means are formed by one ultrasonic probe.
Claim 5
Dependent Claim
26 words
The ultrasonic Doppler blood flowmeter of Claim 1, wherein a sample hold circuit to temporarily hold the integrated result obtained in the integrating circuit is provided.
Claim 6
Dependent Claim
25 words
The ultrasonic Doppler blood flowmeter of Claim l, wherein the feedback signal is taken out from either the integrating circuit or the sample hold circuit.
Claim 7
Dependent Claim
50 words
The ultrasonic Doppler blood flowmeter of Claim 1, wherein a feedback gain control circuit is provided to control the gain of the feedback circuit in proportion to said ultrasonic pulse period, or control in reverse proportion to the time width of the gate signal generated in said gate signal circuit.
Claim 8
Dependent Claim
22 words
The ultrasonic Doppler blood flowmeter of Claim 1, wherein the feedback circuit is composed of a low pass filter by integrating circuit.
Claim 9
Dependent Claim
30 words
The ultrasonic Doppler blood flowmeter of Claim 1, wherein the direct-current feedback circuit is composed of low pass filter by integrating circuit and gain variable amplifier for controlling the gain.
Claim 10
Dependent Claim
36 words
The ultrasonic Doppler blood flowmeter of Claim 1, wherein the direct-current feedback circuit is composed of low pass filter by integrating circuit and time constant control circuit to control the time constant of said integrating circuit.
Claim 11
Dependent Claim
36 words
The ultrasonic Doppler blood flowmeter of Claim 1, wherein the direct-current feedback circuit is composed of low pass filter by integrating circuit and chopper circuit which turns on and off the input of said integrating circuit.
Claim 12
Dependent Claim
16 words
The ultrasonic Doppler blood flowmeter of Claim 1, wherein the control means is an analog switch.
Claim 13
Dependent Claim
69 words
The ultrasonic Doppler blood flowmeter 10 comprising a means to drive an ultrasonic probe in pulses, a means to detect the phase of echo signals from the body of a subject, a means to extract and integrate the phase signal corresponding to a desired position. and a means to negatively feedback the direct-current component or ultralow frequency component of output signal of the integrating means into said integrating means.
Claim 14
Dependent Claim
69 words
The ultrasonic Doppler blood flowmeter 10 comprising a means to drive an ultrasonic probe in pulses, a means to detect the phase of echo signals from the body of a subject, a means to extract and integrate the phase signal corresponding to a desired position. and a means to negatively feedback the direct-current component or ultralow frequency component of output signal of the integrating means into said integrating means.
Claim 15
Dependent Claim
18 words
The ultrasonic Doppler blood flowmeter of claim 12, wherein the gain of the negative feedback means is variable.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.