US4848354A — Method and apparatus for investigating a circulat…

Claim 1

Independent Claim 250 words

Method for generating a multidimensional map of blood velocities in the circulatory system of living species, using the Doppler effect of backscattered ultrasound, the flow map being shown in real time on a display device, with the ability to select small sample volumes in the map where an approximate spectral analysis of the Doppler signal can be shown on a display as a function of time together with the moving flow map in real time to illustrate the time variation of the blood velocities in the sample volumes selected, comprising the steps of: (a) transmitting a pulse type ultrasonic beam which is swept in two or more dimensions through a region of the biological structure which is to be investigated; (b) sampling the backscattered ultrasonic signal in a plurality of sample volumes along each beam direction of the transmitted ultrasonic pulses; (c) determining a velocity parameter of the blood flow for each sample volume and beam direction by means of the Doppler principle; (d) assigning a coded presentation on a display screen, displaying said velocity parameters for each sample volume and beam direction as a flow map; synthesizing continuous substrate signals from segments of said backscattered signal from selected sample volumes to produce a continuous representation of the signal from these sample volumes; (e) audibly presenting and frequency analyzing said continuous representation to estimate the variation of the blood velocities in said selected sample volumes as a function of time; and (f) displaying said frequency analyzed signal on a display.

Claim 2

Dependent Claim 250 words

Method for generating a multidimensional map of blood velocities in the circulatory system of living species, using the Doppler effect of backscattered ultrasound, the flow map being shown in real time on a display device, with the ability to select small sample volumes in the map where an approximate spectral analysis of the Doppler signal can be shown on a display as a function of time together with the moving flow map in real time to illustrate the time variation of the blood velocities in the sample volumes selected, comprising the steps of: (a) transmitting a pulse type ultrasonic beam which is swept in two or more dimensions through a region of the biological structure which is to be investigated; (b) sampling the backscattered ultrasonic signal in a plurality of sample volumes along each beam direction of the transmitted ultrasonic pulses; (c) determining a velocity parameter of the blood flow for each sample volume and beam direction by means of the Doppler principle; (d) assigning a coded presentation on a display screen, displaying said velocity parameters for each sample volume and beam direction as a flow map; synthesizing continuous substrate signals from segments of said backscattered signal from selected sample volumes to produce a continuous representation of the signal from these sample volumes; (e) audibly presenting and frequency analyzing said continuous representation to estimate the variation of the blood velocities in said selected sample volumes as a function of time; and (f) displaying said frequency analyzed signal on a display.

Claim 3

Dependent Claim 43 words

Method according to claim 1, wherein the step of determining, for each sample volume and beam direction the velocity parameter of the blood flow by means of the Doppler principle, comprises determining the maximum velocity of the blood flow in each sample volume.

Claim 4

Dependent Claim 43 words

Method according to claim 1, wherein the step of determining, for each sample volume and beam direction the velocity parameter of the blood flow by means of the Doppler principle, comprises determining the average velocity of the blood flow in each sample volume.

Claim 5

Dependent Claim 39 words

Method according to claim 1, wherein the step of determining, for each sample volume and beam direction the velocity parameter of the blood flow by means of the Doppler principle, comprises determining the spectral width of the blood flow.

Claim 6

Dependent Claim 52 words

Method according to claim 1 wherein the step of determining, for each sample volume and beam direction the velocity parameter of the blood flow by means of the Doppler principle, comprises employing a combination of average velocity of the blood flow and range of the blood velocity distribution within each sample volume.

Claim 7

Dependent Claim 18 words

Method according to claim 1, wherein the ultrasonic beam is swept continuously over the region to be investigated.

Claim 8

Dependent Claim 22 words

Method according to claim 1, wherein the coded presentation of the velocity parameters takes place in the form of a gray scale.

Claim 9

Dependent Claim 22 words

Method according to claim 1, wherein the coded presentation of the velocity parameters takes place in the form of a color scale.

Claim 10

Dependent Claim 21 words

Method according to claim 1, wherein the velocity parameter is determined on the basis of a spectral analysis of the signal.

Claim 11

Dependent Claim 53 words

The method of claim 1 further comprising the steps of (g) combining the imaging of the velocity parameters with an echo amplitude imaging of the biological structure by time-sharing between Doppler measurements and amplitude imaging, whereby information from the echo imaging is displayed on the screen in combination with the velocity parameter images.

Claim 12

Dependent Claim 279 words

Apparatus for performing a method for generating a multidimensional map of blood velocities in the circulatory system of living species, using the Doppler effect of backscattered ultrasound, the flow map being shown in real time on a display device, with the ability to select small sample volumes in the map where an approximate spectral analysis of the Doppler signal can be shown on a display as a function of time together with the moving flow map in real time to illustrate the time variation of the blood velocities in the sample volumes selected comprising: (a) ultrasonic transmitting means including a transducer for transmitting an ultrasonic signal; (b) ultrasonic receiver means for receiving said backscattered ultrasound; (c) Doppler processor means coupled to said receiver means for sampling the backscattered signal at a number of sample volumes along a number of beam directions for determining a velocity parameter; (d) a diplay means; (e) a control means coupled to said Doppler processor means for controlling the Doppler processor means and to the display means so that the velocity parameters from the whole region investigated are displayed in a coded form; (f) selecting means for selecting sample volumes in said flow map for display as a function of time; (g) synthesizer means for generating substitute signals to provide a continuous representation of the Doppler signal from the selected sample volumes; (h) an analyzer means for frequency analyzing said substitute signals and having an output signal which represents an estimate of the variation of the blood velocities in the selected sample volumes as a function of time; (i) means for displaying said analyzed signal on one of said display means and another display device.

Claim 13

Dependent Claim 279 words

Apparatus for performing a method for generating a multidimensional map of blood velocities in the circulatory system of living species, using the Doppler effect of backscattered ultrasound, the flow map being shown in real time on a display device, with the ability to select small sample volumes in the map where an approximate spectral analysis of the Doppler signal can be shown on a display as a function of time together with the moving flow map in real time to illustrate the time variation of the blood velocities in the sample volumes selected comprising: (a) ultrasonic transmitting means including a transducer for transmitting an ultrasonic signal; (b) ultrasonic receiver means for receiving said backscattered ultrasound; (c) Doppler processor means coupled to said receiver means for sampling the backscattered signal at a number of sample volumes along a number of beam directions for determining a velocity parameter; (d) a diplay means; (e) a control means coupled to said Doppler processor means for controlling the Doppler processor means and to the display means so that the velocity parameters from the whole region investigated are displayed in a coded form; (f) selecting means for selecting sample volumes in said flow map for display as a function of time; (g) synthesizer means for generating substitute signals to provide a continuous representation of the Doppler signal from the selected sample volumes; (h) an analyzer means for frequency analyzing said substitute signals and having an output signal which represents an estimate of the variation of the blood velocities in the selected sample volumes as a function of time; (i) means for displaying said analyzed signal on one of said display means and another display device.

Claim 14

Dependent Claim 66 words

Apparatus according to claim 11, further comprising an echo amplitude processor having circuitry for pulse echo amplitude imaging of the biological structure, said echo processor being controlled by a control signal from said control means for operating in a time-sharing mode with said Doppler processor means to display echo amplitude image information on said display means in combination with the flow map of the velocity parameters.

Claim 15

Dependent Claim 135 words

Apparatus according to claim 11 in which the Doppler processor means comprises a high-pass filter for removing backscattered signal components due to tissue structure further including a capacitor bank having a plurality of capacitors; means for electronically switching said capacitors to form a series capacitor of the high-pass filter, each of said plurality of capacitors in the capacitor bank being separately addressable by said switching means for connecting a selected capacitor for each depth point, means for scanning the output of the high-pass filter with a small time delay (τ) with respect to the connection of a capacitor, said frequency analyzer provided after the high-pass filter for determining a frequency spectrum of the backscattered signal in each depth point; and, means for calculating a frequency parameter from said output signal of said frequency analyzer means.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1992-07-17	1993-01-16	1993-07-18	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1996-07-17	1997-01-16	1997-07-18	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2000-07-17	2001-01-16	2001-07-18	$7700.00	Window Closed / Lapsed

Method and apparatus for investigating a circulatory system in living biological structures

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