Flow imaging detector
AssigneeHewlett-Packard Company
InventorsSteven C. Leavitt, David Lipschutz, Stephen E. Lincoln, Karl Thiele, Paul A. Magnin
Life of this patent
Estimating the term…
Abstract
Estimates of the average velocity and turbulence of blood flow are determined by weighting the instantaneous frequencies of a returning Doppler signal. The weighting can be chosen so that the estimates are optimized. The weighting can be chosen so as to duplicate the algorithm of other ultrasound flow imaging systems.
Claims9
In apparatus for deriving signals representing the velocity and signals representing the turbulence of fluid flow at different ranges along a line in response to quadrature components of reflections from said ranges of a plurality of bursts of ultrasonic carrier waves transmitted along the line wherein the quadrature components are displaced from each other by 90.degree. of the carrier wave, the combination of
- input circuits to which said quadrature components are to be respectively applied,
- means coupled to said input circuits for deriving first signals respectively indicating the angles represented by the quadrature components,
- means coupled to said latter means for deriving second signals respectively representing the differences between the angles indicated by said first signals for successive bursts at each range,
- means for deriving at least one weighting factor for each of said second signals,
- means for deriving third signals respectively representing the average velocity of fluid flow at each range from the second signals for the range and corresponding weighting factors, and
- means for deriving fourth signals respectively representing the turbulence of fluid flow at each range from the second signals for the range and corresponding weighting factors.
In apparatus for deriving signals representing the velocity of fluid flow at different ranges along a line in response to quadrature components of reflections from said ranges of a plurality of bursts of ultrasonic carrier waves transmitted along the line wherein the quadrature components are displaced from each other by 90.degree. of the carrier wave, an improvement comprising
- input circuits to which said quadrature components are to be respectively applied,
- means coupled to said input circuits for deriving first signals respectively representing the angles represented by the quadrature componenets,
- means coupled to said latter means for deriving second signals respectively representing the differences between the angles represented by said first signals for successive bursts at each range,
- means for deriving respective weighting factors for said second signals that is a function of at least one of:
- the time following TGC, the vector amplitudes of said second signals and said second signals,
- means for deriving the products of said weighting factors and their respective second signals for each range, and
- means for deriving fourth signals respectively representative of the velocity of flow at each range that is the average of said products.
In apparatus for deriving signals representing the turbulence of fluid flow at different ranges along a line in response to quadrature components of reflections from said ranges of a plurality of bursts of ultrasonic carrier waves transmitted along the line wherein the quadrature components are displaced from each other by 90.degree. of the carrier wave, an improvement comprising
- input circuits to which said quadrature components are to be respectively applied,
- means coupled to said input circuits for deriving first signals respectively representing the angles represented by the quadrature components,
- means coupled to said latter means for deriving second signals respectively representing the differences between the angles represented by said first signals for successive bursts at each range,
- means for deriving respective weighting factors for said second signals that is a function of at least one of:
- the TGC, the vector amplitudes of said second signals,
- means for deriving the products of said weighting factors and their respective second signals for each range, and
- means for deriving a signal indicative of turbulence from said weighting factors and their corresponding second signals.
In apparatus for deriving indications of the velocity and turbulence of fluid flow at different ranges along a line in response to quadrature components of reflections from said ranges of a plurality of bursts of ultrasonic carrier waves transmitted along the line wherein the quadrature components are displaced from each other by 90.degree. of the carrier wave, an improvement comprising
- input circuits to which said quadrature components are to be respectively applied,
- means coupled to said input circuits for deriving first signals respectively representing the angles represented by the quadrature components,
- means coupled to said latter means for deriving second signals respectively representing the differences between the angles represented by said first signals for successive bursts at each range,
- means for deriving at least one weighting factor for each of said second signals,
- means for deriving the products of said weighting factors and their respective second signals,
- means for deriving a signal representative of the velocity of flow at a range that is an average of said products for each range, and
- means for deriving a signal representative of the turbulence of flow at a range from said products.
Dependencies are inferred from the claim text.