Acquiring accurate measurements for blood flow is a clinically relevant problem of interest. Three-dimensional color flow with partial volume correction (PVC) is a relatively new method for measuring blood flow that accounts for beams located partially outside of the blood vessel. Recent work has shown that the relationship between color flow power and partially perfused voxels is nonlinear. This work investigates the statistics of color power measurements in simulated plug flow to help explain this nonlinear behavior. Data was acquired using Field II simulations in which a 3.75 MHz mechanically swept linear array obtained RF data of blood moving through a vessel. Blood in the vessel exhibited plug flow, and tissue backscatter was set to 40 dB below blood. The statistics of color power at each point in the processing chain were analyzed using histograms, established results in ultrasound statistics, and derived probability density functions (pdfs). For locations completely inside the beam, power before additional processing showed exponential behavior, whereas the square root of power, i.e., amplitude, was Rician distributed. After implementing the Kasai algorithm, the power values could be estimated with a gamma distribution with a shape parameter of 2.21. Kasai powers corresponding to tissue could also be fitted with a gamma distribution, albeit with a shape parameter close to 1, indicating close to exponential behavior. Kasai powers for partial volume data were intermediate between the tissue and blood data. A method for estimating partial volume weight from the skewness and kurtosis of samples taken from the same location is also discussed.

Date: Monday, June 28, 2021
Time: 10:00 AM
Zoom: https://umich.zoom.us/j/97162930417
Chair: Dr. Oliver Kripfgans