Dissertation Defense Announcement

Herff College of Engineering announces the Final Dissertation Defense

Omar Yunis

for the Degree of Doctor of Philosophy

March 24, 2022 at 03:15 PM on Zoom

Advisor: Dr. Carl Herickhoff

Development and Characterization of a Lateral Localization Post-processing Algorithm Using Multiple Receive Apodizations

ABSTRACT: "Ultrasound localization microscopy (ULM) is a super-resolution vascular imaging technique that tracks the position of individual circulating microbubbles. Conventional ULM methods fit a normal distribution to a coarsely-pixelated brightness image of a microbubble, and assume the microbubble's position is the mean. In this work, we developed alternative algorithms to precisely and accurately estimate the location of a microbubble by considering multiple even and odd receive apodization profiles. These receive apodization profiles each yield a point spread function with a unique lateral character, enabling intra-beam determination of a scatterer's location. Algorithms were refined and evaluated for the case of focused-beam transmits over a range of F-numbers, and for the case of ultrafast, multi-angle plane-wave compounding. The performance of the algorithms was experimentally evaluated on a research ultrasound scanner using a P4-2v phased array probe and a custom wire-target phantom. Results show that the position of the scatterer was resolvable to less than one-fourth of the diffraction limited resolution."