Electronic Theses and Dissertations

Date

2022

Document Type

Thesis

Degree Name

Master of Science

Department

Biomedical Engineering

Committee Chair

Carl Herickhoff

Committee Member

Aaryani Tipirneni-Sajja

Committee Member

Bradford Pendley

Committee Member

Brent Hoffmeister

Abstract

Ultrasound localization microscopy (ULM) is a super-resolution vascular imaging technique that tracks the position of individual circulating microbubbles over time. Conventional ULM methods fit a gaussian 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 applied to channel RF data. 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 first for the case of focused-beam transmits over a range of F-numbers, and also 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.

Comments

Data is provided by the student.

Library Comment

Dissertation or thesis originally submitted to ProQuest.

Notes

Open access

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