A signal processing approach to ultrasound localization microscopy

Soylu, Ufuk

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https://hdl.handle.net/2142/108675 Copy

Description

Title

A signal processing approach to ultrasound localization microscopy

Author(s)

Soylu, Ufuk

Issue Date

2020-07-08

Director of Research (if dissertation) or Advisor (if thesis)

Bresler, Yoram

Department of Study

Electrical & Computer Eng

Discipline

Electrical & Computer Engr

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• Ultrasound Localization Microscopy
• Signal Processing
• Velocity Filtering

Abstract

Ultrasound Localization Microscopy (ULM) offers a cost-effective modality for microvascular imaging by using intravascular contrast agents (microbubbles). However, ULM has a fundamental trade-off between acquisition time and spatial resolution, which makes clinical translation challenging. In this thesis, in order to circumvent the trade-off, we pose the localization problem as a signal processing problem and introduce a filtering operation that is capable of separating microbubble contrast agents into different subgroups based on their vector velocities while simultaneously offering blood velocity mapping at super resolution, without tracking individual microbubbles. We define the filtering operation in three-dimensional (3D) Fourier domain and provide rigorous theoretical analysis on the performance of the filtering operation. Numerical experiments validate that the proposed filtering method is able to separate the microbubbles with respect to the speed and direction of their motion. In combination with subsequent localization of microbubble centers, e.g. by matched filtering, velocity filter signicantly improves the quality of reconstructed vessel structure map and provides blood flow information. Overall, the proposed imaging pipeline in this thesis, eliminates the need of using diluted microbubble injections to improve image quality, thus helping to circumvent the trade-off between acquisition time and spatial resolution. Conveniently, because the velocity filtering operation can be implemented by fast Fourier transforms (FFTs) it admits fast, and potentially real-time realization. We believe that the proposed filtering method has the potential to pave the way to clinical translation of ULM.

Graduation Semester

2020-08

Type of Resource

Thesis

Permalink

http://hdl.handle.net/2142/108675

Copyright and License Information

Copyright 2020 Ufuk Soylu

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