2026-09-20T08:09:05Z https://www.ideals.illinois.edu/oai-pmh

oai:www.ideals.illinois.edu:2142/108675 2023-07-11 col_2142_5131 col_2142_8888 com_2142_5130 com_2142_8887 com_2142_234

Bresler, Yoram Soylu, Ufuk 2020-10-07T22:49:48Z 2020-10-07T22:49:48Z 2022-10-07T22:50:13Z 2020-07-08 2020-08 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. Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2022-08-01 The student, Ufuk Soylu, accepted the attached license on 2020-07-07 at 16:01. The student, Ufuk Soylu, submitted this Thesis for approval on 2020-07-07 at 16:51. This Thesis was approved for publication on 2020-07-08 at 14:37. DSpace SAF Submission Ingestion Package generated from Vireo submission #15515 on 2020-10-02 at 15:49:54 Made available in DSpace on 2020-10-07T22:49:48Z (GMT). No. of bitstreams: 2 SOYLU-THESIS-2020.pdf: 8154525 bytes, checksum: 7a33435e4bebd295579bd34670a44088 (MD5) LICENSE.txt: 4207 bytes, checksum: 145f5a4b8f987861a2f3eab0ff785388 (MD5) Previous issue date: 2020-07-08 Embargo set by: Seth Robbins for item 116304 Lift date: 2022-10-07T22:50:13Z Reason: Author requested closed access (OA after 2yrs) in Vireo ETD system Author requested closed access (OA after 2yrs) in Vireo ETD system Limited application/pdf http://hdl.handle.net/2142/108675 en Copyright 2020 Ufuk Soylu Ultrasound Localization Microscopy Signal Processing Velocity Filtering A signal processing approach to ultrasound localization microscopy text Thesis Electrical & Computer Eng Electrical & Computer Engr University of Illinois at Urbana-Champaign Thesis M.S.