Abstract
Purpose: In magnetic resonance-guided focused ultrasound (MRgFUS) therapies performed in highly heterogeneous tissues such as the breast, the focal location must be located and characterized to guide successful treatments of tumors. Treatment time can be minimized by a priori prediction of the focal location through computational models. The purpose of this work is to evaluate numerical simulations of focused ultrasound (FUS) on their predictions of the focal location. Those simulations are compared to clinical magnetic resonance acoustic radiation force imaging (MR-ARFI) data collected during in vivo treatment of breast tumors. Methods: The focal location was evaluated prior to MRgFUS treatment with MR-ARFI in five patients. Retrospective simulations of MR-ARFI were made by applying the hybrid angular spectrum (HAS) method to segmented 3D tissue models of the patients. Pressure fields from HAS simulations were converted to force fields, which were convolved with a 3D Green's function (with time-of-arrival weighting) to produce a simulation of the magnetic resonance acoustic radiation force imaging (MR-ARFI) measured displacement of the tissue. Results: The focal locations found by the simulations and the MR-ARFI measurements have good agreement, on average separated by 3.7 mm (SD 0.9 mm). Characterization of the focal zone spatial distributions have moderate agreement, with the normalized root mean squared difference 19.4% (SD: 8.1%) on average. The displacement magnitudes have poor agreement, with the simulations underestimating the MR-ARFI measurements by 82% (SD 5.6%) on average. Conclusions: The agreement between MR-ARFI experimental measurements and simulated results demonstrates that HAS can predict the focal location, which is the primary goal of these MR-ARFI simulations. Disagreement in the magnitude of the tissue displacement between the measurements and simulations informs the need for further work in tissue displacement modeling and tissue material property measurement.
Degree
MS
College and Department
Ira A. Fulton College of Engineering; Mechanical Engineering
Rights
https://lib.byu.edu/about/copyright/
BYU ScholarsArchive Citation
Nelson, Chloe K., "Evaluating Computational Predictions of Magnetic Resonance Acoustic Radiation Force Imaging for Breast Cancer Focused Ultrasound Surgery" (2024). Theses and Dissertations. 10897.
https://scholarsarchive.byu.edu/etd/10897
Date Submitted
2024-06-18
Document Type
Thesis
Handle
http://hdl.lib.byu.edu/1877/etd13733
Keywords
breast cancer, acoustic modeling, focused ultrasound, MR-ARFI, MRgFUS
Language
english