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Proceedings Paper

Optimized motion estimation for MRE data with reduced motion encodes
Author(s): Huifang Wang; John B. Weaver; Marvin M. Doyley; Qing Feng; Francis E. Kennedy; Keith D. Paulsen
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Paper Abstract

Motion estimation is an essential processing step common to all Magnetic Resonance Elastography (MRE) methods. For dynamic techniques, the motion is obtained from a sinusoidal fit of the image phase at multiple, uniformly spaced relative phase offsets, φ, between the motion and the motion encoding gradients (MEGs). Generally, 4 to 8 uniformly spaced values of φ are used. We introduce a method, termed RME (reduced motion encodes), of reducing the number of relative phases required, thereby reducing the imaging time for an MRE acquisition. A frequency-domain algorithm was implemented using the Discrete Fourier Transform (DFT) to derive the general least-squares solution for the motion amplitude and phase given an arbitrary number of phase offsets. Simulation result shows that the noise level decreases as the number of φ increases. The decrease is largest when smaller numbers of φ are used and becomes less significant as the number increases. The minimum noise is obtained for a specific number, n, of φ when the phase is evenly distributed with interval π/n. Phantom studies show a similar trend with noise level. The resulting displacement images from different numbers of phase offsets are compared.

Paper Details

Date Published: 13 March 2006
PDF: 9 pages
Proc. SPIE 6143, Medical Imaging 2006: Physiology, Function, and Structure from Medical Images, 614325 (13 March 2006); doi: 10.1117/12.650135
Show Author Affiliations
Huifang Wang, Dartmouth College (United States)
John B. Weaver, Dartmouth College (United States)
Dartmouth Hitchcock Medical Ctr. (United States)
Marvin M. Doyley, Dartmouth College (United States)
Dartmouth Hitchcock Medical Ctr. (United States)
Qing Feng, Medical Metrx Solutions (United States)
Francis E. Kennedy, Dartmouth College (United States)
Keith D. Paulsen, Dartmouth College (United States)
Norris Cotton Cancer Ctr. (United States)

Published in SPIE Proceedings Vol. 6143:
Medical Imaging 2006: Physiology, Function, and Structure from Medical Images
Armando Manduca; Amir A. Amini, Editor(s)

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