Title: Performance of chemical shift-based water-fat separation with self-calibrated fat spectrum is sensitive to echo times

Authors: Xinwei Shi; Hua Guo

Addresses: Department of Biomedical Engineering, Center for Biomedical Imaging Research, School of Medicine, Tsinghua University, Beijing, China ' Department of Biomedical Engineering, Center for Biomedical Imaging Research, School of Medicine, Tsinghua University, Beijing, China

Abstract: Chemical shift-based water-fat separation method utilises water-fat resonance frequency difference to decompose signals into water and fat partitions in magnetic resonance imaging (MRI) on a pixel-wise basis. It provides an effective way to measure fat fraction, or to suppress fat signal which might obscure underlying pathology. IDEAL (Iterative decomposition of water and fat with echo asymmetry and least-squares estimation) algorithm with multi-peak fat spectral modelling has been developed. Recent studies have discussed the performance of this algorithm assuming that the frequencies and relative amplitudes of fat peaks are constant among all subjects. However, the fat spectra vary in different tissues, thus a self-calibration method which estimates the fat spectrum directly from the data provides more accurate results. In this work, we analyse the performance of multi-peak IDEAL algorithm with self-calibrated fat spectrum by theoretical calculation, simulation, and experiments, and find optimal echo time increments which provide reliable water-fat separation.

Keywords: MRI; magnetic resonance imaging; fat-water separation; fat fraction; IDEAL; self-calibrated multi-peak fat spectral modelling; CRB; Cramer-Rao bound; chemical shift; echo times; simulation.

DOI: 10.1504/IJCBDD.2013.055461

International Journal of Computational Biology and Drug Design, 2013 Vol.6 No.3, pp.244 - 254

Published online: 29 Jul 2013 *

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