A method for automatic identification of water and fat images from a symmetrically sampled dual-echo Dixon technique

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• 作者：Moiz Ahmad ; Yinan Liu ; Zachary W. Slavens ; Russell Low ; Elmar Merkle ; Ken-Pin Hwang ; Anthony Vu ; Jingfei Ma
• 关键词：Dixon imaging ; Symmetric sampling ; Water and fat identification ; Fat spectra
• 刊名：Magnetic Resonance Imaging
• 出版年：2010
• 出版时间：April 2010
• 年：2010
• 卷：28
• 期：3
• 页码：427-433
• 全文大小：531 K

文摘

Sampling water and fat signals symmetrically (i.e., at 0° and 180° relative phase angles) in a dual-echo Dixon technique offers high intrinsic tolerance to phase fluctuations in postprocessing and maximum signal-to-noise performance for the separated water and fat images. However, identification of which image is water and which image is fat after their separation is not possible based on the phase information alone. In this work, we proposed a semiempirical automatic image identification method that is based on the intrinsic asymmetry between the water and fat chemical shift spectra. Specifically, the approximately bimodal feature of the fat spectra and the observation that most in vivo tissues are either predominantly water or predominantly fat are used to construct a spectrum-based algorithm. Additional refinement is accomplished by considering the spatial distribution of the tissues that may have a coexistence of water and fat. The final improved algorithm was tested on a total of 131 three-dimensional patient datasets collected from different scanners and found to yield correct water and fat identification in all datasets.