Premium
Referenceless multi‐channel signal combination: A demonstration in chemical‐shift‐encoded water‐fat imaging
Author(s) -
Liu Simin,
Wu Peng,
Liu Haining,
Hu Zhangxuan,
Guo Hua
Publication year - 2020
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.28028
Subject(s) - robustness (evolution) , channel (broadcasting) , algorithm , electromagnetic coil , signal (programming language) , phase (matter) , computer science , mathematics , biological system , physics , chemistry , telecommunications , biochemistry , quantum mechanics , gene , programming language , biology
Purpose Without explicit coil sensitivity information acquired by means of a reference body coil, multi‐channel signal combination for water‐fat separation (WFS) can be challenging due to channel‐dependent phase offsets and chemical‐shift dependent phase shifts. This study aims to develop a referenceless, robust, accurate, and fast channel combination method for WFS. Theory and Methods A dual‐step multi‐channel combination method is proposed. In the first step, channel‐dependent phase offsets are estimated with a preliminary WFS estimation. In the second step, the multi‐channel data are combined after removing phase offsets. Thereafter, WFS is performed to obtain final results. Numerical simulations (4–64 coils) and in vivo experiments (8, 16, 28 coils) at 3T field strength are conducted to compare the proposed method to previous methods. Channel combination with a body‐coil scan serves as the reference for in vivo experiments. Results The proposed method estimates channel‐dependent phase offsets accurately. It shows improved robustness to phase singularities than weighted mean and adaptive reconstruction. It is faster than adaptive reconstruction (e.g., 25.45 versus 46.34 s with 28 coils) and the channel‐by‐channel WFS method (e.g., 21.77 versus 50.04 s with 8 coils). It provides comparable fat quantification accuracy to the reference under various reasonable signal‐to‐noise ratio conditions (e.g., Pearson correlation coefficient r = 0.981 with P < 0.01, for in vivo fat fractions using flip angle = 10°). Conclusion The proposed referenceless channel combination method may be beneficial to both qualitative and quantitative water‐fat imaging.