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Susceptibility phase imaging with improved image contrast using moving window phase gradient fitting and minimal filtering
Author(s) -
Walsh Andrew J.,
Eissa Amir,
Blevins Gregg,
Wilman Alan H.
Publication year - 2012
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.23768
Subject(s) - phase (matter) , artificial intelligence , computer science , contrast (vision) , phase contrast imaging , mathematics , pattern recognition (psychology) , computer vision , phase contrast microscopy , optics , physics , quantum mechanics
Purpose: To enhance image contrast in susceptibility phase imaging using a new method of background phase removal. Materials and Methods: A background phase removal method is proposed that uses the spatial gradient of the raw phase image to perform a moving window third‐order local polynomial estimation and correction of the raw phase image followed by minimal high pass filtering. The method is demonstrated in simulation, 10 healthy volunteers, and 5 multiple sclerosis patients in comparison to a standard phase filtering approach. Results: Compared to standard phase filtering, the new method increased phase contrast with local background tissue in subcortical gray matter, cortical gray matter, and multiple sclerosis lesions by 67% ± 33%, 13% ± 7%, and 48% ± 19%, respectively (95% confidence interval). In addition, the new method removed more phase wraps in areas of rapidly changing background phase. Conclusion: Local phase gradient fitting combined with minimal high pass filtering provides better tissue depiction and more accurate phase quantification than standard filtering. J. Magn. Reson. Imaging 2012; 36:1460–1469. © 2012 Wiley Periodicals, Inc.