Understanding phase maps in MRI: a new cutline phase unwrapping method.
This paper describes phase maps. A review of the phase unwrapping problem is given. Different structures, in particular fringelines, cutlines, and poles, contained within a phase map are described and their origin and behavior investigated. The problem of phase unwrapping can then be addressed with a better understanding of the source of poles or inconsistencies. This understanding, along with some assumptions about what is being encoded in the phase of a magnetic resonance image, are used to derive a new method for phase unwrapping which relies only on the phase map. The method detects cutlines and distinguishes between noise-induced poles and signal undersampling poles based on the length of the fringelines. The method was shown to be robust to noise and successful in unwrapping challenging clinical cases.
Chavez
Sofia
S
Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T IZI, Canada.
Xiang
Qing-San
QS
An
Li
L
D000465:Algorithms; D001783:Blood Flow Velocity; D018780:Body Surface Potential Mapping / Q000379:methods; D003198:Computer Simulation; D003326:Coronary Circulation / Q000502:physiology; D006321:Heart / Q000033:anatomy & histology / Q000502:physiology; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009038:Motion; D012815:Signal Processing, Computer-Assisted; D013269:Stochastic Processes