Phase unwrapping with graph cuts optimization and dual decomposition acceleration for 3D high‐resolution MRI data

Purpose Existence of low SNR regions and rapid-phase variations pose challenges to spatial phase unwrapping algorithms. Global optimization-based phase unwrapping methods are widely used, but are significantly slower than greedy methods. In this paper, dual decomposition acceleration is introduced to speed up a three-dimensional graph cut–based phase unwrapping algorithm. Methods The phase unwrapping problem is formulated as a global discrete energy minimization problem, whereas the technique of dual decomposition is used to increase the computational efficiency by splitting the full problem into overlapping subproblems and enforcing the congruence of overlapping variables. Using three dimensional (3D) multiecho gradient echo images from an agarose phantom and five brain hemorrhage patients, we compared this proposed method with an unaccelerated graph cut–based method. Results Experimental results show up to 18-fold acceleration in computation time. Conclusions Dual decomposition significantly improves the computational efficiency of 3D graph cut–based phase unwrapping algorithms. Magn Reson Med, 2016. © 2016 Wiley Periodicals, Inc.