Phase-Unwrapping based on Graph-Cuts for Low-venc Phase-Contrast Cine MRI

The use of low velocity encoding (venc) improves the velocity-to-noise ratio in phase-contrast MRI, but increases the risk of phase wrapping. A novel phase-unwrapping technique based on graph-cuts was evaluated in five cardiac patients with high-, medium-, and low-venc acquisitions. The proposed method reduced the stroke volume error compared to a LaPlacian based reference method. In retrospectively wrapped data, the proposed method demonstrated excellent unwrapping results in most cases, even for venc as low as 25 cm/s. The graph-cut based method appears promising for low-venc acquisitions combined with phase-unwrapping.