Feasibility of water-fat separated free-running 3D cardiac cine imaging with a phase-sensitive approach

Motivation: Water-fat separated (WFS) imaging can improve detection and characterization of various cardiovascular pathologies. We hypothesize that the signal phase at half the repetition time of balanced steady-state free precession (bSSFP) may be used for efficient WFS cine imaging. Goal(s): To study the feasibility of WFS free-running 3D cardiac cine imaging using the phase-sensitive approach. Approach: After reconstruction of 5D whole heart images, the global slowly varying phase was estimated and removed. Water and fat voxels were then identified according to the phase. Results: Water and fat were sufficiently separated around the heart. A field map of off-resonance can partially mitigate peripheral water/fat swaps. Impact: A phase sensitive approach for WFS only requires negligible computational cost and minor adjustment of repetition time. It might be implemented with a wide range of bSSFP cine imaging techniques for fat suppression or to provide complementary water/fat information.