Motivation: Bright fat signal in time-of-flight (TOF) MRA interferes with the visualization of vessels. Multi-point Dixon water-fat imaging may be used to suppress fat but at a cost of longer scan time. Goal(s): To demonstrate the feasibility of a scan efficient water-fat separation approach for Cartesian and spiral TOF MRA. Approach: After raw images were exported from the scanner, the off-resonance phase and background phase were estimated and removed. Water and fat were calculated with a combined method of phase-sensitive approach and single-point Dixon. Results: Water and fat were successfully separated at various TEs using half of the scan time of two-point Dixon. Impact: The proposed method improves background suppression for TOF with flexible TE options at negligible cost of scan time. Visualization of blood flow can be enhanced due to the feasible shorter TE as well as the sufficient fat suppression.
Wang et al. (Tue,) studied this question.