Abstract: MRI signals from two species such as fat and water are separated by repeatedly applying a steady state free precession (SSFP) sequence to an object with the phase of each RF excitation pulse in a sequence being increased by 2?n/N radians on each repetition, where acquisition number n ranges from 1 to N. Alternatively, center frequency for each scan is incremented compared with the first scan center frequency. Images are reconstructed from the acquired signals and summed. Slowing varying phase due to sources other than chemical shift can be removed. Species signals are separated based on phase (sign) of the summed image signals.

Abstract: Artifact reduction in steady state free precession magnetic resonance imaging uses weighting of acquired image data to emphasize higher signals and then establishing an image signal based on the combined weighted signals. In one embodiment, a SSFP imaging sequence uses phase cycling and acquired image data is squared with the squared data then combined. The final image signal is based on the square root of the squared data.