Motion artifact suppression technique (MAST) for cranial MR imaging: superiority over cardiac gating for reducing phase-shift artifacts.

A motion artifact suppression technique (MAST) has recently been developed that significantly reduces motion artifacts in conventional 2DFT imaging. The technique utilizes modifications of slice-select and read gradient waveforms to eliminate velocity, acceleration, and pulsatility phase shifts that occur between the 90 degrees pulse and data collection. T2-weighted cranial MAST images were rated visually superior to cardiac-gated images by two experienced neuroradiologists in 13 of 15 cases and in 14 of 15 cases, respectively (p less than 0.001). Quantitative signal-to-noise comparisons for six brain regions in each patient confirmed the visually apparent superiority of MAST, especially for imaging the brainstem and subarachnoid cisterns (p = 0.02). Improvements in signal-to-noise ratios of up to 43% were obtained when using MAST instead of cardiac gating. MAST or a similar technique has the potential to render cardiac gating obsolete as a method for reducing flow-related artifacts in cranial MR imaging.