Rapid FLASH scout and guidance lines for robust retrospective motion correction across all 2D TSE contrasts

Motivation: Motion remains a common source of artifacts in brain imaging. Goal(s): To facilitate retrospective motion correction across all 2D TSE contrasts. Approach: A 1-2 sec pre-scan (scout) using a saturation preparation and FLASH readout precedes the TSE imaging scan and is then compared to two additional rapid FLASH k-space encoding lines (guidance lines) inserted after every TSE echo train. The contrast-matched scout and guidance line data provide fully separable estimation of motion parameters shot-by-shot using a SENSE+motion model. Results: In vivo, rapid motion trajectory estimation and robust artifact mitigation is demonstrated in T1w, T2w and FLAIR TSE scans with instructed subject motion. Impact: We present a generalized strategy for retrospective motion correction in 2D TSE brain imaging using an ultra-fast pre-scan and the repeated acquisition of two additional k-space lines. This facilitates rapid motion estimation and robust artifact mitigation across all TSE contrasts.