Navigator-Assisted Fast Motion-Compensated Brain MRI

Motivation: To bring motion-compensated brain MRI closer to clinical reality by reducing reconstruction times. Goal(s): Assess the impact of motion-estimation from navigators on initializing retrospective motion-compensated image reconstruction. Approach: A segmented, magnetization-prepared gradient-echo sequence was modified to include navigators. Motion parameters were estimated from the navigators and used to define motion-segments and to initialize the motion-compensated iterative reconstruction. Results: Compared to the baseline approach, the navigator-assisted approach allows to use about 50% fewer motion-segments at the same image quality and needs less than quarter of the iterations to converge. Impact: Making accurate and fast motion-compensated brain MRI without additional devices available will reduce costs associated with non-diagnostic images and resulting rescans.