Prospective motion correction for brain MRI using spherical navigators

Purpose To demonstrate for the first time the feasibility of performing prospective motion correction using spherical navigators (SNAVs). Methods SNAVs were interleaved in a 3D FLASH sequence with an additional short baseline scan (6.8 s) for fast rotation estimation. Assessment of SNAV‐based prospective motion correction was performed in six volunteers. Participant motion was guided using randomly generated stepwise prompts as well as prompts derived from real motion cases. Experiments were performed on a 3 T MRI scanner using a 32‐channel head coil. Results When optimized for real‐time application, SNAV‐based motion estimates were computed in 25.8 ± 1.3 ms. Phantom‐based quantification of rotation and translation accuracy indicated mean absolute errors of 0.10 ± 0.09° and 0.25 ± 0.14 mm, respectively. Implementing SNAV‐based motion estimates for prospective motion correction led to a clear improvement in image quality with minimal increase in scan time (