Towards rapid and accurate navigators for motion and B0 estimation using QUEEN (QUantitatively-Enhanced parameter Estimation from Navigators)

‘Scout-based’ navigators exploit correlations between navigator data and a low-resolution multi-coil pre-scan data (scout) to effectively estimate either motion or B0-perturbations. Usually, scout data has a fixed contrast, limiting their usage in estimating motion within echo-trains where contrast changes from one readout to the next (e.g. MPRAGE). Furthermore, combined motion and B0-perturbation estimation from rapid navigators has yet to be achieved. In this work, we propose a quantitative scout (Q-SCOUT) to ‘time-resolve’ navigator contrast, along with a rapid SPINS-navigator (few ms). Q-SCOUT and rapid navigator data are used in our QUEEN method to enable within-echo-train motion and B0-perturbation estimation.