Correction for T1 Determined Using Rapid Look-Locker b-SSFP and a Simple Two Parameter Model Fit

Introduction: Multiple acquisitions along the longitudinal magnetization curve as done with the Look-Locker (LL) technique perturbs the inversion recovery curve. The b-SSFP sequence perturbs magnetization minimally compared to other sequences [1]. However, when inversion recovery is incomplete (if TRseq<5T1max) or the flip angle is relatively large (>10° for GM/WM/CSF mapping), a three parameter model needs to be used to obtain correct T1 values [2]. A drawback though is that about six to ten LL phases are needed for a good fit. This compromises scan time or resolution. To improve temporal efficiency, ideally one would like to acquire the fewest number of phases allowed by the model. A scheme that corrects for modulated and/or incomplete inversion recovery using a simple two parameter model with three acquired phases is presented here. Factors affecting the accuracy of the proposed correction for T1 are also discussed here.