Determination of optimal angles for variable nutation proton magnetic spin-lattice, T1, and spin-spin, T2, relaxation times measurement

Abstract

T1 and T2 can be rapidly determined with a combination of multiangle spoiled gradient recalled echo (SPGR) and steady-state free precession (SSFP) imaging. Previously, we demonstrated a simple method for determining the set of SPGR and SSFP angles that provided greater T1 and T2 precision than a set of uniformly spaced angles. In this article a more rigorous approach for determining angles is described. Weighted least-squares is also introduced for T1 and T2 estimation and a novel weighting function described. This new approach, suited for imaging applications where large T1 and T2 ranges are anticipated, provides high and uniform precision over a wide range of T1 and T2 values.