Determination of optimal angles for variable nutation proton magnetic spin-lattice, T1, and spin-spin, T2, relaxation times measurement.
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.
Deoni
Sean C L
SC
Imaging Research Laboratories, Robarts Research Institute, London, Ontario, Canada.
Peters
Terry M
TM
Rutt
Brian K
BK
D000465:Algorithms; D001921:Brain / Q000033:anatomy & histology*; D003198:Computer Simulation; D006801:Humans; D016018:Least-Squares Analysis; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008962:Models, Theoretical; D011522:Protons
D011522:Protons