Rapid and Accurate T2 Mapping from Multi-Spin-Echo Data Using Bloch-Simulation-Based Reconstruction

PurposeQuantitative T-2-relaxation-based contrast has the potential to provide valuable clinical information. Practical T-2-mapping, however, is impaired either by prohibitively long acquisition times or by contamination of fast multiecho protocols by stimulated and indirect echoes. This work presents a novel postprocessing approach aiming to overcome the common penalties associated with multiecho protocols, and enabling rapid and accurate mapping of T-2 relaxation values. MethodsBloch simulations are used to estimate the actual echo-modulation curve (EMC) in a multi-spin-echo experiment. Simulations are repeated for a range of T-2 values and transmit field scales, yielding a database of simulated EMCs, which is then used to identify the T-2 value whose EMC most closely matches the experimentally measured data at each voxel. ResultsT(2) maps of both phantom and in vivo scans were successfully reconstructed, closely matching maps produced from single spin-echo data. Results were consistent over the physiological range of T-2 values and across different experimental settings. ConclusionThe proposed technique allows accurate T-2 mapping in clinically feasible scan times, free of user- and scanner-dependent variations, while providing a comprehensive framework that can be extended to model other parameters (e.g., T-1, B-1(+), B-0, diffusion) and support arbitrary acquisition schemes. Magn Reson Med 73:809-817, 2015. (c) 2014 Wiley Periodicals, Inc.