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Rapid and accurate T 2 mapping from multi–spin‐echo data using Bloch‐simulation‐based reconstruction
Author(s) -
BenEliezer Noam,
Sodickson Daniel K.,
Block Kai Tobias
Publication year - 2015
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.25156
Subject(s) - computer science , imaging phantom , echo (communications protocol) , scanner , voxel , spin echo , range (aeronautics) , relaxation (psychology) , matching (statistics) , artificial intelligence , contrast (vision) , field (mathematics) , computer vision , algorithm , physics , magnetic resonance imaging , mathematics , optics , materials science , statistics , medicine , psychology , computer network , social psychology , composite material , radiology , pure mathematics
Purpose Quantitative 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. Methods Bloch 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. Results T 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. Conclusion The 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. © 2014 Wiley Periodicals, Inc.