title: Rapid and accurate T2 mapping from multi-spin-echo data using Bloch-simulation-based reconstruction.
abstract: OBJECTIVE
  Quantitative T2 -relaxation-based contrast has the potential to provide valuable clinical information. Practical T2 -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 T2 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 T2 values and transmit field scales, yielding a database of simulated EMCs, which is then used to identify the T2 value whose EMC most closely matches the experimentally measured data at each voxel.
  
  
  RESULTS
  T2 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 T2 values and across different experimental settings.
  
  
  CONCLUSIONS
  The proposed technique allows accurate T2 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., T1 , B1 (+) , B0 , diffusion) and support arbitrary acquisition schemes.
authors.affiliation: The Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York, University School of Medicine, New York, New York, USA.
authors.forename: Noam
authors.initials: N
authors.lastname: Ben-Eliezer
authors.forename: Daniel K
authors.initials: DK
authors.lastname: Sodickson
authors.forename: Kai Tobias
authors.initials: KT
authors.lastname: Block
mesh_terms: D000465:Algorithms; D001921:Brain / Q000033:anatomy & histology*; D017352:Echo-Planar Imaging / Q000379:methods*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D016247:Information Storage and Retrieval / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013113:Spin Labels
chemical_list: D013113:Spin Labels
keywords: T2 mapping; quantitative MRI