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Dynamic diffusion‐tensor measurements in muscle tissue using the single‐line multiple‐echo diffusion‐tensor acquisition technique at 3T
Author(s) -
Baete Steven H.,
Cho Gene Y.,
Sigmund Eric E.
Publication year - 2015
Publication title -
nmr in biomedicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.278
H-Index - 114
eISSN - 1099-1492
pISSN - 0952-3480
DOI - 10.1002/nbm.3296
Subject(s) - diffusion mri , fractional anisotropy , imaging phantom , diffusion , tensor (intrinsic definition) , anisotropy , biomedical engineering , nuclear magnetic resonance , scanner , physics , magnetic resonance imaging , mathematics , medicine , optics , geometry , radiology , thermodynamics
When diffusion biomarkers display transient changes, i.e. in muscle following exercise, traditional diffusion‐tensor imaging (DTI) methods lack the temporal resolution to resolve the dynamics. This article presents an MRI method for dynamic diffusion‐tensor acquisitions on a clinical 3T scanner. This method, the Single‐Line Multiple‐Echo Diffusion‐Tensor Acquisition Technique (SL‐MEDITATE), achieves a high temporal resolution (4 s) by [1][Basser P, 1994] rapid diffusion encoding through the acquisition of multiple echoes with unique diffusion sensitization and [2][Alexander A, 2000] limiting the readout to a single line volume. The method is demonstrated in a rotating anisotropic phantom, a flow phantom with adjustable flow speed and in vivo skeletal calf muscle of healthy volunteers following a plantar flexion exercise. The rotating and flow‐varying phantom experiments show that SL‐MEDITATE correctly identifies the rotation of the first diffusion eigenvector and the changes in diffusion‐tensor parameter magnitudes, respectively. Immediately following exercise, the in vivo mean diffusivity (MD) time courses show, before the well‐known increase, an initial decrease that is not typically observed in traditional DTI. In conclusion, SL‐MEDITATE can be used to capture transient changes in tissue anisotropy in a single line. Future progress might allow for dynamic DTI when combined with appropriate k ‐space trajectories and compressed sensing reconstruction. Copyright © 2015 John Wiley & Sons, Ltd.