Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6027985 | NeuroImage | 2014 | 18 Pages |
Abstract
Nuclear magnetic resonance (NMR) relaxation in the rotating frame is sensitive to molecular dynamics on the time scale of water molecules interacting with macromolecules or supramolecular complexes, such as proteins, myelin and cell membranes. Hence, longitudinal (T1Ï) and transverse (T2Ï) relaxation in the rotating frame may have a great potential to probe the macromolecular fraction of tissues. This stimulated a large interest in using this MR contrast to image brain under healthy and disease conditions. However, experimental challenges related to the use of intense radiofrequency irradiation have limited the widespread use of T1Ï and T2Ï imaging. Here, we present methodological development to acquire 3D high-resolution or 2D (multi-)slice selective T1Ï and T2Ï maps of the entire human brain within short acquisition times. These improvements are based on a class of gradient modulated adiabatic pulses that reduce the power deposition, provide slice selection, and mitigate artifacts resulting from inhomogeneities of B1 and B0 magnetic fields. Based on an analytical model of the T1Ï and T2Ï relaxation we compute the maps of macromolecular bound water fraction, correlation and exchange time constants as quantitative biomarkers informative of tissue macromolecular content. Results obtained from simulations, phantoms and five healthy subjects are included.
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Cognitive Neuroscience
Authors
Ovidiu C. Andronesi, Himanshu Bhat, Martin Reuter, Shreya Mukherjee, Peter Caravan, Bruce R. Rosen,