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Fast high‐resolution T 1 mapping of the human brain
Author(s) -
Deichmann Ralf
Publication year - 2005
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.20552
Subject(s) - flip angle , multislice , magnetization transfer , nuclear magnetic resonance , dynamic range , excitation , physics , materials science , optics , image resolution , magnetic resonance imaging , medicine , quantum mechanics , radiology
Abstract A sequence for the acquisition of high‐resolution T 1 maps, based on magnetization‐prepared multislice fast low‐angle shot (FLASH) imaging, is presented. In contrast to similar methods, no saturation pulses are used, resulting in an increased dynamic range of the relaxation process. Furthermore, it is possible to acquire data during all relaxation delays because only slice‐selective radiofrequency (RF) pulses are used for inversion and excitation. This allows for a reduction of the total acquisition time, or scanning with a reduced bandwidth, which improves the signal‐to‐noise ratio (SNR). The method generates quantitative T 1 maps with an in‐plane resolution of 1 mm, slice thickness of 4 mm, and whole‐brain coverage in a clinically acceptable imaging time of about 19 s per slice. It is shown that the use of off‐center RF pulses does not result in imperfect inversion or magnetization transfer (MT) effects. In addition, an improved fitting algorithm based on smoothed flip angle maps is presented and tested successfully. Magn Reson Med 54:20–27, 2005. © 2005 Wiley‐Liss, Inc.