In vivo multiecho T-2 relaxation measurements using variable TR to decrease scan time

TitleIn vivo multiecho T-2 relaxation measurements using variable TR to decrease scan time
Publication TypeJournal Article
Year of Publication2007
AuthorsLaule, C., S. H. Kolind, T. A. Bjarnason, D. K. B. Li, and A. L. MacKay
JournalMagnetic Resonance Imaging

Multiecho T-2 relaxation measurements to determine geometric mean T-2 (GMT(2)) and myelin water fraction (MWF) are lengthy, resulting in increased motion artefacts from patient discomfort and reduced patient compliance. The goal of this study was to shorten the acquisition time for multiecho T-2 measurements without affecting T-1 weighting by varying T-R across k-space. Six phantoms and 10 healthy volunteers were imaged with both a constant TR and a variable TR multiecho T-2 sequence. T-1 weighting was determined by TR at the center of k-space; for variable TR measurement, TR was shortened linearly from the center to the edges of k-space. Phantoms showed excellent agreement for proton density and GMT(2) between constant and variable TR measurements. No significant differences were found in proton density or MWF for any of the brain structures between the two measurements. The average GMT(2) over all structures between the two experiments was not significantly different. In summary, with the variable TR approach, scan time was reduced by > 20%, with minimal loss of image resolution and no significant affect on proton density, MWF or GMT(2). (c) 2007 Elsevier Inc. All rights reserved.


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