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Transverse relaxometry with reduced echo train lengths via stimulated echo compensation
Author(s) -
Uddin Md. Nasir,
Marc Lebel R.,
Wilman Alan H.
Publication year - 2013
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.24568
Subject(s) - multislice , echo (communications protocol) , nuclear magnetic resonance , magnetization transfer , specific absorption rate , spin echo , relaxometry , grey matter , physics , white matter , magnetic resonance imaging , chemistry , computer science , telecommunications , medicine , radiology , computer network , antenna (radio)
Transverse relaxation ( T 2 ) mapping has many applications, including imaging of iron accumulation in grey matter. Using the typical multiecho spin‐echo sequence with long echo trains, stimulated echo compensation can enable T 2 fitting under conditions of variable radio frequency homogeneity arising from slice profile and in‐plane radio frequency variation. Substantial reduction in the number of refocusing pulses could enable use at high magnetic fields where specific absorption rate is a major limitation, and enable multislice use with reduced incidental magnetization transfer at all field strengths. We examine the effect of reduced echo train lengths and multislice imaging on T 2 fitting using stimulated echo compensation applied to iron‐rich subcortical grey matter in human brain at 4.7 T. Our findings indicate that reducing from 20 echoes to as few as four echoes can maintain consistent T 2 values when using stimulated echo compensation in grey and white matter, but not for cerebrospinal fluid. All territories produce marginal results when using standard exponential fitting. Savings from reduced echoes can be used to substantially increase slice coverage. In multislice mode, the resulting incidental magnetization transfer decreased brain signal but had minimal effect on measured T 2 values. Magn Reson Med 70:1340–1346, 2013. © 2013 Wiley Periodicals, Inc.