title: RF inhomogeneity compensation in structural brain imaging.
abstract: Three-dimensional T(1)-weighted magnetization-prepared rapid gradient-echo (MP-RAGE) sequences with centric phase encoding (PE) in the inner loop provide structural brain images with a high spatial resolution and high tissue contrast. A disadvantage of this sequence type is the susceptibility to inhomogeneities of the radiofrequency (RF) coil, which may result in poor image contrast in some peripheral regions. A special excitation pulse is presented which compensates for these effects in both the head/foot and anterior/posterior directions. This pulse has a duration of only 1.3 ms and is thus compatible with the short repetition times (TRs) required for MP-RAGE imaging. It is shown experimentally that images acquired with the compensation pulse may be segmented without using intensity correction algorithms during data postprocessing.
authors.affiliation: Wellcome Department of Cognitive Neurology, Institute of Neurology, London, UK. r.deichmann@fil.ion.ucl.ac.uk
authors.forename: R
authors.initials: R
authors.lastname: Deichmann
authors.forename: C D
authors.initials: CD
authors.lastname: Good
authors.forename: R
authors.initials: R
authors.lastname: Turner
mesh_terms: D016477:Artifacts; D001921:Brain / Q000033:anatomy & histology*; D017352:Echo-Planar Imaging / Q000379:methods*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007091:Image Processing, Computer-Assisted; D012016:Reference Values; D012680:Sensitivity and Specificity