title: Effects of echo time on diffusion quantification of brain white matter at 1.5 T and 3.0 T.
abstract: The aim was to investigate the effects of echo time (TE) on diffusion quantification of brain white matter. Seven rhesus monkeys (all males; age, 4-6 years; weight, 5-7 kg) underwent diffusion tensor imaging (DTI) with a series of TEs in 1.5 T and 3.0 T MR scanners. The mean diffusivity (MD), fractional anisotropy (FA), primary (lambda(1)), and transverse eigenvalues (lambda(23)) were measured in a region of interest at the bilateral internal capsule. Pearson correlation showed that the FA and lambda(1) increased and lambda(23) decreased with TE both at 1.5 T and 3.0 T except for the MD. Repeated measurement analysis of variance (ANOVA) also showed significantly higher FA and lower MD and lambda(23) at 3.0 T than those at 1.5 T (P<0.01), but no statistical differences were found in lambda(1) between these two field strengths (P=0.709). These findings implied that TE and field strength might influence diffusion quantification in brain white matter.
authors.affiliation: Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing, China.
authors.forename: Wen
authors.initials: W
authors.lastname: Qin
authors.forename: Chun Shui
authors.initials: CS
authors.lastname: Yu
authors.forename: Fan
authors.initials: F
authors.lastname: Zhang
authors.forename: Xiang Ying
authors.initials: XY
authors.lastname: Du
authors.forename: Heng
authors.initials: H
authors.lastname: Jiang
authors.forename: Yu Xia
authors.initials: YX
authors.lastname: Yan
authors.forename: Kun Cheng
authors.initials: KC
authors.lastname: Li
mesh_terms: D000465:Algorithms; D000818:Animals; D001921:Brain / Q000166:cytology*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008253:Macaca mulatta; D009413:Nerve Fibers, Myelinated / Q000648:ultrastructure*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity