title: Fractional anisotropy and mean diffusivity: comparison between 3.0-T and 1.5-T diffusion tensor imaging with parallel imaging using histogram and region of interest analysis.
abstract: We performed a comparison study focusing on differences in fractional anisotropy (FA) and mean diffusivity (MD) between 3-T and 1.5-T diffusion tensor imaging (DTI) with parallel imaging. Thirty healthy volunteers underwent DTI with an eight-channel phased-array coil at both 3 T and 1.5 T. Histogram and region of interest (ROI) analyses were performed. Paired t tests were applied for statistical analysis. Signal-to-noise ratios of these regions were also measured. For histogram analysis, peak location of FA was significantly lower at 3 T than at 1.5 T (P = 0.04). Mean FA was significantly higher at 3 T than at 1.5 T (P = 0.002). Peak location of MD was significantly lower at 3 T than at 1.5 T (P < 0.001). Mean MD was significantly lower at 3 T than at 1.5 T (P < 0.001). In ROI analysis, FA was significantly larger at 3 T than at 1.5 T in the centrum semiovale (P < 0.001), middle cerebellar peduncle (P < 0.001), cerebral peduncle (P = 0.006), posterior limb of the internal capsule (P = 0.007), genu (P < 0.001) and splenium (P < 0.001). FA was significantly lower at 3 T than at 1.5 T in the globus pallidus (P < 0.001). MD was significantly smaller at 3 T than at 1.5 T in the globus pallidus (P = 0.007), thalamus (P < 0.001), centrum semiovale (P < 0.001), middle cerebellar peduncle (P < 0.001), cerebral peduncle (P = 0.01), posterior limb of the internal capsule (P < 0.001), genu (P = 0.01) and splenium (P < 0.001). Significant differences in FA and MD exist between 3 T and 1.5 T for whole-brain histogram analysis and ROI analysis.
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Yasutaka
authors.initials: Y
authors.lastname: Fushimi
authors.forename: Yukio
authors.initials: Y
authors.lastname: Miki
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Okada
authors.forename: Akira
authors.initials: A
authors.lastname: Yamamoto
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Mori
authors.forename: Takashi
authors.initials: T
authors.lastname: Hanakawa
authors.forename: Shin-Ichi
authors.initials: S
authors.lastname: Urayama
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Aso
authors.forename: Hidenao
authors.initials: H
authors.lastname: Fukuyama
authors.forename: Ken-Ichiro
authors.initials: K
authors.lastname: Kikuta
authors.forename: Kaori
authors.initials: K
authors.lastname: Togashi
mesh_terms: D000328:Adult; D016880:Anisotropy; D002531:Cerebellum / Q000033:anatomy & histology*; D004058:Diffusion; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009928:Organ Specificity