title: Intra- and interhemispheric variations of diffusivity in subcortical white matter in normal human brain.
abstract: Our purpose was to reveal potential regional variations in water molecular diffusivity within each cerebral hemisphere and across the right and left hemispheres. Diffusion-weighted images of 44 healthy right-handed adult male subjects were obtained using a diffusion tensor imaging sequence. Mean diffusivity (MD) values in subcortical white matter (WM) within 39 regions in each hemisphere were measured using an automated method. Intrahemispheric comparisons of MDs in subcortical WM were performed among six brain regions (frontal, parietal, occipital and temporal lobes and pre- and postcentral gyri). Interhemispheric comparisons of MDs were performed between the right and left counterparts of the 39 regions. In both hemispheres, diffusivity in the precentral gyrus was lower than those in other regions, while diffusivity in the parietal lobe was higher than others. MD asymmetry in which the left was lower than the right was found in the parietal lobe, middle occipital gyrus, and medial and orbital aspects of the frontal lobe. The converse asymmetry was revealed in the frontal operculum, supplementary motor cortex, temporal lobe, limbic cortices, precuneus and cuneus. Our results revealed significant intra- and interhemispheric regional variations in MD in subcortical WM, which may be related to different densities of axons and myelin sheaths.
authors: Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan. tyoshiu@med.kyushu-u.ac.jp
authors: Takashi
authors: T
authors: Yoshiura
authors: Tomoyuki
authors: T
authors: Noguchi
authors: Akio
authors: A
authors: Hiwatashi
authors: Osamu
authors: O
authors: Togao
authors: Koji
authors: K
authors: Yamashita
authors: Eiki
authors: E
authors: Nagao
authors: Hironori
authors: H
authors: Kamano
authors: Hiroshi
authors: H
authors: Honda
mesh_terms: D000328:Adult; D001834:Body Water / Q000378:metabolism*; D001921:Brain / Q000033:anatomy & histology* / Q000378:metabolism*; D004058:Diffusion; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009413:Nerve Fibers, Myelinated / Q000378:metabolism* / Q000648:ultrastructure; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014867:Water / Q000378:metabolism*
chemical_list: D014867:Water