Takashi Yoshiura MD, PhD, Presenter: Nothing to Disclose

Tomoyuki Noguchi, Abstract Co-Author: Nothing to Disclose

Akio Hiwatashi MD, Abstract Co-Author: Nothing to Disclose

Osamu Togao MD, Abstract Co-Author: Nothing to Disclose

Kouji Yamashita MD, Abstract Co-Author: Nothing to Disclose

Hiroshi Honda MD, Abstract Co-Author: Nothing to Disclose

Marc van Cauteren, Abstract Co-Author: Employee, Koninklijke Philips Electronics NV

Tomoyuki Okuaki, Abstract Co-Author: Employee, Koninklijke Philips Electronics NV

Shutaro Saiki, Abstract Co-Author: Employee, Koninklijke Philips Electronics NV

et al, Abstract Co-Author: Nothing to Disclose

et al, Abstract Co-Author: Nothing to Disclose

To study age-related changes in microscopic organization of subcortical white matter in individual cerebral cortical regions during postoadolescent periods in men.

Diffusion-weighted images of 36 healthy male subjects (12 to 66 years old) were obtained using a 1.5 T MR scanner (Gyroscan Achieva, Philips Medical Systems) and a CSF-nulled DTI pulse sequence. Fifty contiguous slices (2.5 mm thick) were obtained covering the whole brain. 3D mapping of mean diffusivity (MD) in subcortical white matter was performed using a previously reported method. Using a free software package (Individual Brain Atlases using Statistical Parametric Mapping Software, IABSPM), we obtained mean MD values in subcortical white matter in 80 cerebral cortical regions. To characterize the age-related MD change in each cortical region, a regression analysis was performed applying a quadratic and a linear function at a significance level of p < 0.05 (corrected for multiple comparisons).

Age-related MD changes were modeled by quadratic functions in 23 regions including left precentral and left middle frontal gyri, opercular and triangular portions of left inferior frontal gyrus, opercular portion of left rolandic cortex, bilateral parahippocampal gyri, left calcaline cortex, right lingual gyrus, left superior and inferior occipital gyri, bilateral fusiform gyri, left postcentral gyrus, left inferior parietal gyrus, left supramarginal gyrus, left angular gyrus, left superior temporal gyrus, left middle temporal gyrus, right temporal pole, and bilateral inferior temporal gyri. In these regions, MD continued to decrease until middle age, reaching minimum at around 45 years old, and then increased in older ages. In two cortical regions (left insula and right middle temporal gyrus), MD changes were modeled by linear functions.

Our results revealed non-linear effects of age on MD in subcortical white matter in men. These findings are consistent with continuous progression of myelination after adolescence and subsequent degeneration by aging.

This study provides normative data of white matter maturation which can be used in detecting white matter diseases.

Yoshiura, T, Noguchi, T, Hiwatashi, A, Togao, O, Yamashita, K, Honda, H, van Cauteren, M, Okuaki, T, Saiki, S, et al, , et al, , Non-linear effect of Age on Microscopic Organization of Subcortical White Matter within Individual Cortical Regions Revealed by Diffusion-weighted MRI.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5004436.html