Gray and White Matter Volume Reductions Associated with Aging in Healthy Korean Adults after Exclusion of White Matter Hyperintensity: A Voxel-Based Morphometric Study

Abstract

Background: Understanding the changes of brain volume due to normal aging in healthy adults may help us better appreciate the age-related changes in the brain associated with neurodegenerative diseases. The objectives of our current study are: 1) to evaluate the volumes of gray matter, white matter and cerebrospinal fluid in healthy adult with exclusion of white matter hyperintensity and 2) to identify their regional changes in which there have been controversies. Methods: We performed a cross-sectional analysis of magnetic resonance images from 108 normal Korean subjects (42-80 yr of age) using voxel-based morphometry. Results: Global volumes of each tissue revealed no change between 5th and 6th decade and their declines afterward. There were negative correlations between gray matter (3.04 cm3/yr) and white matter volume (2.31 cm3/yr) and increasing age, and a positive correlation between CSF volume (5.56 cm3/yr) and increasing age. Gray matter, white matter and CSF volume normalized with total intracranial volume demonstrated changes at 0.21%/yr, 0.16%/yr and 0.36%/yr respectively. Gray matter volume was reduced in the frontal, parietal and temporal lobes with increasing age, but not in the medial temporal lobes or posterior cingulate. White matter losses occurred in the anterior corpus callosum, frontal and other periventricular areas. Conclusions: These findings provide essential information on the rates and regional patterns of age-related changes in brain volume for a healthy Asian population, which can serve as a baseline for comparison with other pathologic conditions.