Age-related white matter changes in high b-value q-space diffusion-weighted imaging

Abstract

To assess and compare age-related diffusion changes in the white matter in different cerebral lobes, as quantified by diffusion-weighted imaging (DWI) and high b-value q-space imaging (QSI). Seventy-three cases without neurological symptoms or imaging abnormalities were grouped by age as young (<30 years, n = 20), middle-aged (30-49 years, n = 19), old (50-69 years, n = 18), and very old (> 70 years, n = 16) and imaged by a 1.5-T MR scanner for DWI and QSI. Apparent diffusion coefficient (ADC) and mean displacement (MDP) values were calculated in the white matter of frontal, parietal, and temporal lobes and compared using Dunnett's test, with the young group as a control. MDP values in frontal and parietal lobes were significantly higher in old and very old age groups than in the young, while those in the temporal lobes were significantly higher only in the very old group. ADC values were significantly higher in all three lobes in the very old group. QSI is more sensitive than DWI to age-related myelin loss in white matter.