The preliminary diffuse tensor MR imaging study of correlation of white matter anisotropy with age in normal adults

Objective To explore the evaluation of FA(fractional anisotropy) in assessing the age-related physiologic changes of white matter in normal adults by use of diffuse tensor MR imaging(DTI) Methods Thirty healthy subjects(20-30 y, 15 subjects ;60-83 y,15 subjects) underwent conventional MRI and diffusion-tensor MR imaging. DTI was performed using single shot SE-EPI sequence. The b value was 1000 s· mm~(- 2). The diffusion was measured along 13 directions. FA was measured in genu and splenium of corpus callosum, the knee and posterior limb of internal capsule, optic radiations, frontal white matter, thalamus respectively. Statistical analysis was performed. Results The FA values of young group in genu and splenium of corpus callosum, the knee and posterior limb of internal capsule, optic radiations, frontal white matter, thalamus were(0.70 ± 0.05),(0.70±0.05),(0.63±0.04), (0.63±0.02),(0.53±0.05),(0.43±0.06), (0.27±0.02)respectively. The FA values of older group in genu and splenium of corpus callosum, the knee and posterior limb of internal capsule, optic radiations, frontal white matter, thalamus were(0.62±0.09),(0.66±0.07),(0.57±0.07),(0.61±0.04),(0.38±0.06),(0.38±0.07),(0.27±0.03). A significant FA declines of older group in genu and splenium of corpus callosum , the knee of internal capsule, optic radiations, frontal white matter were found (P0.05). The FA Value in posterior limb of internal capsule of older group was lower. But no significant difference was observed between two groups(P0.05). There was no significant difference in FA between the left and right hemisphere(P0.05). Conclusions DTI is valuable in assessing the directionality and density of white matter and can reflect the age-related physiological changes of white matter in vivo non- invasively.