Corpus callosum in Alzheimer's disease and vascular dementia a quantitative magnetic resonance study

We investigated atrophic alterations in different regions of the corpus cal losum in Alzheimer's disease (AD) and vascular dementia (VD) with respect t o clinical changes. 32 patients with AD (NINCDS-ADRDA criteria), 17 patient s with VD (NINDS-AIREN criteria) and 13 healthy control subjects were inclu ded. 3-D MRI sequences were acquired using a 1.5T MRI scanner. The size of the corpus callosum and its subdivisions was sampled on 5 mid-saggital slic es using a personal computer-based software. Total callosal size was signif icantly reduced in AD but not in VD. Furthermore, the most rostral parts of the corpus callosum were significantly smaller in AD when compared to cont rols. Again, these changes were not found in patients with VD. Severity of dementia was significantly correlated with the size of the midbody of the c orpus callosum in AD. Callosal atrophy in AD may reflect the severity and p attern of cortical neuronal damage occurring mostly in the inferior frontal , anterior parietal and midtemporal regions. Correlations between regional callosal atrophy and severity of dementia indicate that interhemispheric co rtico-cortical disconnections may contribute to the dementia syndrome.