Volumetric brain changes in thalamus, corpus callosum and medial temporal structures: mild Alzheimer's disease compared with amnestic mild cognitive impairment.

BACKGROUND: It is widely known that atrophy of medial temporal structures is present in the mild stage of Alzheimer's disease (AD) and amnestic mild cognitive impairment (aMCI). However, structures such as the thalamus and corpus callosum are much less studied. METHODS: We compared the volumes of the entorhinal cortex, hippocampus, thalamus and the corpus callosum in 14 controls, 14 patients with mild AD and 15 with aMCI and correlated these volumes with neuropsychological data. MRI was obtained at 2 T followed by manual segmentation. RESULTS: We found atrophy in hippocampi and thalami of MCI patients compared to controls, and in the bilateral entorhinal cortex of aMCI compared to AD patients. All the structures showed atrophy in AD patients compared to controls, including the corpus callosum. CONCLUSIONS: Our study confirms that thalamic areas are atrophied in aMCI, and the corpus callosum might represent a good structural marker for mild AD. Those areas were associated with cognitive functions already described in the literature.