MRI in corticobasal degeneration.

Corticobasal degeneration is a degenerative disease characterized by asymmetric brain atrophy and clinically by asymmetric onset of an akinetic-rigid syndrome with apraxia, dysarthria and dysphagia. Diagnosis must be confirmed by autopsy. We have investigated the ability of MRI to detect asymmetric atrophy to support the clinical diagnosis and permit differential diagnosis against other degenerative disorders. Ten patients with clinical suspicion of corticobasal degeneration were studied by brain MRI, and the images were reviewed with the side of greater clinical involvement unknown to the reviewer. The original reports of MR scans were also reviewed. MRI demonstrates that cortical atrophy is asymmetric and more marked in the posterior frontal and mainly in the parietal regions on the side contralateral to the clinical symptoms. Asymmetry was rarely detected on the first reading. Our review of MRI findings demonstrates that it is possible to detect asymmetrical parietal atrophy, thus supporting the clinical diagnosis of corticobasal degeneration. It is essential to be aware of the disease and alert for asymmetries in order to discern the more involved side. No abnormalities were detected in the basal ganglia.