Voxel-based morphometry detects cortical atrophy in the Parkinson variant of multiple system atrophy

To determine magnetic resonance imaging (MRI) patterns of brain atrophy in parkinsonian syndromes, we applied voxel-based morphometry (VBM) to segmented gray matter, white matter, and cerebrospinal fluid compartments of T(1)-weighted brain volumes of 12 patients with probable multiple system atrophy-parkinson variant (MSA-P) and 12 Parkinson's disease patients, comparing them with 12 normal controls matched for age. In comparison to controls, a cortical atrophy pattern was observed in MSA-P patients with significant clusters of volume loss in primary sensorimotor cortices bilateral, supplementary motor areas bilateral, right premotor cortex, prefrontal cortex bilateral (middle frontal gyri) and insular cortices bilateral; subcortical atrophy occurred bilaterally in caudate nuclei and putamen as well as in the midbrain. Furthermore, an enlargement of the cerebrospinal fluid compartment was found in the lateral ventricles, third ventricle, perimesencephalic and cerebellomedullar cavities. In PD patients, significant atrophy only occurred in left caudate head with enlargement of left lateral ventricle. Comparing MSA-P to PD patients, MSA-P showed a similar cortical pattern of atrophy as compared to controls. We conclude that VBM reveals selective cortical atrophy in patients with MSA-P affecting primary and higher order motor areas as well as prefrontal and insular cortices. Further studies are required to determine clinical and/or subclinical correlates of cortical atrophy in MSA-P.