Parkinson's disease and local atrophy in subcortical nuclei: insight from shape analysis.

Parkinson's disease (PD) is characterized by loss of dopaminergic neurons in the substantia nigra pars compacta, inducing dopaminergic depletion in the striatum. Recently, subcortical nuclei shape analysis based on T1 imaging has been used in PD pathology. The present study aimed to test the hypothesis that changes in local volume detectable with T1-weighted imaging are concomitant with PD and may be used as biomarkers. We compared 21 PD patients and 20 control subjects using gray matter density and subcortical nuclei volume and shape. We also tested correlations between these parameters and clinical scales. A linear discriminant analyses was carried out using global volume and local atrophy. The differences revealed between the 2 groups were volume differences in the putamen and shape differences in the putamen and the caudate nucleus. A correlation was found between shape and motor symptoms. The discriminant analysis performed using local atrophy values led to the best classification. Our results show that shape analysis contributes valuable information to investigations concerning PD patients and helps to discriminate these patients from control subjects.