Figure 1. JC Virus Granule Cell Neuronopathy (JCV GCN).
MRI demonstrates progressive cerebellar atrophy without intra-parenchymal lesions. (A) Pre-contrast T1 sagittal image illustrating the size of the cerebellum at symptoms onset. (B) Pre-contrast T1 sagittal image done 4 months later and a week after positive CSF JC Virus PCR shows marked cerebellar atrophy (arrow).