Fig. 1.

Focal T2*w hypointensities in the basal ganglia of a typical subject. The perimeters of the T2*w hypointensity masks from the rater are indicated by red lines on top of (A) T2*w and (B) co-registered T1w axial slices. This particular subject just exhibits multifocal T2*w hypointensities in the globus pallidus. In more severe cases, T2*w hypointensities are also found in the internal capsule, putamen and caudate. Arrows indicate arterial structures, which mimic T2*w hypointensities on T2*w MRI. However, these features have a branch like appearance and are generally hypointense on T1w MRI.