Unilateral Absence of the Basal Ganglia on 123I-Ioflupane DaTScan.

This 33-year-old man presented with hemorrhagic stroke manifesting with left hemiparesis and right ptosis. Angiography revealed no patent carotids. The anterior and middle cerebral arteries were filling collaterally through the posterior vertebrobasilar pathway. The presumptive diagnosis was moyamoya disease. The etiology of the bleeding was right basilar tip aneurysm that subsequently had partial coil placement. Months later, the neck of the aneurysm perforated and second coiling was performed. Later on follow-up, patient developed left hand tremor. A radionuclide DATscan revealed total absence of right-sided basal ganglia activity. A possible etiology was occlusion of the middle cerebral artery's lenticulostriate branches.