PET before and after surgery for tumor-induced parkinsonism.

We studied a patient with left frontal meningioma and right-sided parkinsonism that resolved completely after operation. PET scans were performed before and after operation to measure regional cerebral blood flow, oxygen extraction ratio, oxygen utilization, and blood volume. A specific pattern of severe functional changes returned to normal postoperatively. The data suggest increased local tissue pressure due to edema, causing a functional disorder in the left basal ganglia that gave rise to reversible contralateral parkinsonism.