Alterations of regional cerebral blood flow and oxygen metabolism in Parkinson's disease.

Regional cerebral blood flow (rCBF) and oxygen metabolism (rCMRO2) were determined in six normals, six unilateral Parkinson's disease (PD) patients, and eight bilateral PD patients. In the unilateral patients, rCBF and rCMRO2 in the basal ganglia contralateral to the symptomatic limbs was 13% higher than on the other side (p less than 0.01); in the frontal cortex it was 8% lower than the other side, suggesting abnormal neuronal function in both regions. The bilateral PD patients had a widespread decrease (20%) in rCBF unaccompanied by comparable changes in rCMRO2, suggesting vasoconstriction due to loss of dopaminergic innervation of blood vessels in more advanced PD patients.