[Cerebral perfusion and oxygen metabolism in Parkinson's disease: positron emission tomographic study using...

In many previous studies, positron emission tomography (PET) has been used to evaluate cerebral perfusion and oxygen metabolism in Parkinson's disease. In this article, these previous reports are reviewed together with our recent findings. Hypoperfusion and hypometabolism in parkinsonian brains reported previously seemed to be derived chiefly from psychiatric manifestations, including intellectual decline and depression. In our study on 34 patients with asymmetric symptoms, the blood flow and oxygen metabolism were significantly higher in the caudate head and putamen, contralateral to the predominant patient's symptoms, than in the opposite nuclei. The asymmetry in the perfusion and metabolism is clearer in the early stage of the disease or in patients without DOPA therapy. These findings suggest that the striatal dysfunction is caused by uninhibited activities, supersensitivities, or compensatory hyperactivities of the striatum.