DIFFERENTIAL-DIAGNOSIS OF PARKINSONISM WITH [F-18] FLUORODEOXYGLUCOSEAND PET

The clinical differentiation between typical idiopathic Parkinson's di sease (IPD) and atypical parkinsonian dis orders (APD) is complicated by the presence of signs and symptoms common to both forms of parkinso nism, Metabolic brain imaging with [F-18]fluoradeoxgglucose (FDG) and positron emission tomography (PET) may be a useful adjunct in differen tiating APD from IPD. To explore this possibility. we studied 48 parki nsonian patients suspected as having possible APD because of a deterio rating response to dopaminergic treatment, the development of autonomi c dysfunction, or both, A group of 56 patients with likely LPI) served as control subjects. We used quantitative FDG/PET to measure regional rates of cerebral glucose use in IPD and APD patients, We used discri minant analysis to categorize IPD and APD patients based on their regi onal metabolic data. We found that a linear combination of caudate, le ntiform, and thalamic values accurately discriminated APD from TPD pat ients (p < 0.0001), Significant metabolic abnormalities were present i n the striatum and the thalamus of 36 of 48 (75%) APD patients. Our fi ndings show that measurements of regional glucose metabolism can be us ed to discriminate patients with suspected APD from their counterparts with classic IPD. FDG/PET may be a useful adjunct to the clinical exa mination in the differential diagnosis of parkinsonism.