DECREASED SINGLE-PHOTON EMISSION COMPUTED TOMOGRAPHIC [(123)]I-BETA-CIT STRIATAL UPTAKE CORRELATES WITH SYMPTOM SEVERITY IN PARKINSONS-DISEASE

Previous studies have utilized single-photon emission computed tomogra phy (SPECT) to demonstrate decreased {I-123}beta-CIT striatal uptake i n idiopathic Parkinson disease (PD) patients. The present study extend s this work by examining SPECT outcome measures in a larger group of P D patients with varying disease severity. Twenty-eight L-dopa-responsi ve PD patients (Hoehn-Yahr stages 1-4) and 27 healthy controls had SPE CT scans at 18 to 24 hours after injection of {I-123}beta-CIT. Specifi c to nondisplaceable striatal uptake ratios (designated V-3 '') were c orrelated with Hoehn-Yahr stage and Unified Parkinson's Disease Rating Scale (UPDRS) subscores. Linear discriminant function analyses utiliz ing striatal uptakes, putamen-to-caudate ratios, and ipsilateral-contr alateral asymmetry indices were performed. Decreased striatal tracer u ptake (V-3 '') was correlated with total UPDRS score for both contrala teral and ipsilateral striatum. Putamen uptake was relatively more red uced than caudate with mean putamen:caudate ratios of 0.50 +/- 0.17 an d 0.82 +/- 0.09 for PD patients and controls, respectively. Ipsilatera l: contralateral asymmetry was significantly greater in PD patients th an controls. Discriminant function analysis utilizing V-3 '' for ipsil ateral and contralateral caudate and putamen correctly classified all 55 cases. These data demonstrate marked differences in {I-123}beta-CIT SPECT measures in healthy controls and PD patients. The significant c orrelation of SPECT measures with motor severity suggests {I-123}beta- CIT may be a useful marker of disease severity in PD.