DIFFERENTIAL-DIAGNOSIS IN PATIENTS WITH EXTRAPYRAMIDAL MOVEMENT-DISORDERS - I-123 IBZM-SPECT VS APOMORPHINE-TEST

The aim of our study was to compare the striatal dopamine D2-receptor density as measured by I-123-IBZM-SPECT with the results of the apomorphine-test. 30 patients were studied; 21 with idiopathic Parkinson's disease (IPD), 9 with Parkinson plus syndromes (PPS). Patients with IPD showed a significantly higher striatal IBZM binding as compared to patients with PPS (p = 0.006). A good correlation between IBZM binding and outcome of the apomorphine-test was found (p = 0.006). Low striatal IBZM binding indicates reduced dopamine D2-receptor density. This compromises successful dopaminergic medical therapy and is indicative of non-IPD disease. I-123-IBZM-SPECT could be diagnostic aid in the work-up of patients with extrapyramidal movement disorders. The response to dopaminergic drug treatment might be precluded by IBZM-SPECT in patients with Parkinsonian syndromes.