SPECT-Evaluation of the Monoamine Uptake Site Ligand [ ¹²³ I](1R)- 2-Beta-Carbomethoxy-3-Beta-(4-iodophenyl)-Tropane ([ ¹²³ I]Beta- CIT) in Untreated Patients with Suspicion of Parkinson Disease

Background For a few years, data on SPECT-imaging of dopamine transporters with the cocaine derivate [ 123 I](1R)-2- beta-carbomethoxy-3-beta-(4-iodophenyl)-tropane ([ 123 I]beta-CIT) have been reported mostly in healthy subjects or animals. This study reflects our preliminary results with SPECT-imaging of dopamine transporters using the cocaine analogue 123 I-β-CIT in patients with untreated (de novo) parkinsonism. Methods In 33 patients with clinical suspicion of Parkinson disease and 5 healthy controls, SPECT-imaging of dopamine transporters was performed 1, 4, and 24 hours after injection of 180 MBq of 123 I-β-CIT, which was generated by iododestannylation. None of the patients or controls had been treated before with neuroleptical drugs or any other pharmaceuticals with known binding to the dopamine transporters. Clinical symptoms were staged by the scales of Hoehn-Yahr (HYS), Unified Parkinson Disease Rating Scale (UPDRS), and the self-rating scale of Beck depression inventory (BDI). For evaluation, striatal/cerebellar ratios were calculated to every time point. Results Significant correlations of 123 I-β-CIT uptake could be stated compared to UPDRS, HYS, and BDI values (Spearman correlation, p < 0.05). The symptoms of rigor and akinesia showed a significant correlation with the β-CIT uptake, whereas the symptom of tremor failed, which may be caused by the location of tremor symptoms out of the striatum. Comparing the controls, a significant (p < 0.01) decrease of tracer uptake in parkinsonian patients is stated on the images at 24 hours p.i. In our patients, tracer uptake does not depend significantly on duration of disease and age. Conclusion 123 I-β-CIT seems to be a promising tool in imaging of untreated parkinsonian patients.