IMAGING OF DOPAMINE TRANSPORTERS WITH IODINE-123-FP-CIT SPECT IN HEALTHY CONTROLS AND PATIENTS WITH PARKINSONS-DISEASE

Several SPECT studies reported decreased striatal I-123-N-omega-fluoro propyl-2 beta-carbomethoxy-3 beta-(4-iodophenyl)nortropane ([I-123]FP- CIT) binding in patients with Parkinson's disease. For application in routine clinical studies, information on the reliability and reproduc ibility of the [I-123]FP-CIT SPECT technique is critical. This study r eports on the reliability and reproducibility of [I-123]FP-CIT SPECT i n healthy control subjects and patients with Parkinson's disease using two different analysis protocols: the conventional region of interest (ROI) protocol and a newly developed, fully automatic, operator-indep endent volume of interest (VOI) protocol. Methods: We performed repeat ed [I-123]FP-CIT SPECT scans in 6 healthy control subjects and 10 pati ents with Parkinson's disease to measure scan-to-scan variations. Scin tigraphic data were analyzed 3 hr after injection of the radiotracer. Results: In controls, the mean test/retest for the ratio of the striat al-to-nonspecific [I-123]FP-CIT uptake were (3.79 +/- 0.67/3.82 +/- 0. 74) and (4.16 +/- 0.70/4.08 +/- 0.97) for the ROI and VOI technique, r espectively. No significant differences were measured between test/ret est studies. The mean test/retest variability for the ROI technique wa s low (7.25%) with excellent reliability (rho = 0.99). In addition, th e mean test/retest variability for the VOI technique was also low (7.4 7%) with very high reliability (rho = 0.95). In Parkinson's disease pa tients, we found mean test/retest for the striatal-to-nonspecific [I-1 23]FP-CIT ratio of (1.78 +/- 0.23/1.79 +/- 0.25) and (1.83 +/- 0.31/1. 85 +/- 0.35) using the ROI and VOI technique, respectively. Also in pa tients, these results did not differ significantly between test/retest studies. The mean test/retest variability for the ROI technique was l ow (7.90%) with excellent reliability (rho = 1.00). In addition, the m ean test/retest variability for the VOI technique was also low (7.36%) with high reliability (rho = 0.96). Conclusion: Reliable and reproduc ible results were obtained with the ROI, as well as the VOI technique, for the analysis of striatal dopamine transporters with [I-123]FP-CIT SPECT in healthy controls and Parkinson's disease patients. The use o f an operator-independent method will be a great advantage in routine clinical studies.