CLINICAL CORRELATES OF [F-18]FLUORODOPA UPTAKE IN 5 GRAFTED PARKINSONIAN-PATIENTS

To assess the efficacy of fetal mesencephalic grafts in Parkinson's di sease, it is important to know if the grafted cells survive and are fu nctional. Positron emission tomography (PET) and [F-18}fluorodopa ({F- 18}dopa) have been used to demonstrate the survival of the grafted cel ls, but the relationship of {F-18]dopa uptake changes in the grafted s triatum to motor function remains unclear. We investigated this questi on with 16 serial PET scans in 5 severe parkinsonian patients unilater ally grafted in whom we found a significant and progressive increase o f the {F-18}dopa uptake in the grafted putamen. The number of patients was too small to assess the sensitivity of {F-18}dopa PET scans in in dividual patients. Yet, by analyzing the 16 serial PET scans we found a correlation between the {F-18}dopa uptake (K-i) in the grafted putam en and the percentage of daily time spent ''on,'' suggesting that Ki c hanges have a functional meaning. In addition, the K-i values were cor related with the contralateral finger dexterity to the same extent in both the grafted and nongrafted putamen. These results indicate that { F-18}dopa uptake reflects the motor function of the opposite side of t he body, similarly in the grafted and ungrafted putamen, at least in t erms of these tasks. Finally, extrapolating from these correlations of fers the suggestion that clinical optimal results of the graft could b e achieved if the graft brings the K-i values in the putamen to about two standard deviations of mean control values.