Comparison of two methods for the analysis of [18F]6-fluoro-L-m-tyrosine PET data

PET and [F-18]fluoro-L-m-tyrosine (FMT) have been used to quantify presynaptic striatal dopamine (DA) function in Parkinson disease (PD) and in primate models of PD. While dynamic imaging and a metabolite-corrected blood input function can be used to determine striatal FMT uptake rate constants (K-i), a simpler analytic approach using shorter imaging times is desirable for clinical studies. We compared the utility of using striatal K-i values versus striatal count ratios in two groups of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated monkeys. Striatal DA content was also measured in one of the groups to evaluate the relationship between the PET measures and an independent measure of striatal dopamine. Striatal K-i values were significantly correlated with striatal count ratios using the cerebellum as the denominator. Both K-i values and ratios were also correlated with striatal DA content. In addition, putamen-cerebellum ratios and putamen K-i values showed similar separation between baseline and post-MPTP values. These findings suggest that a simple ratio approach to analyzing FMT PET data may be a useful alternative to a kinetic approach especially for clinical applications. (C) 2004 Elsevier Inc. All rights reserved.