Development of a clinically feasible [¹¹C]PE2I PET method for differential diagnosis of parkinsonism using reduced...

[¹¹C]PE2I is a highly selective dopamine transporter PET ligand. Parametric images based on dynamic [¹¹C]PE2I scans, showing dopamine transporter availability (BP_ND) and relative cerebral blood flow (R₁), can be used in differential diagnosis of parkinsonism. This work aimed to investigate a shortened scan duration and automated generation of parametric images which are two prerequisites for routine clinical application. Twelve subjects with parkinsonism and seventeen healthy controls underwent 80 min dynamic [¹¹C]PE2I PET scans. BP_ND and R₁ images were generated using cerebellum reference region defined on a co-registered MRI, as well as a supervised cluster analysis (SVCA)-based reference. Initial 20, 30 and 40 min of the scans were extracted and images of standardized uptake value ratio (SUVR) and R₁ were computed using MRI- and SVCA-based reference. Correlation was high between striatal 80 min MRI-based BP_ND and 40 min SVCA-based SUVR-1 (R²=0.95). High correlation was also found between R₁ values in striatal and limbic regions (R²≥0.91) whereas correlation was moderate for cortical regions (R²=0.71). The results indicate that dynamic [¹¹C]PE2I scans can be restricted to 40 min and that SVCA can be used for automatic extraction of a reference region. These outcomes will support routine applications of [¹¹C]PE2I PET in clinical settings.