[F]FE-PE2I PET is a feasible alternative to [I]FP-CIT SPECT for dopamine transporter imaging in clinically uncertain parkinsonism.

Background: Dopamine transporter (DAT) imaging of striatum is clinically used in Parkinson's disease (PD) and neurodegenerative parkinsonian syndromes (PS) especially in the early disease stages. The aim of the present study was to evaluate the diagnostic performance of the recently developed tracer for DAT imaging [F]FE-PE2I PET/CT to the reference standard [I]FP-CIT SPECT.

Methods: Ninety-eight unselected patients referred for DAT imaging were included prospectively and consecutively and evaluated with [F]FE-PE2I PET/CT and [I]FP-CIT SPECT on two separate days. PET and SPECT scans were categorized independently by two blinded expert readers as either normal, vascular changes, or mixed. Semiquantitative values were obtained for each modality and compared regarding effect size using Glass' delta.

Results: Fifty-six of the [I]FP-CIT SPECT scans were considered abnormal (52 caused by PS, 4 by infarctions). Using [F]FE-PE2I PET/CT, 95 of the 98 patients were categorized identically to SPECT as PS or non-PS with a sensitivity of 0.94 [0.84-0.99] and a specificity of 1.00 [0.92-1.00]. Inter-reader agreement for [F]FE-PE2I PET with a kappa of 0.97 [0.89-1.00] was comparable to the agreement for [I]FP-CIT SPECT of 0.96 [0.76-1.00]. Semiquantitative values for short 10-min reconstructions of [F]FE-PE2I PET/CT were comparable to longer reconstructions. The effect size for putamen/caudate nucleus ratio was significantly increased using PET compared to SPECT.

Conclusions: The high correspondence of [F]FE-PE2I PET compared to reference standard [I]FP-CIT SPECT establishes [F]FE-PE2I PET as a feasible PET tracer for clinical use with favourable scan logistics.