Dopamine transporter SPECT imaging in Parkinson's disease and atypical Parkinsonism: a study of 137 patients.

Background: Differential diagnosis between Parkinson's disease (PD) and multiple system atrophy-parkinsonian type (MSA-P), corticobasal degeneration (CBD), and progressive supranuclear palsy (PSP), collectively termed atypical Parkinsonism (AP), is challenging. Dopamine transporter density imaging with Ioflupane I123 (DaTscan) is a marker of presynaptic nigrostriatal dysfunction. The primary aim of this study was to investigate the utility of DaTscan in the differential diagnosis of MSA-P, CBD, and PSP.

Methods: Patients examined at Eginition Hospital (2011-2021), with available DaTscan data and a diagnosis of probable AP, clinically established PD, as well as a neurological control (NC) group were included. Mean binding specific index (BSI), BSI of the most affected side, asymmetry index, laterality, and caudate/putamen ratio were recorded. Analyses were performed by Kruskal-Wallis and ANCOVA.

Results: 137 patients were included (CBD: [Formula: see text]; MSA-P: [Formula: see text]; PSP: [Formula: see text]; PD: [Formula: see text]; NC: [Formula: see text]). There were significant differences when comparing CBS, PSP, and NC vs. all other groups combined. Pairwise between-group comparisons revealed significant differences between PSP and CBD (mean striatum BSI>1.95; sensitivity 74.1%; specificity 85.0%), CBD and MSA-P (mean striatum BSI>2.04; sensitivity 70.4%; specificity 86.7%), and CBD and PD (mean striatum BSI>2.11; sensitivity 66.7%; specificity 100.0%). There were no differences between PSP, MSA-P, and PD. PSP, MSA-P, and PD differed from NC subjects, with 100% specificity and high sensitivity. Differentiation of NC from CBD was suboptimal.

Conclusions: CBD patients exhibit relatively mild DaTscan abnormalities. DaTscan may assist in the differentiation of CBD from PSP. DaTscan does not differentiate among PD, MSA-P, and PSP.