Cortical [F-18]PI-2620 Binding Differentiates Corticobasal Syndrome Subtypes

Background Corticobasal syndrome is associated with cerebral protein aggregates composed of 4-repeat (similar to 50% of cases) or mixed 3-repeat/4-repeat tau isoforms (similar to 25% of cases) or nontauopathies (similar to 25% of cases). Objectives The aim of this single-center study was to investigate the diagnostic value of the tau PET-ligand [F-18]PI-2620 in patients with corticobasal syndrome. Methods Forty-five patients (71.5 +/- 7.6 years) with corticobasal syndrome and 14 age-matched healthy controls underwent [F-18]PI-2620-PET. Beta-amyloid status was determined by cerebral beta-amyloid PET and/or CSF analysis. Subcortical and cortical [F-18]PI-2620 binding was quantitatively and visually compared between beta-amyloid-positive and -negative patients and controls. Regional [F-18]PI-2620 binding was correlated with clinical and demographic data. Results Twenty-four percent (11 of 45) were beta-amyloid-positive. Significantly elevated [F-18]PI-2620 distribution volume ratios were observed in both beta-amyloid-positive and beta-amyloid-negative patients versus controls in the dorsolateral prefrontal cortex and basal ganglia. Cortical [F-18]PI-2620 PET positivity was distinctly higher in beta-amyloid-positive compared with beta-amyloid-negative patients with pronounced involvement of the dorsolateral prefrontal cortex. Semiquantitative analysis of [F-18]PI-2620 PET revealed a sensitivity of 91% for beta-amyloid-positive and of 65% for beta-amyloid-negative cases, which is in excellent agreement with prior clinicopathological data. Regardless of beta-amyloid status, hemispheric lateralization of [F-18]PI-2620 signal reflected contralateral predominance of clinical disease severity. Conclusions Our data indicate a value of [F-18]PI-2620 for evaluating corticobasal syndrome, providing quantitatively and regionally distinct signals in beta-amyloid-positive as well as beta-amyloid-negative corticobasal syndrome. In corticobasal syndrome, [F-18]PI-2620 may potentially serve for a differential diagnosis and for monitoring disease progression. (c) 2021 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Societ