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

ABSTRACT

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