Longitudinal changes in 18F-THK5351 positron emission tomography in corticobasal syndrome

Background and purpose Corticobasal syndrome (CBS) is pathologically characterized by tau deposits in neuronal and glial cells and by reactive astrogliosis. In several neurodegenerative disorders, F-18-THK5351 has been observed to bind to reactive astrocytes expressing monoamine oxidase B. In this study, the aim was to investigate the progression of disease-related pathology in the brains of patients with CBS using positron emission tomography with F-18-THK5351. Methods Baseline and 1-year follow-up imaging were acquired using magnetic resonance imaging and positron emission tomography with F-18-THK5351 in 10 subjects: five patients with CBS and five age-matched normal controls (NCs). Results The 1-year follow-up scan images revealed that F-18-THK5351 retention had significantly increased in the superior parietal gyrus of the patients with CBS compared with the NCs. The median increases in F-18-THK5351 accumulation in the patients with CBS were 6.53% in the superior parietal gyrus, 4.34% in the precentral gyrus and 4.33% in the postcentral gyrus. In contrast, there was no significant increase in the regional F-18-THK5351 retention in the NCs. Conclusions Longitudinal increases in F-18-THK5351 binding can be detected over a short interval in the cortical sites of patients with CBS. A monoamine oxidase B binding radiotracer could be useful in monitoring the progression of astrogliosis in CBS.