The Added Diagnostic Value of ¹⁸ F-FDG PET/CT in Suspected CreutzfeldtJakob Disease: A Retrospective Case Series

The diagnosis of Creutzfeldt–Jakob disease (CJD) relies on a constellation of clinical signs and ancillary tests, with MRI serving as the imaging cornerstone. However, Magnetic resonance imaging (MRI) can be inconclusive or miss early pathological changes. This retrospective case series illustrates the complementary diagnostic value of 18 F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography ( 18 F-FDG PET/CT) in four patients with suspected CJD. In all cases, 18 F-FDG PET/CT not only confirmed hypometabolism corresponding to regions of MRI diffusion restriction but also revealed a more extensive topography of neuronal dysfunction by identifying metabolic deficits in structurally normal areas. This consistent PET-MRI discordance highlights PET's sensitivity to detect early synaptic dysfunction. We conclude that 18 F-FDG PET/CT is a powerful adjunct to MRI, increasing diagnostic confidence by providing crucial functional data, aiding in the differential diagnosis of rapidly progressive dementia, and offering a more comprehensive assessment of disease burden, particularly in diagnostically challenging presentations.