Abstract
A 63-year-old woman who presented for orofacial dystonia showed cortical ribboning, a typical MRI finding in sporadic Creutzfeldt-Jakob disease (sCJD). However, real-time quaking-induced conversion (RT-QuIC), the most sensitive method for an early diagnosis of sCJD, was negative. She developed sCJD six months later, at which time RT-QuIC became positive. The cerebral blood flow showed a decrease in the cerebral cortex (especially in the supramarginal gyrus) consistent with cortical ribboning, but an increase in the basal ganglia, probably involved in orofacial dystonia. Cortical ribboning on MRI might be a better biomarker than RT-QuIC in the prodromal phase of sCJD.