11C-PiB PET does not detect PrP-amyloid in prion disease patients including variant Creutzfeldt–Jakob disease

Although PrP-amyloid and amyloid β plaques found in Alzheimer's disease (AD) are composed of different peptides, they share common physicochemical properties,1 including a high β-sheet secondary structure and the binding of agents that label amyloid. As amyloid β load can be measured in patients with AD by use of positron emission tomography (PET) and the radiotracer carbon-11-labelled Pittsburgh compound B (11C-PiB), it is possible that 11C-PiB PET could be an in vivo marker of PrP-amyloid. We evaluated whether 11C-PiB PET can reliably demonstrate the presence of abnormal PrP-amyloid deposition in patients who are affected by, or at risk of, human prion disease. This would be of potential clinical importance in early diagnosis, in identifying asymptomatic patients who might benefit from proposed therapeutic interventions, and in monitoring treatment efficacy. Ethical approval for the study was granted by the Research Ethics Committee of the National Hospital for Neurology and Neurosurgery (NHNN) and written informed consent was obtained from subjects. Exclusions included pregnancy, contraindication to MRI, history of cancer in the last 5 years (except skin and prostate) and patients who were unable to give valid informed consent. One patient with variant Creutzfeldt–Jakob disease (vCJD), two symptomatic patients with P102L mutation and two asymptomatic PRNP mutation carriers referred to the National Prion Clinic, NHNN, London, UK, were recruited (four males, age range 25–62 years). Ten control subjects (six males, age range 55–75 years) were also investigated. All subjects underwent an MRI examination using a GE Signa LX 1.5T MRI system at NHNN …