Assessment of beta-amyloid in a frontal cortical brain biopsy specimen and by positron emission tomography with carbon 11-labeled Pittsburgh Compound B.

OBJECTIVE: To compare carbon 11-labeled Pittsburgh Compound B ([11C]PiB) positron emission tomography (PET) findings in patients with and without Alzheimer disease lesions in frontal cortical biopsy specimens. DESIGN: Cross-sectional study of [11C]PiB PET findings in patients with or without beta-amyloid (Abeta) aggregates in frontal cortical biopsy specimens. SETTING: Two university hospitals in Finland. Patients Ten patients who had undergone intraventricular pressure monitoring with a frontal cortical biopsy (evaluated for Abeta aggregates and hyperphosphorylated tau) for suspected normal-pressure hydrocephalus. INTERVENTIONS: [11C]PiB PET and evaluation for cognitive impairment using a battery of neuropsychological tests. MAIN OUTCOME MEASURES: Immunohistochemical evaluation for Abeta aggregates and hyperphosphorylated tau in the frontal cortical biopsy specimen and [11C]PiB PET. RESULTS: In patients with Abeta aggregates in the frontal cortical biopsy specimen, PET imaging revealed higher [11C]PiB uptake (P < .05) in the frontal, parietal, and lateral temporal cortices and in the striatum as compared with the patients without frontal Abeta deposits. CONCLUSIONS: Our study supports the use of noninvasive [11C]PiB PET in the assessment of Abeta deposition in the brain. Large prospective studies are required to verify whether [11C]PiB PET will be a diagnostic aid, particularly in early Alzheimer disease.