Imaging brain amyloid in Alzheimer's disease with Pittsburgh Compound‐B

TLDR

This study reports the first human use of the Pittsburgh Compound‑B PET tracer to image amyloid in 16 mild Alzheimer’s patients and 9 controls. PIB, a novel amyloid‑binding PET tracer, was administered and brain uptake was quantified by PET scanning in the patient and control groups. Compared with controls, AD patients showed markedly increased PIB retention in association cortices—especially frontal, parietal, temporal, occipital, and striatum—while retention was similar in unaffected regions, and higher PIB uptake correlated inversely with cerebral glucose metabolism.

Abstract

This report describes the first human study of a novel amyloid-imaging positron emission tomography (PET) tracer, termed Pittsburgh Compound-B (PIB), in 16 patients with diagnosed mild AD and 9 controls. Compared with controls, AD patients typically showed marked retention of PIB in areas of association cortex known to contain large amounts of amyloid deposits in AD. In the AD patient group, PIB retention was increased most prominently in frontal cortex (1.94-fold, p = 0.0001). Large increases also were observed in parietal (1.71-fold, p = 0.0002), temporal (1.52-fold, p = 0.002), and occipital (1.54-fold, p = 0.002) cortex and the striatum (1.76-fold, p = 0.0001). PIB retention was equivalent in AD patients and controls in areas known to be relatively unaffected by amyloid deposition (such as subcortical white matter, pons, and cerebellum). Studies in three young (21 years) and six older healthy controls (69.5 +/- 11 years) showed low PIB retention in cortical areas and no significant group differences between young and older controls. In cortical areas, PIB retention correlated inversely with cerebral glucose metabolism determined with 18F-fluorodeoxyglucose. This relationship was most robust in the parietal cortex (r = -0.72; p = 0.0001). The results suggest that PET imaging with the novel tracer, PIB, can provide quantitative information on amyloid deposits in living subjects.