Amyloid imaging in Alzheimer's disease: comparison of florbetapir and Pittsburgh compound-B positron emission tomography

Abstract

Background: Amyloid imaging provides in vivo detection of the fibrillar amyloid-β (Aβ) plaques of Alzheimer's disease (AD). The positron emission tomography (PET) ligand, Pittsburgh Compound-B (PiB-C11), is the most well studied amyloid imaging agent, but the short half-life of carbon-11 limits its clinical viability. Florbetapir-F18 recently demonstrated in vivo correlation with postmortem Aβ histopathology, but has not been directly compared with PiB-C11.

Methods: Fourteen cognitively normal adults and 12 AD patients underwent PiB-C11 and florbetapir-F18 PET scans within a 28-day period.

Results: Both ligands displayed highly significant group discrimination and correlation of regional uptake.

Conclusion: These data support the hypothesis that florbetapir-F18 provides comparable information with PiB-C11.

Figure

A. Standardized uptake value ratio (SUVR) for both florbetapir-F18 and PiB-C11 in the composite cortical region of interest (ROI) and pons for the cognitively normal adults (grey boxes) and AD patients (white boxes). ‘Boxes’ are drawn between lower and upper quartiles; ‘whiskers’ indicate minimum and maximum values, minus the outliers, indicated by squares; the bold line represents the median and the plus-sign the mean. B. Correlation between florbetapir-F18 and PiB-C11 standardized uptake value ratios (SUVRs) in the composite cortical region of interest (ROI) from 14 cognitively normal (CN; blue) older adults and 12 patients with Alzheimer disease (AD; green). ‘+’ symbols represent cases with AD-range CSF Aβ (< 192 pg/ml) and circles represent normal Aβ (≥ 192 pg/ml). The equation of the best linear fit is given.