Comparison of dual-biomarker PIB-PET and dual-tracer PET in AD diagnosis

To identify the optimal time window for capturing perfusion information from early 11C-PIB imaging frames (perfusion PIB, 11C-pPIB) and to compare the performance of 18F-FDG PET and ''dual biomarker'' 11C-PIB PET [11C-pPIB and amyloid PIB (11C-aPIB)] for classification of AD, MCI and CN subjects. Forty subjects (14 CN, 12 MCI and 14 AD patients) underwent 18F-FDG and 11C-PIB PET studies. Pearson correlation between the 18F-FDG image and sum of early 11C-PIB frames was maximised to identify the optimal time window for 11C-pPIB. The classification power of imaging parameters was evaluated with a leave-one-out validation. A 7-min time window yielded the highest correlation between 18F-FDG and 11C-pPIB. 11C-pPIB and 18F-FDG images shared a similar radioactive distribution pattern. 18F-FDG performed better than 11C-pPIB for the classification of both AD vs. CN and MCI vs. CN. 11C-pPIB + 11C-aPIB and 18F-FDG + 11C-aPIB yielded the highest classification accuracy for the classification of AD vs. CN, and 18F-FDG + 11C-aPIB had the best classification performance for the classification of MCI vs. CN. C-pPIB could serve as a useful biomarker of rCBF for measuring neural activity and improve the diagnostic power of PET for AD in conjunction with 11C-aPIB. 18F-FDG and 11C-PIB dual-tracer PET examination could better detect MCI. (orig.)