Head-to-head comparison of (11)C-PiB and (18)F-FC119S for Aβ imaging in healthy subjects, mild cognitive impairment patients, and Alzheimer's disease patients

As a new beta amyloid (Aβ) positron emission tomography (PET) tracer, (18)F-FC119S has shown higher cortical uptake in patients with Alzheimer's disease (AD) than that in healthy control subjects without adverse effects in a previous preliminary study. The aim of this study was to compare (18)F-FC119S PET and (11)C-PiB PET in healthy control (HC) subjects, mild cognitive impairment (MCI) patients, and AD patients. A total of 48 subjects, including 28 HC subjects, 10 MCI patients, and 10 AD patients, underwent static (18)F-FC119S PET (30 minutes after intravenous [i.v.] injection) and (11)C-PiB PET (40 minutes after i.v. injection) on the same day. Both PET images were visually and quantitatively assessed. Standardized uptake value ratios (SUVRs) were calculated for each brain region using the cerebellar cortex as a reference region. None (0%) of the 28 HC subjects and 4 (40%) of 10 MCI patients had positive scans on both PET images. Of the 10 AD patients, 7 (70%) had positive scans on (11)C-PiB PET while 6 (60%) had positive scans on (18)F-FC119S PET. Overall, 47 (98%) of 48 participants showed identical results based on visual analysis. Cortical SUVR of (18)F-FC119S was higher in AD patients (1.38 ± 0.16), followed by that in MCI patients (1.24 ± 0.10) and in HC subjects (1.14 ± 0.05). Compared with (11)C-PiB PET, (18)F-FC119S PET yielded a higher effect size (d = 2.02 vs. 1.67) in AD patients and a slightly lower effect size (d = 1.26 vs. 1.38) in MCI patients. In HC subjects, the nonspecific binding of (18)F-FC119S to white matter (with the frontal cortex-to-white matter SUV ratio of 0.76) was slightly lower than that of (11)C-PiB (ratio of 0.73). There was a significant linear correlation (slope = 0.41, r = 0.78, P < 0.001) between (11)C-PiB and (18)F-FC119S cortical SUVR. We could safely obtain images similar to (11)C-PiB PET imaging Aβ in the brain using (18)F-FC119S PET. Therefore, (18)F-FC119S might be suitable for imaging Aβ deposition.