Abstract
BACKGROUND: (18)F-NaF positron emission tomography (PET) targets microcalcifications. We compared in vitro microPET assessed (18)F-NaF uptake between culprit and non-culprit human carotid plaques. Furthermore, we compared (18)F-NaF uptake with calcification visualized on microcomputed tomography (microCT). METHODS: Carotid plaques from stroke patients undergoing surgery were incubated in (18)F-NaF and scanned using a microPET and a microCT scan. The average PET assessed (18)F-NaF uptake was expressed as percentage of the incubation dose per gram (%Inc/g). (18)F-NaF PET volume of interest (VOI) was compared with CT calcification VOI. RESULTS: 23 carotid plaques (17 culprit, 6 non-culprit) were included. The average (18)F-NaF uptake in culprit carotid plaques was comparable with the uptake in non-culprit carotid plaques (median 2.32 %Inc/g [IQR 1.98 to 2.81] vs. median 2.35 %Inc/g [IQR 1.77 to 3.00], P = 0.916). Only a median of 10% (IQR 4 to 25) of CT calcification VOI showed increased (18)F-NaF uptake, while merely a median of 35% (IQR 6 to 42) of (18)F-NaF PET VOI showed calcification on CT. CONCLUSIONS: (18)F-NaF PET represents a different stage in the calcification process than CT. We observed a similar PET assessed (18)F-NaF uptake and pattern in culprit and non-culprit plaques of high-risk patients, indicating that this method may be of more value in early atherosclerotic stenosis development.