Vascular uptake on 18 F-sodium fluoride positron emission tomography: precursor of vascular calcification?

Background Microcalcifications cannot be identified with the present resolution of CT; however, 18 F-sodium fluoride ( 18 F-NaF) positron emission tomography (PET) imaging has been proposed for non-invasive identification of microcalcification. The primary objective of this study was to assess whether 18 F-NaF activity can assess the presence and predict the progression of CT detectable vascular calcification. Methods and Results The data of two longitudinal studies in which patients received a 18 F-NaF PET-CT at baseline and after 6 months or 1-year follow-up were used. The target to background ratio (TBR) was measured on PET at baseline and CT calcification was quantified in the femoral arteries at baseline and follow-up. 128 patients were included. A higher TBR at baseline was associated with higher calcification mass at baseline and calcification progression ( β = 1.006 [1.005-1.007] and β = 1.002 [1.002-1.003] in the studies with 6 months and 1-year follow-up, respectively). In areas without calcification at baseline and where calcification developed at follow-up, the TBR was .11–.13 ( P < .001) higher compared to areas where no calcification developed. Conclusion The activity of 18 F-NaF is related to the amount of calcification and calcification progression. In areas where calcification formation occurred, the TBR was slightly but significantly higher.