Correlation of fluorine 18-labeled sodium fluoride uptake and arterial calcification on whole-body PET/CT in cancer patients

Abstract

Background 

Fluorine-18-labeled sodium fluoride (¹⁸F-NaF) uptake measured with PET in the vessel walls can indicate active microcalcification, a potential biomarker of higher-risk plaques, which are not indicated by macrocalcification measured with computed tomography (CT). The aim of this study was to determine the extent to which ¹⁸F-NaF uptake is correlated with calcification at arterial plaques in cancer patients undergoing whole-body PET/CT imaging.

Patients and methods 

Image data from 179 patients who underwent ¹⁸F-NaF PET/CT were evaluated retrospectively. Plaques were categorized into four groups by calcium score (CS) on CT: CS₁ (≥1000); CS₂ (400–999); CS₃ (100–399), and CS₄ (<100) and into three groups by ¹⁸F-NaF target-to-background ratio (TBR) on PET: TBR_low (≤1.0), TBR_medium (1.0–1.5), and TBR_high (>1.5). Correlations between ¹⁸F-NaF uptake and CS were evaluated.

Results 

Plaques with ¹⁸F-NaF uptake or arterial calcification were observed in 122 (76%) of the 179 patients. We found a weak but statistically significant positive correlation between CS and ¹⁸F-NaF uptake. The TBR in CS₁ plaques was higher than those in CS₃ and CS₄ plaques, and the TBR in CS₂ plaques was higher than that in CS₃ plaques (P<0.05). Compared with patients whose plaques were with ¹⁸F-NaF uptake (TBR>1.5) or arterial calcification (CS>0), patients without plaques of ¹⁸F-NaF uptake or calcification were significantly younger (P=0.00) or with significantly more women (P=0.02).

Conclusion 

Our finding of a weak but significant positive correlation between ¹⁸F-NaF uptake and arterial calcification suggests that ¹⁸F-NaF PET/CT could provide complementary information of active microcalcification for atherosclerosis evaluation in cancer patients.