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.
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: TBRlow (≤1.0), TBRmedium (1.0–1.5), and TBRhigh (>1.5). Correlations between 18F-NaF uptake and CS were evaluated.
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).
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.
Departments of aNuclear Medicine
cImaging Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
dDepartment of Nuclear Medicine, Tianjin Medical University Cancer Institute and Hospital, Tianjin, China
Correspondence to Tinsu Pan, PhD, Unit 1352, Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd, Houston, TX 70030-4009, USA Tel: +1 713 563 2714; fax: +1 713 563 8842; e-mail: email@example.com
Received October 23, 2018
Accepted January 14, 2019