18F-sodium fluoride positron emission tomography for molecular imaging of coronary atherosclerosis based on computed tomography analysis.

BACKGROUND AND AIMS: We aimed at evaluating the relation of 18F-sodium fluoride (18F-NaF) uptake on positron emission tomography (PET) to coronary atherosclerosis detected and assessed by computed tomography (CT).

METHODS: Thirty-two patients with one or more coronary atherosclerotic lesions detected on cardiac CT underwent 18F-NaF PET/CT. Each coronary atherosclerotic lesion was evaluated on CT angiography for plaque types (calcified plaque [CP], non-calcified plaque [NCP], partially calcified plaque [PCP]), and the presence of CT-based high-risk features (minimum CT density <30 Hounsfield units and vascular remodeling index >1.1). Focal 18F-NaF uptake of each lesion was quantified using maximum tissue-to-background ratio (TBRmax).

RESULTS: A total of 111 lesions were studied. In a patient-based analysis, logarithmically transformed coronary calcium score correlated positively with maximum TBRmax per patient, and 15 patients with myocardial infarction or unstable angina history showed a higher maximum TBRmax per patient than those without (1.36 ± 0.15 versus 1.15 ± 0.15, p = 0.0006). In a lesion-based analysis, PCP showed a higher TBRmax than CP and NCP (1.17 ± 0.19 versus 1.00 ± 0.24 and 0.92 ± 0.18, respectively, p < 0.0001), and the lesions with high-risk features had a higher TBRmax than those without (1.20 ± 0.21 versus 1.02 ± 0.20, p = 0.0011).

CONCLUSIONS: Coronary arterial 18F-NaF uptake is related to total plaque burden, coronary event history, and specific features of coronary atherosclerosis based on CT analysis. 18F-NaF PET/CT, in combination with cardiac CT, may provide a new molecular imaging approach to identify high-risk patients and coronary atherosclerotic lesions.