Predictors of 18F-sodium fluoride uptake in patients with stable coronary artery disease and adverse plaque features on computed tomography angiography

Abstract

Abstract Aims In patients with stable coronary artery disease (CAD) and high-risk plaques (HRPs) on coronary computed tomography angiography (CTA), we sought to define qualitative and quantitative CTA predictors of abnormal coronary 18F-sodium fluoride uptake (18F-NaF) by positron emission tomography (PET). Methods and results Patients undergoing coronary CTA were screened for HRP. Those who presented with ≥3 CTA adverse plaque features (APFs) including positive remodelling; low attenuation plaque (LAP, <30 HU), spotty calcification; obstructive coronary stenosis ≥50%; plaque volume >100 mm3 were recruited for 18F-NaF PET. In lesions with stenosis ≥25%, quantitative plaque analysis and maximum 18F-NaF target to background ratios (TBRs) were measured. Of 55 patients, 35 (64%) manifested coronary 18F-NaF uptake. Of 68 high-risk lesions 49 (70%) had increased PET tracer activity. Of the APFs, LAP had the highest sensitivity (39.4%) and specificity (98.3%) for predicting 18F-NaF uptake. TBR values were higher in lesions with LAP compared to those without [1.6 (1.3–1.8) vs. 1.1 (1.0–1.3), P = 0.01]. On adjusted multivariable regression analysis, LAP (both qualitative and quantitative) was independently associated with plaque TBR [LAP qualitative: β = 0.47, 95% confidence interval (CI) 0.30–0.65; P < 0.001] and (LAP volume: β = 0.20 per 10 mm3, 95% CI 0.13–0.27; P < 0.001). Conclusion In stable CAD patients with HRP, LAP is predictive of 18F-NaF coronary uptake, but 18F-NaF is often seen in the absence of LAP. If 18F-NaF uptake is shown to be associated with adverse outcomes and becomes clinically used, the presence of LAP may define patients who would not benefit from the added testing.