Clinical Relevance of ¹⁸F-Sodium Fluoride Positron-Emission Tomography in Noninvasive Identification of High-Risk Plaque in Patients With Coronary Artery Disease

Background: ¹⁸F-sodium fluoride (¹⁸F-NaF) positron-emission tomography has been introduced as a potential noninvasive imaging tool to identify plaques with high-risk characteristics in patients with coronary artery disease. We sought to evaluate the clinical relevance of ¹⁸F-NaF uptake using optical coherence tomography (OCT), intravascular ultrasound (IVUS), and coronary computed tomography angiography in patients with coronary artery disease.

Methods and results: The target population consisted of 51 prospectively enrolled patients (93 stenoses) who underwent ¹⁸F-NaF positron-emission tomography before invasive coronary angiography. ¹⁸F-NaF uptake was compared with IVUS- and OCT-derived plaque characteristics. In the coronary computed tomography angiography subgroup (46 lesions), qualitative lesion characteristics were compared between ¹⁸F-NaF-positive and ¹⁸F-NaF-negative plaques using adverse plaque characteristics. The plaques with ¹⁸F-NaF uptake showed significantly higher plaque burden, more frequent posterior attenuation and positive remodeling in IVUS, and significantly higher maximum lipid arc and more frequent microvessels in OCT (all P<0.05). There were no differences in minimum lumen area and area of calcium between ¹⁸F-NaF-positive and ¹⁸F-NaF-negative lesions. Among 51 lesions with ¹⁸F-NaF-positive uptake, 48 lesions (94.1%) had at least one of high-risk characteristics. The ¹⁸F-NaF tissue-to-background ratio in plaques with high-risk characteristics was significantly higher than in those without (1.09 [95% confidence interval, 0.85-1.34] versus 0.62 [95% confidence interval, 0.42-0.82], P<0.001 for IVUS definition; 0.76 [95% confidence interval, 0.54-0.98] versus 0.42 [95% confidence interval, 0.21-0.62], P=0.014 for OCT definition). Among the 15 lesions that met both IVUS- and OCT-defined criteria for high-risk plaque, 14 (93.3%) showed ¹⁸F-NaF-positive uptake. There was no difference in the prevalence of plaques with any adverse plaque characteristics between ¹⁸F-NaF-positive and ¹⁸F-NaF-negative plaques in the coronary computed tomography angiography subgroup (85.2% versus 78.9%; P=0.583).

Conclusions: This study's results suggest that ¹⁸F-NaF positron-emission tomography can be a useful noninvasive diagnostic tool to identify and localize plaque with high-risk characteristics.

Clinical trial registration: URL: http://www.clinicaltrials.gov. Unique identifier: NCT02388412.