<sup>18</sup>F-Sodium Fluoride Positron Emission Tomography/Computed Tomography in Ex Vivo Human Coronary Arteries With Histological Correlation.

Overview

OBJECTIVE: ¹⁸F-sodium fluoride (NaF) position emission tomography (PET) activity correlates with high-risk plaque. We examined the correlation between ¹⁸F-NaF PET activity and extent of calcification (microcalcification and macrocalcification) in coronary arteries. Approach and Results: Eighteen ex vivo human coronary arteries were imaged with ¹⁸F-NaF PET/CT, and target to background ratios were analyzed from 101 plaques. Histopathologic analysis evaluated for microcalcification and macrocalcification, plaque morphology, and inflammation. Plaques with microcalcification demonstrated higher ¹⁸F-NaF PET activity (n=84; mean target to background ratio±SD, 9.0±9.7,) than plaques without microcalcification (n=17, 2.9±3.8; P<0.0001). Higher ¹⁸F-NaF PET activity was associated with advanced plaques characterized by fibroatheroma (n=54, 10.7±10.3) compared with plaques with intimal thickening (n=22, 3.5±3.9) or pathological intimal thickening (n=25, 6.1±8.4; P=0.004). No significant association was found between ¹⁸F-NaF PET activity and inflammation (P=0.08). CONCLUSIONS: In ex vivo human coronary arteries, higher ¹⁸F-NaF PET activity was associated with microcalcification and advanced plaque morphology. Since microcalcification and fibroatheromas are high-risk plaque features, ¹⁸F-NaF PET/CT may improve risk-stratification.