Assessment of 18F‐NaF Positron Emission Tomography Imaging for Early Coronary Artery Calcification

Abstract

18F‐NaF uptake has been investigated as an in vivo biomarker of coronary artery calcification (CAC) in humans. CAC increases risk of fatal cardiac events in coronary artery disease (CAD) patients, thus making early diagnosis and clinical intervention extremely important. We assessed 18F‐NaF positron emission tomography (PET) as a diagnostic tool for early CAC in a preclinical swine model of metabolic syndrome (MetS) and CAD by comparing multiple imaging modalities: PET, computed tomography (CT), intravascular ultrasound (IVUS), and histopathology for their sensitivity. MetS Ossabaw swine (N=11) with early‐stage CAD underwent ECG‐gated 18F‐NaF PET/CT scans. Global cardiac and coronary tracking techniques were used to measure 18F‐NaF uptake. MetS swine had almost 2‐fold increased 18F‐NaF uptake in the conduit coronary arteries (p<0.05) and 2.5‐fold increased global molecular calcium score (p<0.05) compared to lean (N=3). IVUS resolved calcification in only 1 MetS pig. All pigs had Agatston CT calcium scores of 0. Histology revealed microcalcifications present in 36% of MetS pigs (NS). This is the first report of 18F‐NaF uptake at an early stage of CAD and microcalcification prior to clinically significant, ossified lesions resolvable by IVUS and CT.