SPP1 and myocardial infarction: In addition to existing evidence linking OPN/microcalcification to 18F-sodium fluoride uptake in coronary arteries [24], OPN has been gaining more interest as a biomarker for increased risk of myocardial infarction (MI) in asymptomatic patients, as well as its role as a predictor of adverse outcomes in patients with carotid stenosis [38,39,40,41,42].