The Mystery of Spotty Calcification

Spotty calcification has recently been introduced as a marker of plaque vulnerability in patients presenting with acute coronary syndrome undergoing invasive and noninvasive coronary imaging,1 and it has been suggested to be of predictive value for percent atheroma volume with greater progression.2 Several pathological and clinical studies applying computed tomography (CT) and intravascular ultrasound (IVUS) demonstrated that spotty calcification is more frequently observed in lesions with plaque rupture compared with stable plaque.3,4 Recently, optical coherence tomography (OCT) has emerged as the premier intracoronary imaging technology with a higher resolution (10–20 μm) than IVUS (100–200 μm) and also when compared with noninvasive CT and magnetic resonance imaging, both with a lower resolution (1 mm; Table). Indeed, OCT studies provided insights into coronary plaque morphology by the ability to discriminate macrophages, fibrous cap thickness, necrotic core/lipid pool, and calcium.5 However, not all agree that spotty calcification is a marker of plaque vulnerability, because high coronary artery calcium scores (>100 Agatston score) represent a powerful marker of future coronary events.6,7 It is therefore important to distinguish the positive association of overall coronary calcium score with cardiovascular mortality8 in the general population from focal or spotty calcification in selected subgroups presenting with acute myocardial infarction.View this table:Table. Assessment of CalcificationSee Article by Ong et al In this issue of Circulation: Cardiovascular Imaging , Ong et al9 investigated 53 patients presenting with ST-segment–elevation myocardial infarction (STEMI) undergoing invasive diagnostic assessment using OCT from a single center in Japan and compared the findings with 55 patients selected from their international multicenter OCT registry of 613 patients with stable angina pectoris (SAP). Spotty calcification was defined on a frame …