The Napkin Ring Sign – the Story Behind Invasive Coronary Angiography

DOI: 10.2478/jim-2021-0006


Coronary artery disease (CAD) represents one of the leading cause of morbidity and mortality across Europe. Most of the patients do not experience any warning sign before the coronary event develop, therefore screening this group of patients is essential to prevent major cardiac events. Coronary computed tomography angiography (CCTA) offers a noninvasive approach of the coronary arteries, providing information not only on the presence and the severity of the coronary stenosis, but also being able to characterize the coronary wall structure. CCTA allows complex evaluation of the extension of CAD, and by assessing the atherosclerotic plaque structure can identify its vulnerability degree. The napkin-ring sign (NRS) represents a ringlike attenuation of the non-calcified portion of the coronary lesion and has a high specificity (96–100%) for the identification of thin cap fibroatheroma (TCFA) or culprit lesion in acute coronary syndromes (ACS). It is also an independent predictor for ACS events and the strongest predictor for future ACS. Modern CCTA can provide submillimeter isotropic spatial resolution. Thus, the CT attenuation based tissue interpretation enables the assessment of total coronary plaque burden, and individual plaque components, with a similar accuracy as IVUS based investigations. This review aims to present the important role of CCTA, as a potent screening tool for patients with CAD, and the current evidences in the detection and quantification of vulnerable plaques.