Vulnerable plaque on IVUS. An intravascular ultrasound (IVUS) cross-section of the coronary artery demonstrating the vulnerable plaque features that can be visualized with IVUS. The plaque demonstrates a plaque burden that is greater than 70%, measured as the external elastic membrane (EEM) area (green line) minus the luminal area (red line), divided by the EEM. The plaque appears echolucent, indicating the presence of a large lipid core and deep echo attenuation is visible. Furthermore, microcalcifications and outward vessel remodeling can be observed.