Figure 5.

The association of significant stenosis and high-risk plaque features with the probability of acute coronary syndrome in the Rule Out Myocardial Infarction/Ischemia Using Computer Assisted Tomography II trial. Stenosis ≥50%: severe stenosis of the mid-left anterior descending coronary artery (red arrow). Positive remodelling: non-calcified plaque with positive remodelling in the distal right coronary artery. The two-dotted red lines demonstrate the vessel diameters at the proximal and distal references (both 1.8 mm), and the solid red line demonstrates the maximal vessel diameter in the mid-portion of the plaque (2.7 mm). The remodelling index is 1.5. Low Hounsfield units plaque: partially calcified plaque in the mid-right coronary artery with low <30 Hounsfield unit plaque. The red circles demonstrate the three regions of interest, with mean computed tomography numbers of 22, 19, and 20 Hounsfield units. Napkin-ring sign: napkin-ring sign plaque in the mid-left anterior descending coronary artery. Schematic cross-sectional view of the napkin-ring sign. The red line demonstrates the central low Hounsfield unit area of the plaque adjacent to the lumen (yellow ellipse) surrounded by a peripheral rim of the higher computed tomography attenuation (red arrows). Spotty calcium: partially calcified plaque in the mid-right coronary artery with spotty calcification (diameter <3 mm in all directions; red circles). Reprinted with permission from Puchner et al.⁹⁰