CT findings of vulnerable plaque have been regarded as similar to those of the culprit lesion of acute coronary syndrome (ACS). However, this hypothesis may not be accurate if potential changes in the vulnerable plaque during the episode of ACS are considered.

We retrospectively evaluated coronary CT angiography of 25 patients with ACS who had vulnerable (n=10) or culprit plaques (n=15). We analyzed CT features including positive remodeling (PR), low attenuation plaque (LAP), the napkin ring sign (NRS), degree of stenosis (normal, <50%, 50-99%, 100%), and myocardial hypoperfusion in the left ventricle.

There was no difference in the prevalence of PR, NRS, or LAP between the vulnerable and culprit plaques. In contrast, a majority (80%, 8/10) of vulnerable plaques were normal or had <50% stenosis while total occlusion was identified in 46.7% (7/15) patients of culprit plaque (p=0.037). In all patients with occlusion, myocardial hypoperfusion (Fig. 1-3) was demonstrated in the corresponding arterial territory on CT due to thrombosis on coronary angiography.

CT features of vulnerable and culprit plaques differ in cases with thrombotic occlusion reflecting dynamic plaque changes related to the episode of ACS.

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