Background Disrupted plaques are the major cause of acute coronary syndrome (ACS). Although the detection of vulnerable plaques by coronary CT (CCT) has been examined and reported, there has been no report on the detection of disrupted plaques by CCT.

Objectives To test the ability of CCT to detect disrupted coronary plaques.

Methods 32 consecutive patients with suspected ischaemic heart disease who underwent successful coronary angioscopic examination and CCT were analysed. Yellow plaques of colour grade 1−3 and disrupted yellow plaques were examined by angioscopy. CCT findings (low attenuation, positive remodelling and ring-like enhancement) were examined for each site of yellow plaques.

Results In the 32 patients, 65 yellow plaques were detected. Higher-colour-grade yellow plaques and disrupted yellow plaques had a significantly higher incidence of CCT findings: low attenuation (grade 1 vs grade 2 vs grade 3, 18% vs 59% vs 69%; non-disrupted vs disrupted, 36% vs 66%), positive remodelling (24% vs 59% vs 75%; 33% vs 75%), and ring-like enhancement (0% vs 19% vs 25%; 6% vs 44%). Positive and negative predictive values for ring-like enhancement to detect disrupted plaque were 88% and 63%, respectively; those for the combined CCT findings (low attenuation, positive remodelling and ring-like enhancement) to detect disrupted plaque were 90% and 58%, respectively.

Conclusion CCT findings were associated with disrupted plaques confirmed by angioscopy. Ring-like enhancement had a high positive predictive value for detecting disrupted plaque.