Plaque composition on ultra-high-resolution coronary computed tomography angiography with optical coherence tomography correlation

A 68-year-old man presented to our chest pain unit with angina and a low pre-test probability for coronary artery disease (CAD). Troponin levels were normal, and echocardiography showed an intact left ventricular function. Coronary computed tomography angiography (CCTA) was performed using a first-generation dual-source photon-counting detector computed tomography (PCD-CT, NAEOTOM Alpha®, Siemens Healthineers) in a novel ultra-high resolution (UHR) mode. Data were reconstructed at 0.6 and 0.2 mm to reflect the typical appearance on standard and PCD-CT scanners (Panels A/D and B/E, respectively). The RCX presented with a mixed plaque and moderate-to-severe stenosis, right coronary artery (RCA) with a soft plaque and moderate-to-severe stenosis (Panels A and B), and LAD with a mostly a calcified plaque and mild stenosis (Figure 1D). UHR reconstructions revealed a fibrous cap on the calcified plaque (Panel E). Subsequent invasive coronary angiography including optical coherence tomography (OCT) confirmed a significant stenosis in the RCA [Panel C, fibrous plaque with micro-calcifications (arrowhead)] and left circumflex coronary artery (LCX) (mostly fibrotic components). Both were successfully treated with drug-eluting stents [thrombolysis in myocardial infarction (TIMI) coronary grade flow 3 (TIMI 3)]. Further, OCT confirmed the mild stenosis of the LAD caused by lesion with a fibrous cap over the calcification (Panel F).