Coronary Computed Tomography Angiography as a Method for Diagnosing a Thrombotic Occlusion of a Giant Right Coronary Artery Aneurysm in a Patient with Difficulty in Visualizing the Right Coronary Artery During Invasive Coronary Angiography

Giant coronary artery aneurysms, defined as those with a diameter exceeding 8 mm or a four-fold increase relative to the reference vessel segment, are incredibly rare, with an estimated prevalence of approximately 0.02% in the general population. We present computed tomography angiography images of a thrombotic occlusion of a giant right coronary artery (RCA) aneurysm. An 80-year-old Caucasian man with chronic coronary artery disease, who had undergone percutaneous coronary intervention of the middle segment of the left circumflex artery (LCx) with drug-eluting stent implantation, was referred to the computed tomography department for coronary computed tomography angiography (CCTA) due to difficulty visualizing RCA during invasive coronary angiography. In CCTA, a giant aneurysm in the proximal segment of the RCA, with a massive thrombus, communicating with the typical origin of the RCA from the right aortic bulb sinus, then extending into the occluded part of the proximal segment of the RCA, was visualised. The maximum long dimension of the RCA aneurysm was 5.3 cm, and the maximum short dimension of the RCA aneurysm was 4.4 cm. The maximum thrombus thickness in the RCA aneurysm was 2.2 cm. The middle and distal segments of the RCA, presumably filled with collateral circulation, have significantly weaker contrast, and contain numerous predominantly calcified atherosclerotic plaques. In summary, the presented CCTA images confirm the clinical importance of this modality in diagnosing coronary artery aneurysms, even in situations where the results of invasive coronary angiography remain equivocal. Due to higher spatial resolution, the ability to perform image reconstruction in multiple planes, the ability to detect thrombus, and the ability to assess the vessel wall and extracoronary structures, CCTA not only enables the detection of coronary artery aneurysms but also enables risk prediction, thus enabling the planning of a more optimal treatment strategy.