Prediction of calcified nodule using coronary CT angiography

Background Calcified nodule is one of the most difficult lesions to treat for interventional cardiologists because calcified nodule often requires debulking devices and the prognosis of calcified nodule is often poor. OCT (Optical coherence tomography)/OFDI (Optical frequency domain imaging) are useful tools to evaluate calcified plaque with calcified nodule although it is limited when OCT/OFDI cannot be delivered. On the other hand, coronary CT angiography (CCTA) is a non-invasive imaging to detect coronary artery stenosis and calcification. Appearance of calcified nodule is often irregular by CCTA. However, CCTA has not been used to evaluate CN in calcified lesions. Therefore, we aimed to compare CCTA finding and OCT/OFDI findings in calcified lesions. Methods We reviewed cases who underwent preprocedural CCTA and percutaneous coronary interventions with OCT/OFDI from March 2016 to August 2024. Calcification by OCT/OFDI was classified into calcified nodule, nodular calcification or sheet of calcium. Because of its specific irregular surface, we named popcorn type for irregular calcification of CN by CCTA. Calcification by CCTA was classified into popcorn type and non-popcorn type and evaluated each primary lesion using the Agatston score. These findings were compared. Results A total of 216 lesions from 192 patients were analyzed. Representative images of OCT/OFDI with corresponding CCTA images are shown in figure1. Calcified nodule, nodular calcification, and sheet calcium were identified in 23 cases/21 patients, 36 cases/34 patients, and 157 cases/143 patients, respectively (Table 1). As shown in figure 2-1, popcorn-type calcification by CCTA was common in CN compared to NC and SC (91.3% vs. 3.8%, p<0.001; 91.3% vs. 44.4%, p<0.001). Non-popcorn type calcification was more prevalent in sheet calcificatiion compared to CN and NC (96.2% vs. 8.7%, p<0.001; 96.2% vs. 55.6%, p<0.001). The median of calcium score (IQR) for the culprit coronary artery was 1105.3 (516.9–1693.8) in CN, 660.1 (323.2–997.1) in NC, and 537.2 (384.2–690.1) in SC (figure 2-2). CN had significantly higher calcification scores than SC (p=0.007) and showed a trend toward higher scores than NC (p=0.16). No significant difference was found between SC and NC (p=0.44). Conclusion Popcorn type calcification by CCTA was a strong predictor of CN by OCT/OFDI.