Comparative Assessment of Coronary CT Angiography and Invasive Coronary Angiography for Non Invasive Coronary Artery Disease Detection

Background: Coronary artery disease (CAD) is a leading cause of morbidity and mortality, necessitating accurate, early diagnosis. Invasive coronary angiography (ICA) remains the gold standard for detecting significant stenosis, but it carries procedural risks. Coronary computed tomography angiography (CCTA) has emerged as a non-invasive alternative, providing high-resolution imaging with lower risk. This study evaluates the diagnostic accuracy, clinical utility, and safety of CCTA compared to ICA. Material and Methods: A prospective observational study was conducted over 24 months at a tertiary care center. A total of 450 patients with suspected stable CAD underwent CCTA, followed by ICA if clinically indicated. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of CCTA were assessed using ICA as the reference standard. Secondary outcomes included plaque characterization, radiation exposure, contrast-induced nephropathy, and major adverse cardiovascular events (MACE) at six-month follow-up. Statistical analyses included receiver operating characteristic (ROC) curve analysis, inter-reader agreement using Kappa statistics, and Kaplan-Meier survival analysis. Findings CCTA demonstrated a sensitivity of 94.6%, specificity of 87.3%, PPV of 93.4%, and NPV of 89.1%, with an overall accuracy of 91.3% for detecting significant stenosis (≥50%). The ROC curve analysis yielded an AUC of 0.91, confirming excellent diagnostic performance. Radiation exposure was significantly lower in the CCTA group (5.2 ± 1.3 mSv) compared to ICA (7.8 ± 2.1 mSv, p < 0.01). MACE rates at six months were similar between groups (6.9% for CCTA vs. 8.9% for ICA, p = 0.58), demonstrating comparable long-term clinical outcomes. CCTA is a reliable non-invasive alternative to ICA, with high sensitivity, reduced radiation exposure, and comparable clinical outcomes. While CCTA may slightly overestimate stenosis in heavily calcified arteries, advancements in AI-assisted interpretation and FFR-CT may further refine its diagnostic accuracy. Given these findings, CCTA should be considered a first-line imaging modality for stable CAD evaluation, particularly in intermediate-risk patients