Comparative Study between Multislice Computed Tomography Coronary Angiography and Invasive Coronary Angiography in Diagnosis of Mid and Distal Segment Coronary Artery Stenosis

Abstract
Background: Computed Tomography Coronary Angiog-raphy (CCTA) is a promising method for detection and exclu-sion of obstructive coronary artery stenosis. Mid and distal segments of coronary arteries were chosen because they are usually small in caliber especially distal segment (usually less than 1.5mm) and they are affected by cardiac motion on the contrary, the proximal segment is always away from the myocardium and usually larger in diameter so that it can be easily diagnosed by CCTA.
Objective: The purpose of this study was to evaluate the added value of CT coronary angiography for detecting Coro-nary Artery Disease (CAD) in mid and distal segment lesions using invasive coronary angiography as a reference standard.
Methods: We prospectively evaluated 20 patients who suspected to have CAD and underwent CTA. we assessed mid and distal segment lesions using invasive coronary angiography as a reference standard. We excluded proximal segment lesion, high calcium score (800), arrhythmias, post percutaneous coronary intervention and post coronary artery bypass graft.
Results: A total of 20 subjects underwent both CCTA and ICA (60% were females with mean age: 58.1 years). On a patient based model, the sensitivity, specificity, and positive and negative predictive values to detect mid segment lesions were 88.9%, 95.2%, 88.9%, and 95.2% respectively and for distal lesions were 85%, 100%, 100%, 98.1%, respectively. Diagnosis of mid and distal segment lesions by both CT and coronary angiography showed statistically significant strong positive correlation.
Conclusion: CT angiography is a reliable tool and has high accuracy for detection of CAD in both mid and distal segment lesions. Importantly, the high NPV (97%) firmly establishes CCTA as an effective noninvasive method to rule out obstructive coronary artery stenosis in patient with mod-erate pre-test probability.