Multidetector Computed Tomographic Angiography Evaluation of Cases with Suspected Coronary Artery Pathology

Introduction: The aim was to to determine the sensitivity and specificity of CT in the detection of stenosis in the segments of major coronary artery by evaluating multidetector computed tomographic angiography (MDCT) and conventional angiography findings of cases planned to undergo catheter angiography for the first time due to suspected coronary artery disease, and to investigate the effect of heart rate on the quality of the scan. Materials and methods: In this prospective study, findings of 50 patients without any history of by-pass surgery or diagnostic or therapeutic catheter angiography, who were planned to undergo catheter angiography due to suspected coronary artery pathology in Başkent University Faculty of Medicine, Department of Cardiology, were comparatively evaluated by radiologists and cardiologists. Prior to CT scan, patients with sinus rhythm according to ECG monitoring were given premedication to lower the heart rate of 60 bpm or above. The patients were evaluated in 3 groups according to their heart rates (<60, 60-70, and >70 bpm). Major coronary arteries were evaluated in a total of 15 segments based on AHA (1975) classification. In CT scan, segments were divided into two groups as evaluable and non-evaluable. Identified stenoses were classified into 5 stages (Stage 0 = 0% (normal), Stage 1 = 1-49% (nonobstructive disease), Stage 2 = 50-74% (marked stenosis), Stage 3 = 75-99% (advanced stenosis), Stage 4 = 100% (occlusion)). Results: In 50 patients, 15 of which were female and 35 of which were male (mean age: 54.6 years), 684 (91%) of 750 coronary artery segments were considered evaluable for CT. For stenosis staging, CT sensitivity was 91% and specificity was 82%. Of the 66 coronary segments, 16 (24%) could not be evaluated due to motion artifact while 50 (76%) could not be evaluated due to the small diameter of distal coronary artery segment. It was striking that 56% of the segments that could not be evaluated due to motion artifact were right coronary artery and its branches, and 44% were circumflex artery and its branches. In the evaluation based on heart rate, CT accuracy rates were 94% for <60 bpm, 83.4% for 60-70 bpm and 92% for >70 bpm. Conclusion: For cases with suspected coronary artery disease and no previous history of by-pass or catheter angiography, CT scan comes forward as a very effective non-invasive diagnostic method with high specificity and sensitivity compared with catheter angiography.