• Coronary Artery Stenosis in High-risk Patients: 64-Section CT and Coronary Angiography Prospective Study and Analysis of Discordance

    Herve Gouya, MD Olivier Varenne, MD, PhD Ludovic Trinquart, MSc Emmanuel Touze, MD, PhD Olivier Vignaux, MD, PhD Christian Spaulding, MD Jean-Louis Mas, MD, PhD Jean-Louis Sablayrolles, MC

    Purpose: To assess the diagnostic accuracy of multisection (64-sec­tion) computed tomography (CT) versus coronary angiog­raphy in detection of and assignment of grades for coro­nary artery stenoses in a high-risk population and to inves­tigate causes for discordance between the two.

    Materials and Methods: The protocol was approved by the local ethics committee. Patients gave informed consent. The study included 114 patients (103 men, 11 women; mean age, 63 years ± 8.2 [standard deviation]) with potential myocardial ischemia. Multisection CT images were interpreted independently by two radiologists with unequal experience in reading coro­nary CT angiograms. Diagnostic performance of 64-sec-tion CT in detection of stenoses of 50% or more was assessed per patient, per artery, and per segment. Interra-ter agreement was assessed by using the Cohen K coeffi­cient. Agreement between 64-section CT and coronary angiography for assigning grades to stenoses was assessed by using Bland-Altman analysis.

    Results:Sixty-eight percent of patients had stenoses of 50% or more. Good interrater agreement was found, with k values of 0.77-0.85. For the most experienced radiologist, the sensitivity, specificity, positive likelihood ratio, and nega­tive likelihood ratio were 73.4%, 95.0%, 14.7, and 0.28 per segment, 95.2%, 94.7%, 18.0, and 0.05 per artery, and 100%, 89.2%, 9.26, and zero per patient, respec­tively. Discordance between 64-section CT and coronary angiography was related to either under- or overestima-tion of the degree of stenosis, anatomic misclassification, and coronary artery segments that were not assessable at 64-section CT. Bland-Altman analysis showed poor agree­ment, especially for intermediate stenosis (mean bias, 1.3%; 95% limits of agreement: -27.3%, 29.9%).

    Conclusion:Despite excellent sensitivity and negative likelihood ratios in a per-patient or per-vessel analysis, some coronary artery stenosis remained misdiagnosed with 64-section CT, resulting in limited sensitivity on a per-segment basis owing to anatomic discordance and failure to accurately quantify intermediate stenosis.