Value of transluminal attenuation gradient of stress CCTA for diagnosis of haemodynamically significant coronary artery stenosis using wide-area detector CT inpatients with coronary artery disease: comparison with stress perfusion CMR

INTRODUCTION: This study aimed to evaluate the value oftransluminal attenuation gradient (TAG) of stress coronarycomputed tomography angiography (CCTA), using a wideareadetector CT in patients with coronary artery disease,compared to stress perfusion cardiac magnetic resonance(CMR) imaging. METHODS: This prospective study from May 2012 to January2015 included 21 patients with moderate coronary stenosison invasive coronary angiography. All patients underwentadenosine stress single-shot CCTA with a rest CCTA scanusing a wide-area detector CT. Coronary artery stenosis wasevaluated on both stress and rest CCTA images, and TAG wasmanually obtained for all vessels. Stress perfusion CMR wasused as a reference standard. A TAG cut-off value of –15.1HU/10 mm was applied for diagnosing haemodynamicallysignificant stenosis. The diagnostic accuracies of TAG andCMR were estimated and compared. RESULTS: TAG of stress CCTA in all coronary arteries hada sensitivity, specificity, and positive and negative predictivevalues of 90.5, 90.0, 86.4 and 93.1%, respectively.Corresponding values for TAG of rest CCTA in all coronaryarteries were 42.9, 83.3, 64.3 and 67.6%, respectively, whereasthose for TAG of coronary arteries with moderate stenosison stress CCTA were 93.3, 100, 100 and 92.3%, respectively.Mean effective radiation doses for stress and rest CCTA were10.6 ± 2.6 mSv and 2.3 ± 1.3 mSv, respectively. CONCLUSIONS: TAG of CCTA provided high diagnostic accuracyfor detecting haemodynamically significant coronaryartery stenosis. TAG of stress CCTA was more diagnosticallyaccurate, especially in coronary arteries with moderatestenosis.