To compare the diagnostic accuracy of dynamic first pass computed tomography perfusion imaging and the transluminal attenuation gradient derived from coronary computed tomographyangiography in the assessment of coronary artery stenosis.

34 patients with suspicion of coronary artery disease, who underwent invasive coronary angiography and assessment of intermediate coronary artery lesions (50-75% diameter reduction) by an invasive pressure wire examination (fractional flow reserve) were included. All patients underwent a coronary computed tomography angiography and a dynamic computed tomography perfusion examination under adenosine stress at a 256 slice computed tomography scanner with an 8 cm wide detector. Myocardial blood flow was determined using the dynamic first pass computed tomography perfusion data. Transluminal attenuation gradient was calculated as...

The area under the ROC curve was 0.92 (0.80 to 0.95) for myocardial blood flowand 0.64 (0.46 to 0.793) for transluminal attenuation gradient (p=0.002). The optimal threshold using Youden´s index was 1.51 fortransluminal attenuation gradientand 1.21 for myocardial blood flow. Sensitivity and specificity for detection of hemodynamically relevant coronary artery lesions were 71.4 (41.9- 91.4) and 73.2 (57.1- 85.8) fortransluminal attenuation gradient Sensitivity and specificity were 90.9 ( 8.7- 98.5) and 84.6 (65.1- 95.5) for myocardial blood flow. See Fig. 5

Myocardial blood flowderived from dynamic computed tomography perfusion imaging of the myocardium is superior compared to thetransluminal attenuation gradient derived from coronary computed tomography angiographyfor the assessment of coronary artery stenosis. In spite of being inferior to myocardial blood flow, transluminal attenuation gradient can be used in the assessment of coronary artery stenosis as it significantly improves the accuray of coronary computed tomography angiography without additional contrast medium or radiation exposure.

Transluminalattenuationgradientin coronary computed tomography angiography for determining stenosis severity of calcified coronary artery: a primary study with dual-source CT. Zheng M, Wei M, Wen D, Zhao H, Liu Y, Li J, Li J. Eur Radiol. 2014 Noninvasive evaluation of coronary collateral arterial flow by coronary computed tomographic angiography. Choi JH, Kim EK, Kim SM, Song YB, Hahn JY, Choi SH, Gwon HC, Lee SH, Choe YH, Oh JK. Circ Cardiovasc Imaging. 2014