Yoshitaka Goto MD, Presenter: Nothing to Disclose

Kakuya Kitagawa MD, PhD, Abstract Co-Author: Nothing to Disclose

Mio Uno MD, Abstract Co-Author: Nothing to Disclose

Shiro Nakamori MD, Abstract Co-Author: Nothing to Disclose

Motonori Nagata MD, PhD, Abstract Co-Author: Nothing to Disclose

Masaki Ishida MD,PhD, Abstract Co-Author: Nothing to Disclose

Yasutaka Ichikawa MD, Abstract Co-Author: Nothing to Disclose

Hajime Sakuma MD, Abstract Co-Author: Research Grant, Siemens AG Research Grant, Koninklijke Philips NV Research Grant, General Electric Company Research Grant, Bayer AG Research Grant, Guerbet SA

Dynamic myocardial perfusion dual-source CT (DSCT) allows for voxel-wise measurement of myocardial blood flow (MBF) of entire LV myocardium. Although previous DSCT studies used absolute MBF in mL/100g/min as a threshold to discriminate flow-limiting coronary artery disease (CAD), absolute MBF can be variable due to multiple factors other than physiological significance of coronary stenosis. Since the endocardial layer of LV myocardium is most susceptible to ischemia, transmural perfusion ratio (TPR) of absolute MBF may be a more useful indicator of flow-limiting CAD. The purpose of this study was to compare the diagnostic performances of absolute MBF and TPR for predicting flow-limiting CAD as defined by fractional flow reserve (FFR).

Thirty-three patients (68.2±8.5 years old; 26 males) without history of myocardial infarction underwent stress dynamic perfusion DSCT and invasive coronary angiography (CAG) within 90 days. Endo- and epicardial MBF in 16 segments were obtained from the quantitative analysis of DSCT perfusion datasets. TPR was given as endocardial MBF of a specific segment divided by the mean of epicardial MBF of all 16 segments. Minimal endocardial MBF (endo-MBF) and minimal TPR within each of the LAD, LCX and RCA territory were used for analysis. Flow-limiting CAD was defined as luminal diameter stenosis of >90% on CAG or lesion with FFR of ≤0.8. Diagnostic performance of stress DSCT perfusion was assessed in 91 vessel territories after exclusion of 8 moderately (50-90%) stenosed vessels where FFR measurements were not available.

Territories with flow-limiting CAD (39/91, 42.9%) showed significantly lower endo-MBF and TPR than those without (endo-MBF: 65.6±23.7 vs 82.5±27.0 mL/100ml/min, p=0.0009; TPR: 0.77±0.20 vs 0.95±0.19, p<0.0001). The area under the ROC curve of TPR was significantly greater than that of endo-MBF for detecting flow-limiting CAD (0.857 vs 0.702, p=0.016). With a cut-off value of 0.902, TPR showed sensitivity of 87.7% and specificity of 82.7%.

Endocardial-to-mean epicardial ratio of absolute MBF quantified by stress dynamic DSCT perfusion demonstrated higher diagnostic performance for discriminating flow-limiting CAD compared to absolute endocardial MBF.

Accurate assessment of hemodynamic significance of coronary artery stenosis can be achieved by stress dynamic perfusion CT with analysis of transmural perfusion ratio of absolute MBF.

Goto, Y, Kitagawa, K, Uno, M, Nakamori, S, Nagata, M, Ishida, M, Ichikawa, Y, Sakuma, H, Diagnostic Accuracy of Endocardial-to-Epicardial Myocardial Blood Flow Ratio for Detecting Significant Coronary Artery Disease with Dynamic Myocardial Perfusion Dual-Source CT..  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14010189.html