Quantitative evaluation of myocardial ischemia by cardiac magnetic resonance imaging

The aim of this study is to evaluate the significance of transmural perfusion gradient (TPG) method with 3.0T MRI to detect coronary artery disease (CAD). Traditional quantitative analysis of transmural myocardial perfusion neglects that subendocardium is more vulnerable to ischemia than subepicardium. In contrast, TPG and relative TPG reserve (TPGR) can take it in account and should be useful for CAD diagnosis. 44 patients (35 men, age 61.5 ± 7.8 years) with known or suspected CAD underwent adenosine-stress CMR scan. Quantification of myocardial perfusion was based on exponential model by deconvolution technique. Quantitative coronary angiography (QCA) ≥ 70% stenosis was considered as anatomically significant. TPG and relative TPGR showed significant difference between ischemia and normal territories (TPG 0.72 ± 0.14 vs. 0.95 ± 0.18, stenosis vs. normal, respectively, P <; 0.0001; relative TPGR 0.82 ± 0.13 vs. 1.09 ± 0.11, P <; 0.0001). Area under curve (AUC) was 0.87 for TPG and 0.94 for relative TPGR. Relative TPGR yielded significantly better sensitivity and specificity of CAD diagnosis compared to myocardial blood flow (MBF), relative myocardial perfusion reserve (MPR) and TPG (P <; 0.0001) and appeared to be the most meaningful parameter to detect anatomically significant CAD.