Clinical Value Of Myocardial Ischemic Coronary Artery Stenosis Caused By CTA Imaging Diagnosis

Objectives: To investigate the diagnostic value of coronary CT angiography(CTA) in detecting ischemia-inducing stenosis by comparing with myocardial perfusion imaging(MPI). Methods: We retrospectively studied30 patients with suspected or known coronary artery disease. They received coronary CTA, conventional coronary angiography(CCA) and MPI within two month. Coronary CTA was performed using 256-slice spiral computed tomography. A stenosis was classified as significant if the mean lumen diameter reduction was 50%. The coronary CTA results were documented to 13 coronary segments(modified AHA classification), and then were allocated to 4 coronary arteries(LM, LAD, LCX, RCA). The myocardial regions with decreased CT attenuation and wall thinning of left ventricular wall were recorded as infarcted areas. A two-day stress / rest MPI protocol was performed to all patients using 99Tcm-MIBI SPECT. Perfusion defects on MPI were allocated to corresponding coronary arteries according to the coronary perfusion type of subjects. Results: CCA diagnosis of 17 cases with coronary artery stenosis greater than or equal to 50%, a total of 29 vessels, 46 segments, 22 segments(49%) and in the distal branch of coronary artery. 83% percent of the total segments were evaluable, and 17%was unevaluable on coronary CTA. On segment-based analysis, the sensitivity, specificity, positive prediction value(PPV), negative prediction value(NPV) of coronary CTA in detecting significant stenosis for all segments and evaluable ones were 43%, 95%, 58%, 92% and 59%, 95%,58%, 95%, respectively. On vessel-based analysis, the sensitivity, specificity,PPV, NPV were 46%, 89%, 61%, 82%, 5 reversible and 3 fixed perfusion defects were identified by MPI in 8 of 28 patients. The sensitivity,specificity, PPV, NPV of CCA and coronary CTA in detecting reversible perfusion defects(myocardial ischemia) were 100%, 77%, 17%, 100% and57%, 81%, 12%, 98%, respectively. All of the 3 patients with fixed defects(myocardial infarction) demonstrated decreased CT attenuation and wall thinning in the corresponding myocardial regions. Conclusions: Coronary CTA has moderate sensitivity and specificity, high NPV, but lower PPV, in predicting myocardial ischemia. MPI remains mandatory for evaluating the functional relevance of coronary stenosis.