Clinical study on coronary computed tomography angiography and myocardial perfusion imaging in quantitative assessment of flow-limiting stenoses

Objective To evaluate the diagnostic accuracy of a combined non-invasive assessment of coronary artery disease with coronary computed tomography angiography(CCTA) and myocardial perfusion imaging(MPI) for the detection of flow-limiting coronary stenoses and its potential as a gatekeeper for invasive examination and treatment.Methods A total of 78 patients with known or suspected coronary artery disease(CAD) were examined by adenosine stress/rest MPI and coronary angiography(CAG) within one month,at the same time these patients underwent CCTA with the same SPECT/CT facility.MPI was evaluated by semi-quantitative visual interpretation using a 15-segment model.According to CAG and CCTA standard,a significant stenosis was defined as a diameter reduction of ≥50%.Detection of flow-limiting stenoses(justifying revascularization) by the combination of CCTA and MPI(MPI/CCTA) was compared with the combination of CAG plus MPI(MPI/CAG),which served as standard of reference.Results In 78 patients,MPI image revealed 66 reversible,6 fixed and 6 normal.The distribution of the perfusion defects among the different coronary artery territories was as follows: reversible perfusion defects: left anterior descending artery(LAD)(n=55),left circumflex artery(LCX)(n=14),right coronary artery(RCA)(n=11);fixed perfusion defects: LAD(n=4);RCA(n=3).CCTA image analysis revealed a stenosis in 74/234 coronary arteries of 56/78 patients.MPI/CCTA image analysis revealed a stenosis in 56/78 patients.The diagnostic sensitivity,specificity,accuracy,positive and negative predictive values by MPI/CCTA vs MPI/CAG for the detection of flow-limiting coronary stenosis on patient-based and vessel-based analysis were 94.33%,72.00%,87.18%,87.71%,85.71% and 88.71%,92.44%,91.45%,80.89%,95.78%.All of revascularization procedures(46,100%) were associated with ischemia on MPI,but more than a third(25/67,37%)of revascularized vessels were not associated with ischemia on MPI.Conclusion The combined non-invasive approach MPI/CCTA has an excellent acuracy to detect flow-limiting coronary stenoses compared with MPI/CAG.Its advantage lies in the non-invasive evaluation of coronary anatomy and function,and its use as a gatekeeper appears to make a substantial part of revascularization procedures redundant.