Myocardial perfusion assessment in patients with medium probability of coronary artery disease and no prior myocardial infarction: comparison of myocardial contrast echocardiography with 99mTc single-photon emission computed tomography

Background No previous studies have compared myocardial contrast echocardiography (MCE) and single-photon emission computerized tomography (SPECT) for the detection of coronary artery disease (CAD) in patients with a medium likelihood of CAD. This study was developed to test the hypothesis that MCE is superior to SPECT for the detection of CAD. Methods Fifty-five patients with a medium probability of CAD and no previous myocardial infarction were recruited. Results of MCE and SPECT were compared to quantitative coronary arteriography, where CAD was defined as >50% stenosis. Each patient was examined for the anterior and posterior circulations. Results On a coronary circulation basis (n = 110), the sensitivity of MCE was significantly greater than that of SPECT for the detection of CAD (86% vs 43%, P < .0001). However, the specificities were similar (88% and 93%, P = .52). Both techniques were marginally more accurate in the anterior compared to the posterior circulation (88% vs 76%, P = .07 for MCE and 79% vs 63%, P = .19, for SPECT). On a patient basis (n = 55), MCE had a higher sensitivity than SPECT for the detection of CAD (83% vs 49%, P < .05). Although specificity tended to be higher for SPECT than MCE (92% vs 58%), it was not significant (P = .33). When CAD was defined as >40% coronary stenosis, the specificity of MCE increased to 83% without any change in sensitivity. Conclusion In this preliminary study, MCE was found to be superior to SPECT during dipyridamole stress for the diagnosis of CAD in patients with a medium pretest probability of CAD. Larger studies are required to confirm these findings.