Myocardial perfusion imaging in the setting of coronary artery stenosis and acute myocardial infarction using venous injection of a second-generation echocardiographic contrast agent

Background: We hypothesized that by producing excellent myocardial opacification, venous injection of FS-069 coupled with intermittent harmonic imaging (IHI) can be used to determine the presence and severity of coronary stenoses during hyperemia, the size of the risk area during coronary occlusion, and the extent of myocardial salvage after reperfusion. Methods and Results: Twelve dogs were imaged both continuously and intermittently (every end systole) in the fundamental (2 MHz) and harmonic (transmit at 2 and receive at 4 MHz) modes. FS-069 (1 mL) was injected intravenously for all stages and modes of imaging. Myocardial video intensity was severalfold (P<.01) higher during IHI than all other modes of imaging. Perfusion defects were difficult to measure during continuous and intermittent fundamental imaging and during continuous harmonic imaging. In comparison, the defects were clearly demarcated during IHI. When this mode was used, the magnitude of perfusion mismatch during hyperemia in the presence of a coronary stenosis correlated closely with the magnitude of flow mismatch when radiolabeled microspheres were used (r=.94). The perfusion defect sizes during coronary occlusion and reperfusion also correlated closely with postmortem risk area (r=.89) and infarct size (r=.96), respectively. Conclusions: Venous injection of FS-069 coupled with IHI produces excellent myocardial opacification. This approach can be used to determine the severity of coronary stenoses during hyperemia, the size of the risk area during coronary occlusion, and the extent of myocardial salvage after reperfusion. This approach, therefore, holds promise in the clinical setting.