Myocardial contrast echocardiography

Myocardial contrast echocardiography

Myocardial contrast echocardiography: Myocardial contrast echocardiography (MCE) uses gas filled microbubbles to image the microcirculation of the heart. The bubbles have rheological properties similar to that of red blood cells and they remain solely within the vascular tree. The bubbles are administered at an infusion rate to match the bubbles destroyed by the ultrasound energy so that steady myocardial contrast is obtained. MCE can be used to assess the infarct size a few days after the infarction when the reactive hyperemia has subsided. In this way it can be used to assess the success of reperfusion. MCE can also provide information on the collateral circulation in the presence of coronary occlusion. Stress echocardiography can also be combined with MCE. But it is difficult to perform MCE during treadmill exercise. Hence vasodilator stress is preferred, which will also avoid the problems due to tachycardia and tachypnea which may be associated with dobutamine stress echocardiography. Normal myocardium should fill within 5 seconds and in vasodilator stress if the hyperemia is 5 times, it should fill in 1 second so that the 5 second rest image will be like the 1 second stress image. If a region does not show this feature, it is likely to be due to coronary narrowing. In contrast to regional flow abnormalities, global abnormalities would suggest reduced flow reserve due endothelial dysfunction in hypertension, diabetes mellitus or dyslipidemia.