Limitations and Potential Clinical Application on Contrast Echocardiography

Myocardial contrast echocardiography (MCE) is a relatively simple myocardial perfusion imaging technique which should be used in different clinical settings. The ability of MCE to provide a comprehensive assessment of cardiac structure, function, and perfusion is likely to make it the technique of choice for non-invasive cardiac imaging. Contrast agents are encapsulated microbubbles (MB) filled with either air or high-molecular-weight gas. They are innocuous, biologically inert and when administered intravasculary, the sound backscatter from the blood poll is enhanced because MB have the enormous reflective ability due to a large acoustic impedance mismatch between the bubble gas and surrounding blood. MCE is an ideal imaging tool for the assessment of left heart contrast and the myocardial microcirculation. MCE detects contrast MB at the capillary level within the myocardium and, thus, has the potential to assess tissue viability and the duration of the contrast effect. MCE was equivalent to SPECT for the detection of CAD with a tendency toward higher sensitivity of MCE compared with SPECT in microvascular disease and CAD. MCE is also a bedside technique that can be used early in patients presenting with acute heart failure to rapidly assess LV function (regional and global) and perfusion (rest and stress).