Contrast Echocardiography: Current Applications and Future Perspectives

Abstract

Contrast echocardiography is an established imaging method and an essential tool in every state of the art echocardiographic laboratory. It has also been the subject of several major clinical and research studies during the last year. This article addresses the impact of these studies on the clinical use of contrast echocardiography. Most recent studies have been performed with commercially available ultrasound contrast agents, which cross the pulmonary vasculature and are used for assessment of the left heart. The principle licensed indication for these contrast media is the delineation of left ventricular (LV) borders, masses, and aneurysms. The superiority of 2-dimensional contrast echocardiography over nonenhanced 2-dimensional imaging has been confirmed for assessment of LV volumes and ejection fraction, and there is growing evidence for the use of contrast 3-dimensional echocardiography. Two studies have demonstrated the usefulness of contrast-enhanced TEE for detection of thrombi in the left atrial appendage. The improved endocardial definition seen with ultrasound contrast media can also be used for strain analysis on selected systems. In stress echocardiography, contrast has been used for myocardial perfusion imaging in addition to assessment of regional LV wall motion. A large European multicenter study has demonstrated Sonovue-enhanced myocardial contrast echocardiography to be more sensitive than nuclear single photon emission computed tomography (SPECT) for the detection of significant coronary artery disease. Two further studies are discussed, which have demonstrated the impact of isolated perfusion defects on patients’ outcome. In addition, several publications have supplemented existing evidence regarding the safety of commercially available contrast agents. Recent studies continue to establish the usefulness and safety of contrast echocardiography for the currently licensed indications. There is also now good evidence for the use of myocardial contrast echocardiography as an alternative to nuclear imaging.