Background
The use of ultrasound enhancing agents (UEA) in echocardiography is a technique that can be used to enhance endocardial border delineation in studies with suboptimal left ventricular cavity visualization [1-3]. There are two different types of contrast agents that serve different purposes. The first one is agitated saline contrast which is frequently utilized to identify small right-to-left shunts such as patent foramen ovale or atrial septal defect [4]. The other is a newer technique consisting of microbubble contrast agents which traverse the pulmonary vasculature and opacify the left ventricle (LV), allowing for accurate endocardial border definition in patients with suboptimal echocardiograms [1]. This allows for improved sensitivities and specificities when comparing patients with poor echocardiographic windows to those with well visualized windows [3, 5]. In a large prospective study, patients with technically difficult echocardiographic studies were evaluated to see how UEA effected diagnosis and management. The percentage of uninterpretable studies decreased from 11.7% to 0.3%. Moreover, further procedures were avoided in 33% of patients and medical management was altered in 10% [1]. By decreasing need for additional procedures, use of UEA is cost effective. In terms of safety profile with UEAs, back pain is the most common complaint followed by headache and allergic reactions [6]. Application of UEAs have not been associated with significant extra cost of time and manipulations because small bolus injections have been shown to suffice for image quality [7]. Indeed, they have been shown to be cost-effective (4) and life-saving [8].