Identification of right-sided structures by contrast transesophageal echocardiography, with emphasis on patent foramen ovale

The concept of contrast echocardiography, wherein any biologically compatible solution containing microbubbles of air, when injected into the circulation, makes the blood ‘echogenic’is not a new one. This has been used extensively with both M-mode echocardiography and 2D echocardiography since the early 1970s [1–6]. The applications of contrast echocardiography include structure identification, diagnosis or exclusion of intracardiac shunt, diagnosis of complex congenital heart disease, quantitation of valvular regurgitation, myocardial perfusion and improved quantitation of the left ventricle including delineation of the walls [2, 3, 6–21]. Although both transthoracic and transesophageal echocardiography are commonly used, much work in contrast echocardiography deals with transthoracic echocardiography. However, the same information could be extrapolated for use in transesophageal echocardiography.