MMRF Feb 06 Booklet_New.qxd

Abnormal masses (tumors, thrombi, vegetations) must be distinguished from normal cardiac structures that may mimic a mass. The echocardiographic evaluation of intracardiac masses is dependent on the ability to distinguish normal from abnormal findings.1 Erroneous diagnoses may lead to inappropriate medical therapy and even inappropriate surgery.3 Recognition of such normal variants depends on image quality and technique, as well as a physician’s experience.1 There are several normal structures and variants that may mimic a cardiac mass. The Eustachian valve, Chiari network, crista terminalis, pectinate muscles, moderator band, trabeculations, interatrial septal aneurysm and lipomatous hypertrophy of the interatrial septum are some examples of normal structures that are frequently mistaken for pathologic entities (figure 1).4,5 Other entities which may cause confusion and appear prominently on echocardiographic images include surgical sutures, internal pacemaker electrodes and intracardiac catheters. Table 1 summarizes these commonly encountered normal structures by their location in various cardiac chambers.