Answer is D (Evaluation of Left Atrial Appendage Thrombi) Trans-esophageal echocardiogram (TEE) is preferred to Trans-thoracic echocardiogram (TTE) for smaller, atrial and posterior masses such as the Left Atrial Appendage Thrombi. TTE is the standard test for the noninvasive evaluation of pericardial disease. Identification of vegetations on tricuspid valves is no better overall by TEE than by TEE (as the tricuspid valve is equidistant from the chest wall and the esophagus). Very anterior masses, Such as left ventricular apical thrombi, are equally well and, far more easily imaged by TTE. Trans-esophageal echocardiogram (TEE) vs. Trans-thoracic echocardiogram (TTE) Trans-esophageal Echocardiography (TEE) is generally more sensitive than Trans-thoracic Echocardiography (TTE) and provides a unique window for high resolution imaging of posterior structures of the hea paicularly the left atrium, mitral valve and aoa. TEE is however an invasive and more expensive procedure and hence its indications must be weighed against these factors and TTE remains the initial investigation of choice for most situations. However if a high clinical index of suspicion remains after a negative or non-diagnostic transthoracic study, Trans-esophageal echocardiography should be considered. Situations in which Trans-esophageal echocardiography should be performed as the initial test of choice include Those patients in whom image quality on chest wall imaging is unacceptable. Those with prosthetic valves, and Those in whom complications such as abscess formation are suspected on clinical rounds.