A Diagnostic Pitfall of Transthoracic Echocardiography: A Case of a Missed Large Mitral Valve Thrombus in the Setting of Suspected Nonbacterial Thrombotic Endocarditis.

Transthoracic echocardiography (TTE) is frequently utilized in the initial evaluation of cardioembolic stroke. However, the diagnostic utility of TTE is often operator-dependent, and in conjunction with anatomical limitations, there is a range of sensitivities reported in the literature specifically in the evaluation of nonbacterial thrombotic endocarditis (NBTE). Thus, relying on TTE findings to rule out NBTE in the setting of cardioembolic stroke evaluation can lead to misdiagnosis in the absence of confirmatory transesophageal echocardiography (TEE).