Utility of Nongated Multi-Detector Computed Tomography for Detection of Left Atrial Thrombus in Patients Undergoing Catheter Ablation of Atrial Fibrillation Matthew W. Martinez, Jacobo Kirsch, Eric E. Williamson, Imran S. Syed, DaLi Feng, Steve Ommen, Douglas L. Packer, Peter A. Brady Transesophageal echocardiography (TEE) is routinely performed to rule out the presence of atrial thrombi before ablation procedures in atrial fibrillation. Although TEE remains the current method of choice for detecting atrial thrombus, many patients scheduled for ablation procedures also undergo contrast-enhanced computed tomography imaging to characterize detailed anatomy for guidance of the electrophysiology procedure. In this paper, the authors present a series of more than 400 patients to demonstrate that contrast-enhanced computed tomography imaging, even if not electrocardiography-gated, allows for the reliable exclusion of the presence of left atrial thrombi and that an additional TEE might not be necessary in such selected cases.