Daniela Di Marco MD, Presenter: Nothing to Disclose

Manuela Giglio MD, Abstract Co-Author: Nothing to Disclose

francesca besana MD, Abstract Co-Author: Nothing to Disclose

Sandro Sironi MD, Abstract Co-Author: Nothing to Disclose

Pietro Spagnolo MD, Abstract Co-Author: Nothing to Disclose

to evaluate the diagnostic accuracy of two-phase cardiac CT in detecting left atrial appendage (LAA) thrombosis in patients with chronic atrial fibrillation referred for radiofrequency ablation using the CARTO 3 and NavX system. 

260 consecutive patients undergoing CARTO-guided radiofrequency ablation for atrial fibrillation were prospectively enrolled. All patients underwent both cardiac CT and TEE within a 3-hour period or less. Diagnostic accuracy of cardiac CT for detection of LAA thrombosis was computed using TEE as reference standard. CT scanning protocol included a standard early phase imaging to evaluate coronary arteries, pulmonary vein and LAA anatomy and a late phase imaging using prospective electrocardiographic gating 6 minutes after contrast media injection. To reduce the radiation dose, late phase imaging was limited to the left atrium and performed only when a LAA filling defect was found on early-arterial phase. Filling defects seen on added late-phase imaging as well as on early-phase imaging were categorized as thrombus. 

TEE demonstrated spontaneous echo contrast in 48 patients and thrombus in 6 patients. In 57 patients CT demonstrated LAA early filling defects and a late-phase imaging was performed. All the 6 thrombi diagnosed on TEE were correctly identified on cardiac CT. The overall sensitivity and specificity were both 100%. The calculated radiation dose of CT examination was 3,31 mSv for early-phase imaging and 0,16 mSv for late phase imaging.

two-phase cardiac CT is a noninvasive and accurate modality for detecting LAA thrombosis and differentiating thrombus from circulatory stasis. Cardiac CT may obviate routine TEE before radiofrequency ablation.

two-phase cardiac-CT could be a one-stop-shop examination in patients with AF before RF-ablation allowing to obtain accurate imaging of heart, pulmonary veins and exclude LAA thrombosis, avoiding TEE

Di Marco, D, Giglio, M, besana, f, Sironi, S, Spagnolo, P, Left Atrial Appendage (LAA) Thrombosis Exclusion with Two-phase Cardiac Computed Tomography (CT) in Patients with Atrial Fibrillation (AF): A Prospective Comparison Study with Transesophageal Echocardiography (TEE).  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14004485.html