Association between epicardial adipose tissue imaging characteristics and left atrial appendage thrombus in patients with atrial fibrillation

Aim: To explore the epicardial adipose tissue (EAT) characteristics associated with left atrial appendage thrombus (LAAT) in patients with atrial fibrillation (AF). Methods: -VASc score, and anticoagulant use) study respectively enrolled 95 pairs of patients, comparing those with and without LAAT. EAT parameters derived from cardiac computed tomography angiography (CTA)-including volume, mean CT attenuation (CTmean), and radiomic features-were extracted and analyzed for their association with LAAT. Results: On contrast-enhanced CT, the mean CT attenuation of EAT was significantly higher in patients with LAAT than in those without at both 1 mm (median [IQR]: -75 [-88 to - 71] vs. - 71 [-86 to - 65.5], P < 0.01) and 3 mm (median [IQR]: -81 [-83.5 to - 78] vs. - 74 [-77.5 to - 72], P < 0.01) from the LAA boundary. However, no significant difference was observed at 5 mm (median [IQR]: -87 [-90 to - 85] vs. - 86 [-89 to - 83], P > 0.05). Relative EAT volume was not significantly associated with LAAT. Eight radiomic features were selected using least absolute shrinkage and selection operator (LASSO) regression to generate a radiomics score. The radiomics score was significant associated with LAAT, independent of clinical characteristics and traditional CT parameters of EAT. Conclusion: Imaging characteristics of EAT surrounding the LAA in patients with AF, particularly increased mean CT attenuation and radiomic features, were found to be associated with the presence of LAAT.