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

To explore the epicardial adipose tissue (EAT) characteristics associated with left atrial appendage thrombus (LAAT) in patients with atrial fibrillation (AF).

This 1:1 individual-match (by age, sex, CHA₂DS₂-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.

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.

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.