2.4 Thickness measurement of the LA
As shown in Figure 1 , the atrial wall thickness (AWT) was
defined as the minimum distance from the manually determined endocardium
to the epicardial border on the LGE-MRI. Regions of interest were
manually drawn in specific atrial regions and the regions of interest
-based AWT was estimated in the multiplanar reconstruction images
perpendicular to the LA wall. To evaluate the AWT in the lesser LGE
areas associated with AF drivers, a receiver operating characteristic
(ROC) curve analysis was performed for the optimal values of the AWT
predicting AF drivers.