LAA Morphological and Functional Parameter Assessment
The morphology of the LAA was assessed from 3D LGE images using
particle-based modeling (PBM) for statistical shape analysis (SSA).
Briefly, after contouring and segmentation by trained observers, we
created a three-dimensional reconstruction of the LAA. SSA using
particle-based modeling was performed on the LAA reconstruction to
define the shape class. For LAA ostium measurements, we used three
planes on the CMR to define the ostium and estimate its maximal
diameter, minimal diameter, circumference, and surface area. The ostium
of the LAA was first defined on the transversal image by the plane that
connected between the base of the Coumadin ridge and the proximal left
circumflex artery. The cross-section of the LAA ostium was created from
orthogonal projections in the coronal plane. The maximum and minimum LAA
ostium diameters were measured from the sagittal image. The
circumference and surface area were then calculated and provided by the
software. Figure 1 shows the procedural steps for registration of the
pre- and post-ablation LGE-MRI images to ensure spatial alignment as
well as for measurement of the LAA ostium.