Figure 1.

(a) Example image slice with oblique orientation showing the locations of the five aortic landmarks. The image slice is defined by the plane containing landmarks 1, 3, and 5. The dots for landmarks 2 and 4 are projections on that plane. (b) 3D schematic of the region of interest (ROI) extraction from the CT volume. The landmarks (yellow dots) are interpolated with a smoothing spline (black curve), from which orthogonal image slices are extracted. For visualization purposes, only seven slices are shown in this figure. The extracted image slices are simply stacked to obtain the ROI. (c) Cross-sectional views through the center of the ROI.