Figure 3.

Illustration of the automated chest space segmentation. The innermost points of the bones on transverse slices are first ordered by the angle they form from the body center. Measured from the body center, if any two points form a low angle of less than 12° between them and are located on the dorsal side, the further one is removed from the point list. The remaining points are then connected by a smooth closed spline (shown in red) that is filled to create the chest space mask (A). If no angular filtering was applied to the points, the mask would be too inclusive in this case (B).