Figure 2.

The segmentation of pulmonary artery exemplified in a patient (top) and a matching control (bottom). (a) User-defined seed points placed in the trunk and pulmonary main initiate the segmentation; (b) the image was smoothed using anisotropic diffusion; (c) gradient map of smoothed image; (d) a sigmoid filter provides an edge image for (e) the fast marching level set segmentation; (f) the final 3D segmentation refined by geodesic active contours. For simplification, seed points are shown in the same axial slice, but they can be placed independently of each other.