Figure 5. Three-dimensional endoscopic views of the polyp obtained with conventional volume rendering. Although the polyp is depicted as a bumpy structure (arrow in A), it is difficult to identify it with this representation. In B, the voxels are colored according to their shape index values with the same color scheme as in Figure 4. The polyp (arrow) is clearly depicted and differentiated from folds and the colonic wall. A and B demonstrate the effectiveness of the shape index in differentiating polyps from other normal structures in the colon.