Figure 7. CT colonographic images of the supine view of a false-negative polyp (arrow in A) in the sigmoid colon. Although the polyp was 7 mm, it appears smaller than expected from the size, which was due mainly to the partial volume effect, and it also appears to be flat. On this view, the polyp did not contain adequate voxels with low curvedness values and high shape index to be detected. B, Prone view of the same polyp (arrow) as in A. The polyp appears rounder and larger than its supine counterpart; thus, it was depicted with the CAD scheme.