Figure 4a:

(a–d) Images show sigmoid carpet lesion detected at CT colonography in 56-year-old woman (patient 8). (a) Three-dimensional endoluminal and (b, c) 2D transverse CT colonography images show a 4-cm flat mass (arrowheads). The 3D view in a shows a central depression with a single CAD mark (blue area with arrow). Note oral contrast material coating the lesion in c, whereas there is no contrast material clinging to the healthy nondependent colonic walls. This lesion measured 4 mm in maximal height at CT colonography. (d) Same-day colonoscopy confirmed the carpet lesion, which proved to be a tubulovillous adenoma with high-grade dysplasia after laparoscopic sigmoid resection.