Figure 12b. Extrinsic compression appearing as a filling defect in the transverse colon. (a) Endoluminal CT image shows a large smooth filling defect (arrow). (b) Prone axial CT image shows that the filling defect (arrow) is partially extrinsic to the colon. (c) Coronal CT image shows the filling defect as a tubular structure (arrow), which represents a jejunal loop compressing the transverse colon.