Fig. 2.

Contrast-enhanced CT scans of the abdomen demonstrating volvulus of the transverse colon. Axial scans (A) show an abrupt caliber change (“beak sign” [red arrows], common in many types of mechanical ileum) representing the site of occlusion, associated with proximal air-fluid level (yellow arrows). Coronal view (B), obtained with multiplanar reconstructions (MPR), demonstrates the same loop twisting around the long axis of its meso (“whirl sign” [red circles]); most of the right colon is displaced, as well as jejunal loops (medially), due to partial involvement of the root of the mesentery. Significant right colic dilatation (with atony) is present, with a caliber of caecum measuring more than 17 cm and an evident air-fluid level (C [yellow arrows]).