The CT examination shows a markedly dilated sigmoid loop, which reaches all the way up to the diaphragm. Both ends of the sigmoid loop merge at a mesenteric swirl, located at the level of the promontorium (best appreciated on the coronal series). The colon proximal to the sigmoid is not particularly dilated, nor is there any small bowel distension. There are small amounts of fluid adjacent to the liver and in the pelvis.
The topogram shows the classic presentation of a sigmoid volvolus on conventional x-ray examination.