Supine film: There is a well delineated portion of large bowel with the
appearance of air outlining the mucosal edges on the right. This
represents intramural air.
CT: Intramural air is observed within the large and small bowel.
For example, in image 45 look to the right of the psoas musculature.
Observe the focus of contrast within the small bowel which is completely
surrounded by air.