Which CT finding is the most specific for identifying an internal hernia?

The mesenteric swirl sign is recognized as the most specific CT finding for identifying an internal hernia. This sign is characterized by the twisted appearance of the mesenteric vessels on imaging, which occurs due to the herniated bowel segment that is pulling or twisting the mesentery. This distinctive pattern on a CT scan can provide significant clues to the presence of an internal hernia, as it illustrates the abnormal positioning of the bowel and its associated vascular structures.

In contrast, small bowel obstruction can be caused by a variety of processes, not exclusively by internal hernias, and thus lacks the specificity required for a definitive diagnosis. Abdominal free fluid and pneumatosis intestinalis also serve different purposes in diagnosing gastrointestinal issues but are likewise not exclusive indicators of internal hernias, as they can occur in multiple abdominal conditions. Therefore, while other imaging findings might suggest bowel pathology, the mesenteric swirl sign stands out for its specificity when diagnosing internal hernias.