What does the coffee bean sign on an x-ray indicate when associated with a dilated loop of colon?

The coffee bean sign on an x-ray is a classic radiological finding associated with certain types of bowel obstruction, particularly volvulus. In the case of a dilated loop of colon, this sign is most commonly linked to cecal volvulus.

Cecal volvulus occurs when the cecum twists upon itself, leading to obstruction. The dilated cecum appears on x-rays as a large, gas-filled structure that can resemble a coffee bean or a "kidney bean" shape due to the accumulation of gas and fluid. This distinctive appearance is particularly pronounced in the context of a cecal volvulus because the cecum is occupying a more medial position within the abdominal cavity, leading to this characteristic morphology on imaging studies.

Recognition of the coffee bean sign alongside a dilated loop of colon is critical for diagnosis and guides management, as cecal volvulus can lead to ischemia and necrosis if not addressed promptly through surgical intervention or endoscopic management. The sign aids in differentiating this condition from others that may present with obstruction but do not exhibit the same gross appearance on imaging.