Which radiographic sign is associated with sigmoid volvulus?

Which radiographic sign is associated with sigmoid volvulus?

• A. Coffee bean sign
• B. Double bubble sign
• C. Bent inner tube sign
• D. Lead pipe sign

Answer: (C)

The key idea is recognizing how sigmoid volvulus appears on imaging, especially with contrast studies. When the sigmoid twists on its mesentery, a contrast enema outlines a highly folded, narrowed loop of colon. This creates a bent, tube-like configuration—the bent inner tube sign—which reflects the twisted, curved lumen of the sigmoid. This appearance on contrast enema is a distinctive clue pointing to sigmoid volvulus because it directly visualizes the management-critical twist of the affected segment. Other signs can point to related ideas but reflect different scenarios. The coffee bean sign on plain abdominal x-rays is another clue for sigmoid volvulus, as a markedly distended sigmoid can resemble a coffee bean. But the bent inner tube sign specifically captures the enema view of a twisted sigmoid. The double bubble sign signals proximal intestinal obstruction like duodenal atresia, and the lead pipe sign indicates long-standing inflammatory bowel disease with loss of haustra.

The key idea is recognizing how sigmoid volvulus appears on imaging, especially with contrast studies. When the sigmoid twists on its mesentery, a contrast enema outlines a highly folded, narrowed loop of colon. This creates a bent, tube-like configuration—the bent inner tube sign—which reflects the twisted, curved lumen of the sigmoid. This appearance on contrast enema is a distinctive clue pointing to sigmoid volvulus because it directly visualizes the management-critical twist of the affected segment.

Other signs can point to related ideas but reflect different scenarios. The coffee bean sign on plain abdominal x-rays is another clue for sigmoid volvulus, as a markedly distended sigmoid can resemble a coffee bean. But the bent inner tube sign specifically captures the enema view of a twisted sigmoid. The double bubble sign signals proximal intestinal obstruction like duodenal atresia, and the lead pipe sign indicates long-standing inflammatory bowel disease with loss of haustra.