Coffee-bean sign (sigmoid colon)

A.Prof Frank Gaillard et al.

The coffee-bean sign (also known as the kidney bean sign or bent inner tube sign4 ) is a sign on an abdominal plain film of a sigmoid volvulus although some authors have also used the term to refer to closed loop small bowel obstructions. Caecal volvulus may be mistaken with sigmoid volvulus and the number of air-fluid levels help in differentiating the two entities. In caecal volvulus only one air-fluid level is seen compared to sigmoid volvulus with a few air-fluid levels4

This thick 'inner wall' represents the double wall thickness of opposed loops of bowel, with thinner outer walls due single thickness.

Inspired signs
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Article information

rID: 1145
Section: Signs
Synonyms or Alternate Spellings:
  • Coffee bean sign
  • Bent inner tube sign

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Cases and figures

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    Figure 1: coffee bean
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    Coffee bean sign.
    Case 1: with perforation
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    Case 2
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    Case 3
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    Case 5: on virtual colonoscopy
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