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Coffee bean sign

AbdomenRadiograph / CT

A massively distended, gas-filled loop is folded on itself with a dense central line (the apposed walls) forming a giant coffee bean.

What it means

Sigmoid volvulus, a closed-loop obstruction from twisting of the sigmoid colon.

Mechanism

The sigmoid twists on its mesentery, forming a closed loop whose two apposed walls create the cleft (the coffee bean's midline).

Associated conditions

  • Sigmoid volvulus
  • Chronic constipation
  • Institutionalised or elderly patients
  • Redundant sigmoid colon

Pearls

  • The distended loop classically points toward the right upper quadrant.
  • The apex typically arises from the pelvis and overlaps the liver shadow.

References

  • Radiopaedia: Coffee bean sign (sigmoid volvulus)

For educational use only. This dictionary is a study aid and reference, not a diagnostic tool, and must not be used to guide clinical decisions or patient care. Imaging appearances vary; always correlate with the full clinical picture and confirm with a qualified radiologist.