Imaging Case of the Week 367 Answer

The erect chest x-ray shows free air under the diaphragms. The patient had an iatrogenic perforation of their bowel during an outpatient procedure causing pneumoperitoneum. The x-ray is interesting because the hemi-diaphragms especially on the right side is very thinned out and could be mistaken for an ECG wire.

The signs of pneumoperitoneum on an abdominal x-ray are –

  • Rigler’s sign (double wall sign)
  • Cupola sign (gas under the central tendon of diaphragm)
  • Continuous diaphragm sign.
  • Falciform ligament sign (in the upper abdomen)
  • Medial umbilical (inverted V sign)
  • Football Sign – large elliptical central abdominal lucency in the supine position.
  • Telltale triangle sign – triangular air pocket collection between small bowel loops in the supine position.

Reference: Grainger & Allison’s Diagnostic Radiology.