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.