- Etiology: barotrauma (pneumothorax or pneumomediastinum dissecting into abdomen), nasogastric tube perforating stomach, indomethacin used to close patent ductus arteriosus causing gastric ulcer, necrotizing enterocolitis, obstruction, blunt abdominal trauma
- CXR upright: air beneath diaphragm
- AXR upright: air beneath diaphragm
- AXR left lateral decubitus: air above the liver (air between abdominal wall and liver)
- AXR cross-table lateral: for small amounts of free air see tell-tale triangle sign of air between bowel loops, for large amounts of free air see air superiorly between abdominal wall and viscera
- AXR supine: overall increased lucency of abdomen, American football sign of falciform ligament, inverted Y of umbilical artery ligaments, Rigler’s sign (see air outlining both sides of bowel wall)
- Note:
— Neonates with bowel perforation have an inflamed abdomen and pneumoperitoneum may be loculated and not be classically seen on upright / decubitus / cross-table lateral views and pneumoperitoneum may appear as fixed air collection that does not appear to conform to bowel
— In such cases, US showing complex free fluid may assist in making the diagnosis of bowel perforation, keeping in mind the differential diagnosis of complex free fluid is bowel perforation / infection / hemorrhage
Radiology Cases of Pneumoperitoneum
Radiology Cases of Pneumoperitoneum on Upright AXR

Radiology Cases of Pneumoperitoneum on Decubitus AXR





Radiology Cases of Pneumoperitoneum on Cross-Table Lateral AXR


Radiology Cases of Pneumoperitoneum on Supine AXR









