Is Plain Radiography Sensitive Enough to Detect Pneumoperitoneum?

An upright chest radiograph shows a large amount of pneumoperitoneum under the right hemidiaphragm of a patient who has peptic ulcer perforation found at surgery.

Facts: Pneumoperitoneum & GI perforation

• Common
• Requires a breach through all layers of hollow viscus that would allow escape of intraluminal content into the peritoneal cavity
• Results in peritonitis, either localized or generalized

Detectability Rate of Imaging

• Plain radiography sensitivity ranges from 50% to 98% depending on the technique (upright chest, upright abdomen, left lateral decubitus, supine abdomen) and additional postural maneuver
• Recent study of 1,723 patients with GI perforation shows that radiography (either upright chest, upright abdomen or both) has positivity rate of almost 90%. 10% of radiographs did not show free air despite patients having GI perforation. Highest positivity rate was seen with gastric and duodenal perforation (94%), but lowest with appendiceal perforation (7%)

Reference:

Bansal J, Jenaw RK, Rao J, et al. Effectiveness of plain radiography in diagnosing hollow viscus perforation: study of 1,723 patients of perforation peritonitis. Emerg Radiol 2011 December.