Pseudopneumoperitoneum

Pseudopneumoperitoneum describes any low attenuation within the abdominal cavity that masquerades as free intraperitoneal gas or pneumoperitoneum. Correctly identifying pneumoperitoneum is important, but making the diagnosis in error may lead to further unnecessary investigation or even surgery ¹.

Causes of pseudopneumoperitoneum include:

• basal linear atelectasis

• pneumomediastinum (mimicking cupola sign)

• Chilaiditi sign

• pseudo-Rigler sign

• diaphragmatic undulation

• gas within skin folds

• biliary, portal vein or bowel wall gas

• fat within the subdiaphragmatic space or the ligamentum teres

• properitoneal fat stripe

• benign post-traumatic pseudopneumoperitoneum

See also

• abnormal intra-abdominal gas

• pneumoperitoneum

• pneumoretroperitoneum

• pseudopneumoretroperitoneum