- Always abnormal
- Present when intestinal permeability increases or when there is increase in intestinal luminal pressure
- Neonatal necrotising enterocolitis, adults with gastric emphysema, intestinal obstruction, infection, Crohn disease
- Blunt abdominal trauma, invasive malignancies (colon, ovarian carcinoma)
- Duodenal perforation at ERCP
- Colitis following barium enema
- Gas radiates out of hilum
- Less gravity dependence than pneumobilia, more peripheral distribution
Imaging
- US: moving gas bubbles in portal vein. Aliasing artifacts on spectral display.
- CT and radiograph: evident when enough gas accumulates and is seen in periphery of liver
Read more
Sisk, Phillip B. “Gas in the portal venous system.” Radiology 77.1 (1961): 103-107.