Liver air: portal venous gas or pneumobilia?

Question 1Where does portal venous gas usually appear in the liver?

1. aIn the hepatic artery
2. bAt the periphery, near the capsule
3. cOnly at the hilum
4. dIn the gallbladder wall

Question 2Why does pneumobilia stay central?

1. aBile flows out to the capsule
2. bThe ducts are only at the periphery
3. cBile drains towards the hilum, so gas stays in the central ducts
4. dGas cannot enter the ducts

Question 3What does gas in the portal vein do to a pulsed-wave Doppler trace?

1. aNothing
2. bIt causes sharp, bright spikes
3. cIt reverses the flow
4. dIt removes the signal completely

Question 4A patient has pneumobilia two years after an ERCP and sphincterotomy. What does it most likely mean?

1. aBowel ischaemia
2. bLiver abscess
3. cAn expected finding after the sphincterotomy
4. dPortal vein thrombosis

Question 5An unwell patient with abdominal pain and a raised lactate has peripheral gas throughout the liver. What next?

1. aUrgent CT and surgical review for bowel ischaemia
2. bReassure: it is pneumobilia
3. cStart an ERCP
4. dRepeat the scan next week