Clinical history: 51 year old man 1 month post liver transplant, now with fever, abdominal pain, and elevated LFTs.
Ultrasound shows decreased resistive index in the right, left, and main hepatic arteries, which is concerning for upstream hepatic artery stenosis. (However, this is not quite the classic tardus-parvus waveform.) There is also mild biliary dilation.
CT shows multifocal hepatic artery stenoses. Note the variant vascular anatomy. The transplant recipient had a replaced right hepatic artery arising from the SMA. The donor common hepatic artery was anastomosed to the recipients replaced right hepatic artery.
Normal hepatic artery resistive index is 0.5 to 0.7. Immediately post-transplant, mild transient elevations in resistive index are common, and have no clinical significance. However, a resistive index of 1 (i.e., no diastolic flow) suggests a downstream hepatic artery thrombosis.
Decreased hepatic artery resistive index suggests an upstream hepatic artery stenosis.
Biliary dilation post transplant can be seen with biliary strictures, which can be anastomotic or non-anastomotic. Anastomotic strictures tend to be short segment. Non-anastomotic biliary strictures tend to be longer, and could be due to ischemia or rejection.