Hepatic Transplantation

 No reliable imaging findings to suggest or confirm diagnosis

• Biliary leak
image From entry of T tube: Easily treated

image From biliary anastomosis: Requires revision

image From intrahepatic ducts: Biliary necrosis; catastrophic

• Biliary obstruction
image Balloon dilation and stenting

• Hepatic artery stenosis
image Damped waveform in hepatic artery distal to stenosis: Slow systolic upstroke; decreased resistive index (< 0.5)

image Narrowing at hepatic artery anastomosis with turbulent flow, focally ↑ velocity (> 0.3 m/s)

image CT (or MR) angiography for detailed analysis

• Hepatic artery thrombosis
image Accompanied by biliary necrosis; catastrophic

• Hepatic arterial pseudoaneurysm
image From biopsy or surgical error

• Portal vein stenosis
image Uncommon: Treated by angioplasty and stent

• IVC anastomotic stenosis
image Can be suggested by US (anastomotic narrowing, turbulent, rapid flow across anastomosis), CT, or MR

• Recurrent disease within allograft
image Primary sclerosing cholangitis: Tends to recur

image Hepatocellular carcinoma

image Recurrent viral hepatitis or primary biliary cirrhosis

• Extrahepatic complications
image Abdominal fluid collections

image Post-transplant lymphoproliferative disorder

(Left) Graphic shows the typical anatomy for whole liver transplantation. Some liver is cut away to show anastomoses more clearly, as there are a number of common variations for vascular and biliary anastomoses.

(Right) Graphic shows the typical anatomy of an adult partial-liver recipient (living donor). Note the biliary-enteric anastomosis to a Roux limb. Complications are more common than for whole liver allografts due to the many transected vessels and ducts and the small size of the structures for anastomosis.

(Left) Axial CECT shows a “halo” of low density surrounding some of the portal veins. This is a typical feature of periportal lymphedema, which is common and of no clinical concern in the early post-transplantation setting.

(Right) T-tube cholangiogram shows a mild waist-like narrowing at the biliary anastomosis image without dilation of the upstream bile ducts. This is the normal appearance of a duct-to-duct anastomosis.



• Whole liver allograft (cadaver donor)
image Orthotopic liver transplantation (OLT)

image Included from donor
– Intact inferior vena cava (IVC)
image Anastomosed end-to-end or as “piggy-back” side-to-side

– Hepatic artery (HA)
image Anastomosed end-to-end, sometimes with aortic (Carrel) patch

– Portal vein (PV)
image End-to-end anastomosis

– Bile duct
image Anastomosed end-to-end with recipient duct (70%) or to Roux limb

• Cadaver split liver (2 halves to separate recipients)
image Right lobe to adult recipient (IVC, HA, PV, bile duct)

image Left lobe to child recipient (complex anastomoses)

• Living donor transplant
image Child recipient: Generally receives lateral segment of donor liver

image Adult recipient: Receives right lobe of donor

image Complex biliary and vascular anastomoses


Normal Post-Transplantation Findings

• Right pleural effusion (usually resolves spontaneously)

• Right adrenal hematoma
image Adrenal veins injured or ligated during OLT

image No clinical importance

• Periportal lymphedema
image Lucent “halo” around PVs and IVC

image No significance; resolves spontaneously

• Vascular and biliary anastomoses may show waist-like narrowing
image Should not have functional narrowing

image Normal indices on US: Hepatic artery
– Resistive index (RI): 0.5-0.7

– Rapid systolic acceleration time (< 80 ms)

– Flow velocity at anastomosis < 200-300 cm/s

image Portal vein
– Mild phasicity with respiration; no turbulent flow

image Hepatic veins (HV), IVC
– Triphasic waveforms reflective of cardiac contractility

• Biliary anastomosis
image Waist-like narrowing without dilation of upstream ducts

image Duct-duct anastomosis may be stented with T tube for several months
– Allows access for cholangiography
image Performed in early post-OLT and repeated as indicated

• Liver parenchyma
image Normal texture by all imaging modalities

image Partial liver recipients
– Liver grows to near normal volume within  months

Pre-Transplantation Evaluation

• Imaging and clinical evaluation of severity of cirrhosis and portal hypertension
image Size and morphology of liver

image Ascites, splenomegaly, extent of varices

image Presence and stage of hepatocellular carcinoma (HCC)
– Size, number, presence of vascular invasion, extrahepatic spread

– Early stage HCC may be good candidate for transplantation (receives increased MELD points)

image Model for end-stage liver disease (MELD)
– Based on etiology of cirrhosis, plus serum creatinine, bilirubin, and International Normalised Ratio (INR)

• Detailed evaluation of hepatic vessels
image Note any anomalies (e.g., “replaced” HA)
– Check for severe atherosclerosis, median arcuate ligament compression of celiac axis

image PV: Check for thrombosis, mural calcification, diminutive size

image HVs: Check for thrombosis (Budd-Chiari)

Allograft Rejection

• No reliable imaging findings to suggest or confirm diagnosis

• Clinical suspicion leads to US-guided biopsy of allograft
image US is best modality for guidance
– Safest, least expensive, least discomfort

Biliary Complications

• Biliary leak
image Leak from entry of T tube
– Often encountered after removal of T tube after several months

– Recognized by cholangiography, biliary scintigraphy, or aspiration of fluid collection identified by US or CT

– Easily confirmed by ERCP and treated by placement of temporary biliary stent

image Leak from biliary anastomosis
– Usually due to surgical error

– Often requires surgical revision of anastomosis

image Leak from intrahepatic ducts
– May be due to biopsy (resolves spontaneously)

– Usually due to biliary necrosis
image Result of HA stenosis or thrombosis

– Usually requires retransplantation in adults

image Strictures or irregularity of intrahepatic ducts
– Nonspecific

– Possible etiologies include incomplete distention (artifact), infection, rejection, ischemia, recurrent primary sclerosing cholangitis

• Biliary filling defects
image Stones: Usually late complication

image Debris: Cholangitis, infection, rejection, ischemia

image May respond to endoscopic sweeping of debris from duct ± temporary stent

Nov 16, 2016 | Posted by in GASTROINTESTINAL IMAGING | Comments Off on Hepatic Transplantation

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