What is the role of imaging in the diagnosis of fluid collections following whole-liver orthotopic liver transplantation (OLTX)?

Updated: Mar 01, 2019
  • Author: Paul D Russ, MD; Chief Editor: John Karani, MBBS, FRCR  more...
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Answer

Postoperative fluid collections are common and can be supradiaphragmatic and infradiaphragmatic. As with other major hepatic surgeries, small, right-sided pleural effusions almost always develop after liver transplantation. These rarely complicate the postoperative course and usually resolve quickly.

In most patients, small parahepatic hematomas are present after surgery. Small hematomas are frequently noted on postoperative ultrasonograms obtained between 24 hours and 1-2 weeks after transplantation. Hematomas tend to be located in the gallbladder fossa and the hepatorenal space. They are depicted ultrasonographically as 2- to 3-cm lesions of variable echogenicity. Analogous findings are seen on CT and MRI scans. Virtually all small hematomas resolve spontaneously and without complications.

Occasionally, imaging shows small intraparenchymal fluid collections and defects in the transplanted liver. These include small contusions, hematomas, and innocuous bilomas. Fluid can be seen to accumulate in the fissure of the ligamentum teres. In patients who are doing well, these also are of little consequence.

A large volume of ascites can form after liver transplantation; they can result from cardiac decompensation with passive hepatic congestion, from allograft dysfunction and rejection, or from vascular complication. Because tense ascites can impair hepatic perfusion, damaging the allograft further, drainage of the ascites becomes necessary. This is easily performed by using imaging guidance and routine 8F catheter placement.

Bilomas are often associated with serious postoperative complications. They can reflect dehiscence of a choledochocholedochostomy or of a biliary-enteric anastomosis. Such dehiscence can result from technical problems or from ischemia at the anastomosis. As previously noted, ischemia resulting in biliary necrosis and biloma formation often is caused by hepatic artery stenosis (HAS) or thrombosis (HAT). In living-donor liver transplantation (LDLTX), bile can leak from the cut surface of the allograft if accessory or aberrant ducts are not noted and ligated or coagulated during surgery.

Bilomas can demonstrate a spectrum of imaging findings. Extrahepatic bile leaks can appear as free fluid or large, loculated collections adjacent to the liver or in other peritoneal spaces. During US and CT scanning, bilomas also can be seen as discrete, rounded, hypoechoic or hypoattenuated intraparenchymal lesions.

Bilomas can manifest as periportal cuffing, mimicking periportal edema. Although often amorphous, these peculiar-appearing bilomas usually reflect severe and extensive bile duct necrosis secondary to HAS or HAT and suggest a poor outcome for the graft.

Bile leaks can be confirmed by using nuclear medicine hepatobiliary scans. Small leaks can seal spontaneously. Other leaks require interventional or surgical correction.

Image-guided aspiration of a fluid collection can be necessary to determine its composition. Small, sterile parahepatic or intrahepatic bilomas can be treated expectantly or can be aspirated dry during sampling. Infected bilomas require percutaneous 8F catheter drainage, which is often performed in conjunction with other biliary and arterial interventions if underlying bile duct or vascular complications are present. [35] In patients with irreversible graft damage, percutaneous control of bilomas, particularly infected ones, can be a temporizing measure while retransplantation is pending.

In the setting of postoperative fever and sepsis, some hematomas must be aspirated to determine if superinfection is present. As determined by stat Gram staining and subsequent culturing, sterile hematomas are left to resolve spontaneously. Catheter placement in an uninfected hematoma is avoided, because semisolid subacute blood is not amenable to catheter drainage and because superinfection (by leaving an indwelling catheter) of an otherwise sterile collection is to be avoided.

Hepatic lymphatics are completely disrupted in the recipient. In the early period after transplantation, periportal fluid can originate in an accumulation of lymph; however, unlike renal transplantation, lymphoceles do not complicate liver transplantation. This is probably because of the intraperitoneal placement of the hepatic allograft, which allows lymph to be reabsorbed by the peritoneum.

Postoperative pyogenic abscesses in the abdomen or retroperitoneum can be treated percutaneously. Abscesses that have evolved from infected bilomas and vascular compromise require correction of the underlying problem. The occasional routine postoperative abscess unassociated with intrinsic graft complications can be treated successfully by using standard, image-guided, percutaneous catheter placement. In patients with uncomplicated abscess, 95% of isolated abscesses can be cured by means of catheter drainage and appropriate antibiotic coverage.


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