Biloma

Published on 19/07/2015 by admin

Filed under Radiology

Last modified 22/04/2025

Print this page

rate 1 star rate 2 star rate 3 star rate 4 star rate 5 star
Your rating: none, Average: 0 (0 votes)

This article have been viewed 3066 times

 Usually simple in appearance, but may rarely have internal debris, blood products, etc.

image No identifiable capsule/peripheral enhancement
• MR: Usually well-defined fluid collection, which is T2WI hyperintense and T1WI hypointense

image Hepatobiliary contrast agents (e.g., Eovist) are excreted into biliary tree and may identify site of bile leak in hepatobiliary phase
image Standard MRCP cannot definitively identify site of bile leak or differentiate biloma from other fluid collections
• Hepatobiliary scintigraphy: Focal accumulation of radiotracer outside biliary tree and bowel
• ERCP: Can delineate site of leakage and guide treatment

PATHOLOGY

• Most commonly the result of iatrogenic injury to biliary tract

image Cholecystectomy (especially laparoscopic), radiofrequency ablation of focal hepatic lesions, percutaneous liver biopsy, liver transplantation
• Traumatic bile leaks due to blunt or penetrating trauma can occur but are relatively uncommon

CLINICAL ISSUES

• ERCP with sphincterotomy and plastic stent placement (to decrease biliary pressure and control leak) is effective in majority (> 90%) of cases
• Percutaneous drainage of collection (often under image guidance) if biloma is large, infected, or increasing in size
• Biloma associated with transection of extrahepatic duct may require hepaticojejunostomy
image
(Left) Axial CECT in a patient who had recently undergone partial hepatectomy demonstrates development of a biloma image in the surgical bed.

image
(Right) Frontal ERCP image in the same patient demonstrates active extravasation image of contrast into the biloma from the right hepatic lobe bile duct distribution. Unlike other imaging modalities, ERCP can definitively identify an active bile leak and confirm that a fluid collection represents a biloma.
image
(Left) Axial CECT in a patient with fever and abdominal pain 21 days after a laparoscopic posterior segment wedge resection of a small hyalinized hemangioma shows a central right lobe biloma image and surrounding devascularized, infarcted liver image.

image
(Right) ERCP of the same patient shows a bile leak with spillage of contrast image into the biloma, and an appropriately positioned drain image. The biloma completely resolved after percutaneous drainage and biliary stent placement.

TERMINOLOGY

Definitions

• Loculated collection of bile within abdomen resulting from bile leak

IMAGING

General Features

• Best diagnostic clue

image Loculated fluid collection of simple fluid attenuation in close proximity to liver or biliary tree
• Location

image Either intrahepatic or extrahepatic

– Most commonly perihepatic (gallbladder fossa, Morison pouch) and subphrenic
• Size

image 2-20 cm
• Morphology

image Usually encapsulated and rounded
image May be lentiform if subcapsular

Imaging Recommendations

• Best imaging tool

image CECT or Tc-99m IDA
• Protocol advice

image Biliary scintigraphy: Sequential 1-minute acquisition for 60 minutes; static imaging at 2-4 hours and at 24 hours (if required)

Radiographic Findings

• ERCP can delineate site of leakage and presence of aberrant ducts that might change treatment approach

image May identify site of leak either within intrahepatic ducts or within extrahepatic bile ducts (e.g., cystic duct, common hepatic duct, or aberrant right hepatic duct)
image Can delineate injury to aberrant duct (e.g., aberrant right hepatic duct) that may change management

CT Findings

• Water-attenuation fluid collection within or adjacent to liver with exertion of mass effect on adjacent structures

image Usually simple in appearance, but may rarely have internal debris, blood products, etc.
image Usually no identifiable capsule or peripheral enhancement
• Subcapsular or intrahepatic biloma may result in adjacent transient hepatic attenuation difference (THAD) during arterial phase imaging (secondary to mass effect and diminished portal venous flow)

MR Findings

• Typically well-defined fluid collections, which are T2WI hyperintense and T1WI hypointense

image No internal/peripheral enhancement or capsule
• MRCP delineates relationship of biloma with adjacent biliary tree and anomalies in bile duct anatomy

image Cannot definitively identify site of bile leak or differentiate biloma from other fluid collections
• Hepatobiliary contrast agents (e.g., Eovist) are excreted into biliary tree and may identify site of bile leak

image Active extravasation visualized in hepatobiliary phase

– Delayed images helpful in patients with biliary dilatation or impaired hepatic function to increase sensitivity
image High reported sensitivities for bile leaks (∼ 100%)
image Technique limited in patients with impaired liver function who may not demonstrate adequate excretion of contrast into biliary tree

Ultrasonographic Findings

• Usually simple intrahepatic/perihepatic fluid collection
• May have low-level echoes due to hemorrhage/infection

Nuclear Medicine Findings

• Hepatobiliary scintigraphy

image Focal accumulation of radiotracer outside biliary tree/bowel
image Delayed (24 hour) images to visualize slow leaks
image SPECT/CT may help improve specificity (differentiate true leak from radiotracer in bowel)

Image-Guided Biopsy

• Collection may be aspirated if there is uncertainty about etiology: High aspirated fluid/serum bilirubin ratio suggests biloma

DIFFERENTIAL DIAGNOSIS

Simple Hepatic Cyst

• Simple-appearing intrahepatic cyst with water attenuation < 15 HU
• No history of risk factors for biloma, such as surgery/trauma
• No mass effect or visible cyst wall/no radiotracer accumulation on biliary scintigraphy

Hepatic Hematoma

• Unencapsulated collection with attenuation higher than biloma (unclotted blood: 30-45 HU, clotted blood: > 60 HU)
• Unencapsulated: Conforms to intraabdominal compartment or space
• May have associated active arterial extravasation on arterial phase imaging

Hepatic Abscess

• Pyogenic: Multilocular, rim-enhancing fluid collection with thick wall and surrounding parenchymal low-density edema
• Amebic: Unilocular cystic mass with thick wall often located near liver dome in right lobe with surrounding peripheral low-attenuation zone of edema

Postoperative Fluid Collections (Seroma, Lymphocele, Hematoma, Abscess)

• May appear identical to biloma when adjacent to liver or biliary tree
• May require hepatobiliary scan or aspiration to differentiate from biloma

Loculated Ascites

• Water-attenuation fluid: Passively conforms to margins of peritoneal cavity
• Evidence of cirrhosis, carcinomatosis, fluid overload, or other causes of ascites

PATHOLOGY

General Features

• Etiology

image Most commonly the result of iatrogenic injury

– Cystic duct leak or common bile duct injury after cholecystectomy (most common)
– Post radiofrequency ablation of focal hepatic lesions
– Post perforation of bile duct following PTC, ERCP, sphincterotomy, or tube change
– Post percutaneous liver biopsy
– Post liver transplantation
image Traumatic bile leaks can occur either due to blunt or penetrating trauma, but are relatively uncommon

– Only 0.1% of trauma patients and 7% of patients with blunt hepatic trauma
– Usually due to compression of bile duct against vertebral column during trauma resulting in avulsion of CBD
– Often associated with multiple other injuries

Gross Pathologic & Surgical Features

• May have fibrous pseudocapsule if chronic
• Pus if infected biloma

CLINICAL ISSUES

Presentation

• Most common signs/symptoms

image Vague abdominal pain, persistent nausea, and vomiting
image Fever and leukocytosis if biloma is infected
image High aspirated fluid/serum bilirubin ratio

Demographics

• Epidemiology

image 0.8-1.1% incidence of significant bile leak after laparoscopic cholecystectomy

– More common after laparoscopic cholecystectomy (compared to open cholecystectomy)
image 2-25% incidence of bile leaks reported after liver transplant or hepatic resection
image Post biliary and gallbladder surgery

Natural History & Prognosis

• May be asymptomatic: Most bilomas gradually decrease in size spontaneously over weeks
• If symptomatic, usually present in 1st postoperative week
• More likely to be superinfected in patients with iatrogenic leak after cholecystectomy for acute cholecystitis

Treatment

• ERCP with sphincterotomy and plastic stent placement to decrease biliary pressure and control leak is effective in majority (> 90%) of cases

image Percutaneous drainage of collection (often under image guidance) if biloma is large, infected, or increasing in size
• Biloma associated with complete transection of extrahepatic duct may require hepaticojejunostomy

DIAGNOSTIC CHECKLIST

Consider

• Biloma when confronted by loculated fluid collection within or adjacent to liver/biliary tree in patient who has undergone hepatobiliary surgery or been victim of hepatobiliary trauma

Image Interpretation Pearls

• Loculated fluid collection with mass effect post biliary trauma
image
(Left) Axial CECT in a patient who had just undergone a Whipple procedure demonstrates a collection of gas and fluid image immediately adjacent to the hepaticojejunostomy. Given the proximity of the biliary anastomosis, a biloma was strongly suspected.

image
(Right) Coronal CECT in the same patient demonstrates placement of a percutaneous drain image into the collection image, as there was concern for superinfection. The collection was found to have markedly elevated bilirubin levels, in keeping with a biloma.
image
(Left) Axial CECT in a liver transplant patient with known hepatic artery thrombosis shows an intrahepatic collection image with a branching configuration that parallels the bile ducts, representing a biloma due to arterial thrombosis.

image
(Right) Fluoroscopic image in the same patient demonstrates a catheter image placed into the biloma. Injection of contrast opacifies both the biloma image and nondilated ducts image, confirming communication between necrotic bile ducts and the biloma.
image
(Left) Axial CECT image obtained in a patient who presented with blunt abdominal trauma demonstrates a hepatic fracture image traversing the liver in the plane of the main lobar fissure.

image
(Right) Follow-up axial CECT performed 2 weeks later in the same patient, now presenting with RUQ pain, shows a large biloma image at the site of the previous hepatic fracture. Post-traumatic bilomas occur because of disrupted intrahepatic bile ducts and bile leakage into lacerations/hematomas.
image
(Left) Anterior dynamic views from a Tc-99m hepatobiliary study after liver transplant show tracer activity in the lateral perihepatic space image and none within the small bowel, compatible with a bile leak.

image
(Right) T1WI FS MR of a young woman obtained 1 hour after mangafodipir trisodium administration shows accumulated, extravasated, contrast-enhanced bile image within the gallbladder fossa post cholecystectomy. MR hepatobiliary agents may be particularly useful for delineating biliary injuries and bilomas.
image
(Left) Axial CECT of a patient with abdominal pain and fever a few weeks left lobe resection shows a gas-containing elliptical fluid collection image along the surgical margin of the liver.

image
(Right) ERCP of the same patient confirms a bile leak/biloma image. Asymptomatic post-traumatic/operative bilomas often resolve without intervention. Biloma growth, pain, and leukocytosis should, however, prompt treatment. This biloma was successfully treated by percutaneous drainage and antibiotics.
image
(Left) CECT of a patient with elevated liver function tests 2 years post liver transplantation shows a posterior segment biloma image. A CECT performed 1 month prior showed a thrombosed hepatic artery and small hepatic arterial collaterals.

image
(Right) Ultrasound of the same patient shows a hepatic dome biloma image. Liver transplant bilomas are typically due to hepatic arterial stenoses/thromboses. Biliary ischemia leads to bile duct necrosis, sloughing, and intrahepatic bilomas.
image
Axial CECT demonstrates a fluid collection image abutting the liver immediately adjacent to a recently created biliary-enteric anastomosis. The location of this collection raises strong suspicion for a biloma due to bile leak from the anastomosis.

image
Coronal CECT in the same patient demonstrates the biloma image to be immediately adjacent to the bile duct remnant image. A drain was placed and the bile leak resolved over time.
image
US of a transplant liver shows a complex cystic collection image of fluid with dependent debris. In the setting of dysfunction of a liver allograft, this is very suggestive of a biloma due to biliary necrosis secondary to hepatic artery stenosis or thrombosis. The finding of hepatic artery stenosis was confirmed on ultrasound (not shown).
image
Axial CECT in the same patient demonstrates an irregular fluid collection at the liver dome image, which was thought to communicate with the dilated biliary tree, in keeping with a biloma.
image
Transverse ultrasound of a 47-year-old woman with RUQ pain and a low-grade fever 1 week after laparoscopic cholecystectomy demonstrates a complex fluid collection image with low-level echoes and mass effect in the Morrison pouch between the caudal margin of the liver and the upper pole of the kidney.
image
Longitudinal color Doppler ultrasound in the same patient shows the complex fluid collection between the liver and the kidney image; needle aspiration revealed an infected biloma.
image
CECT of a 54-year-old man with right upper quadrant pain, leukocytosis, and a history of metastatic cholangiocarcinoma shows a well-defined hepatic dome fluid collection image, post radiofrequency ablation.
image
Ultrasound of the same patient performed prior to drainage shows a complex intrahepatic fluid collection image. Aspiration confirmed an infected biloma. Post-ablation bilomas occur because of thermal injury to intrahepatic ducts and bile leakage. Most post-ablation bilomas are asymptomatic.
image
Axial CECT in a patient with known hepatic artery stenosis after liver transplant based on angiographic findings (not shown) demonstrates a collection of gas and fluid image in the left hepatic lobe, strongly suggestive of an infected biloma. The biloma was drained via CT-guided catheter placement with resolution of the biloma and symptoms.

Share this:

Related posts:

Epithelioid Hemangioendothelioma Opportunistic Intestinal Infections Eosinophilic Gastroenteritis and Esophagitis Caroli Disease Colonic Metastases and Lymphoma Boerhaave Syndrome