Diagnostic Ultrasound - Abdomen and Pelvis

Biloma
TERMINOLOGY
Definitions
• Encapsulated collection of bile outside biliary tree
IMAGING
General Features
• Location
○ Intrahepatic or extrahepatic, in gallbladder fossa in
patients with recent cholecystectomy
Ultrasonographic Findings
• Grayscale ultrasound
○ Focal collection of fluid within liver or close to biliary
tree, e.g. in gallbladder fossa in patient with recent
cholecystectomy
○ Round or oval in shape and usually unilocular
○ Thin capsule wall usually not discernible
○ Anechoic fluid content suggests fresh biloma
○ Debris or internal septa suggest infected biloma
○ Posterior acoustic enhancement
○ May see echogenic foci at periphery related to clips from
recent surgery
• Color Doppler
○ No vascularity within lesion
○ For infected biloma, there may be increased vascularity
in adjacent tissue
• Needle aspiration under ultrasound guidance usually
required to confirm diagnosis (detection of bilirubin in
aspirate)
CT Findings
• Well defined or slightly irregular cystic lesion without
identifiable wall
• High-attenuation internal debris may be seen
• Subcapsular or intrahepatic biloma may result in adjacent
transient hepatic attenuation difference (THAD) on arterial
phase imaging secondary to mass effect and diminished
portal venous flow
MR Findings
• T1WI: Usually low but variable SI
• T2WI: High SI (same as gallbladder),internal debris can be
seen as low SI
• Delayed phase MR using hepatobiliary contrast agent can
determine bile leakage into biloma
Radiographic Findings
• Cholangiography may delineate leakage site:Extravasation
of contrast outside biliary tree
Nuclear Medicine Findings
• Hepatobiliary scintigraphy may demonstrate continual bile
leakage into biloma
Imaging Recommendations
• Best imaging tool
○ Ultrasound is good at lesion detection and provides
information on site & size of lesion for progress
monitoring or intervention
DIFFERENTIAL DIAGNOSIS
Perihepatic Collection/Seroma/Lymphocele
• May be anechoic or contain debris or loculations
• Thick, irregular wall may be present
• Difficult to distinguish from biloma; aspiration biopsy may
be required
Hepatic Cyst
• Variable appearance depending on whether it is sterile,
infected, or hemorrhagic
Hepatic Abscess
• Thick, irregular wall, surrounding vascularity
Intrahepatic Hematoma
• Echogenicity evolves over time:Echogenic initially,
hypoechoic after 4-5 days, internal echoes and septations
after 1-4 weeks
PATHOLOGY
General Features
• Etiology
○ Iatrogenic: laparoscopic cholecystectomy, post liver
transplantation, ERCP or other instrumentation of biliary
tree, liver biopsy
○ Post-traumatic: Blunt trauma, motor vehicle accident
○ Spontaneous rupture of bile duct
Gross Pathologic & Surgical Features
• Size of biloma depends on difference between leakage rate
and reabsorption rate of bile by peritoneum/surroundings
CLINICAL ISSUES
Presentation
• Most common signs/symptoms
○ Vague abdominal pain, nausea and vomiting, fever,
leukocytosis in case of infected biloma
Natural History & Prognosis
• Usually asymptomatic in simple biloma; most gradually
decrease in size over weeks
Treatment
• Percutaneous drainage if large or infected
• ERCP stent placement to decrease biliary pressure and
control leak
• Surgical resection and repair reserved for complicated
cases unresponsive to drainage
DIAGNOSTIC CHECKLIST
Consider
• Other causes of fluid collection: Ascites, abscess,
hematoma
SELECTED REFERENCES
1. Thompson CM et al: Management of iatrogenic bile duct injuries: role of the
interventional radiologist. Radiographics. 33(1):117-34, 2013
2. Frydrychowicz A et al: Hepatobiliary MR imaging with gadolinium-based
contrast agents. J Magn Reson Imaging. 35(3):492-511, 2012
Diagnoses: Liver
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