Bilomas refer to extrabiliary collections of bile. They can be either intra- or extrahepatic.
There is a slight discrepency in the reported literature in the use of the term "biloma". Many authors have used it exclusively to refer to intrahepatic bile collections or other bilious collections which are discretely organised rather than free biliary leak into the peritoneum.
Although usually asymptomatic, they may present with symptomatic bile peritonitis 7.
They can result from a number of causes:
- transcatheter arterial chemoembolisation (TACE)
- percutaneous ethanol injection
- microwave ablation
- percutaneous biliary drainage
- post surgical, e.g. injury to duct of Luschka following cholecystectomy 6
Seventy percent of bilomas are localized to the right upper quadrant, whereas the remaining 30% develop in the left upper quadrant. A biloma may wall off or may continue to demonstrate active bile leakage.
The goals of imaging in the assessment of biloma are:
- confirm the presence of a bile leak
- determine if it is extrahepatic or intrahepatic
- describe its extent
- assess for associated biliary obstruction
Bilious fluid is water attenuation, usually seen collecting in the right upper quadrant. CT intravenous cholangiography can demonstrate a communication between the biliary tree and the biloma, localising the leak.
Bilious fluid demonstrates variable signal intensity on T1-weighted imaging, and high signal intensity on T2-weighted imaging, similar to the signal intensity of gallbladder fluid.
Both gadolinium and manganese-based MRI contrast agents that are excreted through the biliary system are available. A delayed enhanced MRI examination using one of these agents may be useful to confirm that a localised fluid collection is composed of bile and to identify the site of bile leak 7.
A Tc99 diisopropyl iminodiacetic acid (DISIDA) scan is useful for confirmation of an active bile leak.
Treatment and prognosis
Treatment options include:
- pigtail drainage (under USG/CT guidance)
- surgical drainage
Management of bilomas can also involve treating any associated biliary tract obstruction which can both complicate and cause bilomas. Surgical repair of the source of underlying biliary tract bile leak may also be required.
General imaging differential considerations include:
- 1. Sakamoto I, Iwanaga S, Nagaoki K et-al. Intrahepatic biloma formation (bile duct necrosis) after transcatheter arterial chemoembolization. AJR Am J Roentgenol. 2003;181 (1): 79-87. AJR Am J Roentgenol (citation) - Pubmed citation
- 2. Shankar S, Vansonnenberg E, Silverman SG et-al. Diagnosis and treatment of intrahepatic biloma complicating radiofrequency ablation of hepatic metastases. AJR Am J Roentgenol. 2003;181 (2): 475-7. AJR Am J Roentgenol (citation) - Pubmed citation
- 3. Mueller PR, Ferrucci JT, Simeone JF et-al. Detection and drainage of bilomas: special considerations. AJR Am J Roentgenol. 1983;140 (4): 715-20. AJR Am J Roentgenol (citation) - Pubmed citation
- 4. Kwon HJ, Kim KW, Park JY et-al. Complications in living liver donors after partial liver procurement: an illustrative radiologic review. AJR Am J Roentgenol. 2007;189 (6): W338-43. doi:10.2214/AJR.07.2586 - Pubmed citation
- 5. Khalid TR, Casillas VJ, Montalvo BM et-al. Using MR cholangiopancreatography to evaluate iatrogenic bile duct injury. AJR Am J Roentgenol. 2001;177 (6): 1347-52. AJR Am J Roentgenol (citation) - Pubmed citation
- 6. Walker AT, Shapiro AW, Brooks DC et-al. Bile duct disruption and biloma after laparoscopic cholecystectomy: imaging evaluation. AJR Am J Roentgenol. 1992;158 (4): 785-9. AJR Am J Roentgenol (citation) - Pubmed citation
- 7. Haaga JR, Boll D. CT and MRI of the whole body. Mosby. (2009) ISBN:0323053750. Read it at Google Books - Find it at Amazon