Role of MR and Scintigraphy in Detection of Biliary Leakage after Iatrogenic or Traumatic Injury

Abstract

Bile leak is best defined as a collection of bile in anunexpected location. The symptoms due to bile leak areoften vague and it is important to recognize them to decide an appropriate management approach. The consequence of bile leak depends upon its volume and location. A small-volume subhepatic bile leak causes fewer symptoms and may be managed conservatively.A large-volume hepatic subcapsular leak or a leak into the peritoneal cavity requires aggressive treatment. The principal causes of bile leak are intraoperative biliary injury, insufficiency of the bilioenteric anastomosis, and bile oozing from the transected liver surface. Most bile duct injuries occur as a result of cholecystectomy for symptomatic gallstone disease. Bile duct injuries following laparoscopic cholecystectomy are more prevalent than those following open cholecystectomy. There are the non-invasive but minimally specific investigations including sonography, CT, and on the other, on the other hand invasive investigations such as ERCP, which remain the gold standard techniques. The first group of techniques lack specificity as they usually show subhepatic or perianastomotic ‘‘collections’’. While the second group, and ERCP in particular, carry a risk of many complications, and they are still not of perfect sensitivity The standard MRC demonstrates indirect signs relating to the presence of effusion or perihepatic collections and these require careful interpretation in the post-transplant context, as they could be residual ascites, postoperative collections, or localised collections of bile (biloma). In contrast, hepatobiliary excretion demonstrates a direct sign (opacification of the bile ducts or collections). The value of gadolinium-based contrast agents with hepatobiliaryspecificity has been broadly proven in terms of identifying andcharacterizing hepatic lesions. DHBS, which has been introduced for detection of biliary leak in 1970s, has stood the test of time for detecting bile leak. IT is a physiologic, rapid, non-invasive, safe, simple procedure for the detection of presence, site and extent of the bile leak occurring due to various etiologies. This technique provides additional information about functional and morphological status of biliary tract as in the cases of trauma and transplanted liver. Due to low level of radiation exposure involved, it can be repeated and hence, isuseful in evaluating the response to medical or surgical treatment. However, sometimes it may not be possible to accurately characterize the location and extent of bile leaks on HBS, because of its poor anatomical resolution. SPECT/CTis an imaging modality thatprovides anatomic and functional information whichmuch more useful in such cases. SPECT/CT was found to be extremely useful in the characterization of the extent of abdominal collections, in defining the exact extent of intraparenchymal collections in the liver and for defining the contamination sites and to know whether they have any intra-abdominal connections.