Association between anatomic variations of extrahepatic and intrahepatic bile ducts: Do look up!

Abstract

Biliary anatomic variations are usually asymptomatic, but they may cause problems in diagnostic investigations and interventional and surgical procedures, increasing both their technical difficulty and their postoperative complication rates. The aim of the present study was to evaluate the prevalence of anatomic variations in the intrahepatic biliary ducts (IHBD) in relation to demographical and clinical characteristics in a large study population requiring magnetic resonance cholangiopancreatography (MRCP) for various clinical conditions. The possible association between IHBD and extrahepatic biliary ducts (EHBD) variants was then explored. From January 2017 to May 2019, 1004 patients underwent MRCP. Demographical and clinical data were collected. IHBD and EHBD anatomy were recorded and the EHBD anatomy was classified using both qualitative and quantitative classifications. The presence of a type 3 EHBD variant (an abnormal proximal cystic duct [CD] insertion) in both qualitative and quantitative classifications and an intrapancreatic CD were associated with the presence of IHBD variants at univariate analysis (p = 0.008, p = 0.019, and p = 0.001, respectively). The presence of a posterior or medial insertion of the CD into the EHBD was a strong predictive factor of the presence of IHBD variants both at uni-and multivariate analysis (p = 0.002 and p = 0.003 for posterior insertion and p = 0.002 and p = 0.002 for medial insertion, respectively). The presence of gallstones on MRCP resulted in a strong predictor of the presence of an anatomical variant of the IHBD both at uni-and multivariate analysis (p = 0.027 and p = 0.046, respectively). In conclusion, the presence of a type 3 variant of the EHBD, an intrapancreatic CD and, especially, a posterior/medial CD insertion into the EHBD represent predictive factors of the concomitant presence of IHBD variants, thus radiologists must be vigilant when encountering these EHBD configurations and always remember to "look up" at the IHBD.Finally, the presence of an IHBD variant is a strong predictive factor of gallstones.

An exceedingly rare case of separated drainage of the cystic duct, the common bile duct and the main pancreatic duct documented on magnetic resonance cholangiopancreatography

“…Moreover, MRCP is quick, is not associated with radiation exposure and does not require the administration of contrast media, needing only a simple glass of juice to evaluate the anatomy of both the intra-and extrahepatic biliary ducts [9]. Finally, it allows the synchronous evaluation of the IHBD, whose anatomical variations are often associated with variations of the downstream biliary system, as was demonstrated also in the present case [7].…”

“…Moreover, since the EHBD and the IHBD maintain luminal continuity from the very start of organogenesis, it cannot be excluded that variations in the con guration of one system may induce or, at least, contribute to a concomitant alteration in the other system, causing some sort of "ripple effect" on the following morphogenetic phases. Nonetheless, recent evidence seems to support welldistinct mechanisms regulating the development of both the EHBD and the IHBD systems, suggesting that the molecular pathways involved in the development of the EHBD are more closely related to the formation of the duodenum and the pancreas [7]. Therefore, further studies are warranted to elucidate the mechanisms responsible for variations in the remodeling process of the biliary system during embryogenesis.…”

Case report: Rare benign obstructive disease of the biliary tract—a rare case of eosinophilic cholangitis

“…Compared to CT, US, and MRI, which lack radiation advantages, these imaging modalities are valuable for detecting lesions and managing the disease course of EC patients ( 11 , 12 ). In particular, MRCP serves as a gold standard for diagnosing and preoperatively evaluating biliary tract diseases due to its non-invasive characteristic, convenience, and high repeatability ( 13 , 14 ). In this case, a US examination revealed mild bile duct dilation, absence of calculi and tumor signs, but no inflammatory exudation surrounding the bile duct.…”

Towards a Simplified and Cost-Effective Diagnostic Algorithm for the Surveillance of Intraductal Papillary Mucinous Neoplasms (IPMNs): Can We Save Contrast for Later?

“…In particular, an enhancing mural nodule ≥5 mm is considered a “high-risk stigma” and thus requires surgical resection, whereas an enhancing nodule <5 mm and an enhancing thickened wall are regarded as “worrisome features” and should mandate further evaluation with EUS before intervention. Due to the clinical relevance of these radiological findings, and particularly the importance of discriminating between neoplastic solid components and mucus plugs or debris [ 40 ], gadolinium-enhanced MRI with magnetic resonance cholangiopancreatography (MRCP) has been widely recommended by IAP as the procedure of choice for evaluating a pancreatic cyst, based on superior contrast resolution as well as the advantage of avoiding radiation exposure [ 10 , 41 , 42 ]. Consequently, it is not surprising that the majority of radiologists (70%) support the routine use of intravenous contrast for the characterization and follow-up of incidental pancreatic cystic lesions in clinical practice, as testified by a survey distributed by the Society of Abdominal Radiology Disease Focused Panel [ 32 ].…”