Evaluation of Intrahepatic Bile Duct Variations in Magnetic Resonance Cholangiopancreatography

Abstract

Introduction: A detailed knowledge of normal branching pattern of intrahepatic bile duct and their variations is of utmost importance for any liver or biliary tract surgery to avoid severe post-surgery complications and morbidity. The objective of this study was to evaluate variations of intrahepatic bile ducts in Magnetic Resonance Cholangiopancreatography (MRCP) examinations in Nepalese population.Methods: This quantitative, cross sectional study was performed in patients referred for MRCP examinations for various clinical indications to Tribhuvan University Teaching Hospital, Maharajgunj, Nepal. Data were collected for a period of four months from August to November 2019 after IRB approval. Convenience sampling was employed and a total of 90 examinations were included. Data were obtained from the 1.5T Magnetom Amira Siemens MRI scanner. The 3D MRCP images were visually analyzed and classified into 7 Types according to the classification given by Choi et al.Results: In our study 47.8% patients had Type 1/normal IHBD (n=43). 20% had Type 2 (n=18), 3.3% had Type 3A (n=3), 5.6% had Type 3B. Type 5A (n=5), 7.8% had 5B (n=7), 3.3% had Type 6 (n=3) and 6.7% had Type 7 (n=6). No patients were found to have Type 3C and Type 4 IHBD variation. Among the total number of Type 1 cases, 67.44% (n=29) were female and rest were male.Conclusions: Typical IHBD was only found in a 47.8% patients and common other variations were also noted in our population. Type 2 and Type 5B were found in 20% and 7.8% patients respectively.

Atypical Pattern of the Intrahepatic Biliary Duct on Magnetic Resonance Cholangiopancreatography in a Tertiary Care Centre: A Descriptive Cross-sectional Study

“…8 The atypical pattern of IHD was present in 24.12% which is less than the studies conducted in different parts of Nepal. 8,9 Among the atypical variations triple confluence (type 2) was the most common pattern which was followed by the type 3A pattern. Likewise, a study among the South Indian population and the Iranian population documented similar findings.…”

“…13 In this pattern of triple confluence, RHD is absent and possesses two or more orifices of RAPD, RPHD, and LHD in the plane of transection of the liver graft. 9 Thus, during liver transplantation, biliary reconstruction of these variants is complicated and technically difficult as it requires multiple anastomoses. 14 Other clinically relevant anatomic variants in which the RPHD drains into the LHD (type 3A) were present in 22.92% of the images.…”

“… 8 The atypical pattern of IHD was present in 24.12% which is less than the studies conducted in different parts of Nepal. 8 , 9 …”

“… 10 Nonetheless, another study among the Nepalese population revealed this variant only in 3.3% of cases. 9 In this variant, RPHD may be inadvertently ligated during left hepatectomy which may produce biliary cirrhosis of segments VI and VII. 15 A cadaveric study in Athens has reported aberrant insertion of RPHD into the CHD (type 3B) in 2.74%.…”

“… 5 However, a study reported the absence of type 3C variation. 9 The low insertion of RPHD into CHD (type 3B) and cystic duct (type 3C) variations increase the risk of damage to RPHD during laparoscopic procedures. 6 This aberrant duct may undergo accidental transection or ligation, subsequently leading to bile leakage or obstruction of segments VI and VII.…”