Anatomical Variations of Gall bladder and Bile ducts-An MRI study

Abstract

Introduction: The Anatomy of the biliary tree is complex and is characterized by the frequent presence of Anatomical variations which can be found in ~50% of the general population. Accurate knowledge of the bile duct system anatomy is critical to properly diagnose hepatobiliary pathologies and minimize postoperative complications. Methods: This was a cross-sectional study at the Kampala MRI Centre. This study involved a retrospective analysis of Magnetic Resonance Cholangio-Pancreatography images of patients investigated from January 2017 to December 2022. Results: Out of the 231 patient MRCP images, we found out that the majority (57%) were female. In addition, the majority (43.3%) were 51 years and above. The commonest Gallbladder shape observed was the pear shape in 56.3% of cases. External gallbladder variations included Phrygian cap (16.5%) and Hartman pouch in 11.3% of the cases. All patients (231) had sub hepatic gallbladders. The majority of patients (53.2%) had the typical cystic duct course and insertion with a high entry in 24.2%, low entry in 18.2%, and medial entry in 4.4% of the cases. A majority 118 (51%) of the patients had Type 1 variation of intrahepatic ducts, 29.9% had type A2, 14.7% had type A3, 4% had type A5 while less than 1% had a very rare type of variation. Furthermore, this study showed that the mean Common Bile Duct (CBD) diameter was 4.7mm, the standard deviation was 1.4mm and a range of (1.6-8.5) mm. It was noted that for every unit increase in the average age, there is an increase in the average CBD diameter.