Anatomic variations of the pancreatic duct and their relevance with the Cambridge classification system: MRCP findings of 1158 consecutive patients

Abstract

Background: The study was conducted to evaluate the frequencies of the anatomic variations and the gender distributions of these variations of the pancreatic duct and their relevance with the Cambridge classification system as morphological sign of chronic pancreatitis using magnetic resonance cholangiopancreatography (MRCP).

Patients and methods: We retrospectively reviewed 1312 consecutive patients who referred to our department for MRCP between January 2013 and August 2015. We excluded 154 patients from the study because of less than optimal results due to imaging limitations or a history of surgery on pancreas. Finally a total of 1158 patients were included in the study.

Results: Among the 1158 patients included in the study, 54 (4.6%) patients showed pancreas divisum, 13 patients (1.2%) were defined as ansa pancreatica. When we evaluated the course of the pancreatic duct, we found the prevalence 62.5% for descending, 30% for sigmoid, 5.5% for vertical and 2% for loop. The most commonly observed pancreatic duct configuration was Type 3 in 528 patients (45.6%) where 521 patients (45%) had Type 1 configuration.

Conclusions: Vertical course (p = 0.004) and Type 2 (p = 0.03) configuration of pancreatic duct were more frequent in females than males. There were no statistically significant differences between the gender for the other pancreatic duct variations such as pancreas divisium, ansa pancreatica and course types other than vertical course (p > 0.05 for all). Variants of pancreas divisum and normal pancreatic duct variants were not associated with morphologic findings of chronic pancreatitis by using the Cambridge classification system. The ansa pancreatica is a rare type of anatomical variation of the pancreatic duct, which might be considered as a predisposing factor to the onset of idiopathic pancreatitis.

Keywords: magnetic resonance cholangiopancreatography; magnetic resonance imaging; pancreas divisum; pancreatic duct variants.

Figure 1

Descending course of pancreatic duct in 60 year of woman who had cholecystectomy. There is a Type 3b variation (the right posterior duct drained into the main hepatic duct) at the level of bifurcation of the biliary ducts and mild forms of renal pelvis dilatation.

Figure 2

Sigmoid course of pancreatic duct in 49 year-old woman with and trifurcation at the level of bifurcation of the biliary ducts (*): Sigmoid course of the pancreatic duct, (**): choledocholithiasis.

Figure 3

Vertical course (*) of pancreatic duct in 55 year-old woman who had cholecystectomy.

Figure 4

Loop course (*) of pancreatic duct in in 38 year-old woman with choledocholithiasis (**).

Figure 5

Variations in the configuration of the pancreas duct. Type 1: Bifid configuration with dominant duct of Wirsung, Type 2: Bifid configuration with dominant duct of Santorini without divisum, Type 3: Rudimentary non-draining duct of Santorini, Type 4: Pancreas divisum, Type 5: Ansa pancreatica.