Meandering main pancreatic duct as a relevant factor to the onset of idiopathic recurrent acute pancreatitis.
BACKGROUND
Meandering main pancreatic duct (MMPD), which comprises loop type and reverse-Z type main pancreatic duct (MPD), has long been discussed its relation to pancreatitis. However, no previous study has investigated its clinical significance. We aimed to determine the non-biased prevalence and the effect of MMPD on idiopathic pancreatitis using non-invasive magnetic resonance (MR) technique.


RESULTS
A cross-sectional study performed in a tertiary referral center. The study enrolled 504 subjects from the community and 30 patients with idiopathic pancreatitis (7 acute, 13 chronic, and 10 recurrent acute). All subjects underwent MR scanning and medical examination. MMPD was diagnosed when the MPD in the head of pancreas formed two or more extrema in the horizontal direction on coronal images of MR cholangiopancreatography, making a loop or a reverse-Z shaped hairpin curves and not accompanied by other pancreatic ductal anomaly. Statistical comparison was made among groups on the rate of MMPD including loop and reverse-Z subtypes, MR findings, and clinical features. The rate of MMPD was significantly higher for all idiopathic pancreatitis/idiopathic recurrent acute pancreatitis (RAP) (20%/40%; P<0.001/0.0001; odds ratio (OR), 11.1/29.0) than in the community (2.2%) but was not higher for acute/chronic pancreatitis (14%/8%; P = 0.154/0.266). Multiple logistic regression analysis revealed MMPD to be a significant factor that induces pancreatitis/RAP (P<0.0001/0.0001; OR, 4.01/26.2). Loop/reverse-Z subtypes were found more frequently in idiopathic RAP subgroup (20%/20%; P = 0.009/0.007; OR, 20.2/24.2) than in the community (1.2%/1.0%). The other clinical and radiographic features were shown not associated with the onset of pancreatitis.


CONCLUSIONS
MMPD is a common anatomical variant and might be a relevant factor to the onset of idiopathic RAP.
Department of Radiology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan. watapi-tky@umin.net
Wataru
W
Gonoi
Hiroyuki
H
Akai
Kazuchika
K
Hagiwara
Masaaki
M
Akahane
Naoto
N
Hayashi
Eriko
E
Maeda
Takeharu
T
Yoshikawa
Shigeru
S
Kiryu
Minoru
M
Tada
Kansei
K
Uno
Hiroshi
H
Ohtsu
Naoki
N
Okura
Kazuhiko
K
Koike
Kuni
K
Ohtomo
D000208:Acute Disease; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010179:Pancreas / Q000002:abnormalities / Q000473:pathology; D010183:Pancreatic Ducts / Q000002:abnormalities* / Q000473:pathology*; D010195:Pancreatitis / Q000453:epidemiology* / Q000473:pathology*; D050500:Pancreatitis, Chronic / Q000453:epidemiology / Q000473:pathology