Retrospective Study
Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Oct 28, 2016; 22(40): 8940-8948
Published online Oct 28, 2016. doi: 10.3748/wjg.v22.i40.8940
Ansa pancreatica as a predisposing factor for recurrent acute pancreatitis
Takana Yamakawa Hayashi, Wataru Gonoi, Takeharu Yoshikawa, Naoto Hayashi, Kuni Ohtomo
Takana Yamakawa Hayashi, Wataru Gonoi, Kuni Ohtomo, Department of Radiology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-8655, Japan
Takeharu Yoshikawa, Naoto Hayashi, Department of Computational Diagnostic Radiology and Preventive Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-8655, Japan
Author contributions: Hayashi YT and Gonoi W designed the research, analyzed data, and drafted the manuscript; Yoshikawa T, Hayashi N and Ohtomo K revised the manuscript; all authors have read and approved the final version to be published.
Supported by JSPS KAKENHI, No. 25870148.
Institutional review board statement: Based on the Declaration of Helsinki, the Research Ethics Committee of the University of Tokyo Hospital approved the prospective and retrospective use of the clinical, biochemical, and radiographic data for the present cross-sectional study.
Informed consent statement: Our institutional review board approved waiver of informed consent for the present cross-sectional study about the patient (pancreatitis) group. All of the subjects of community group provided written informed consent for the comprehensive epidemiological study.
Conflict-of-interest statement: None.
Data sharing statement: No additional data are available.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Wataru Gonoi, MD, PhD, Department of Radiology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo Bunkyo-ku, Tokyo 113-8655, Japan. watapi-tky@umin.net
Telephone: +81-358-008666 Fax: +81-358-008935
Received: June 14, 2016
Peer-review started: June 17, 2016
First decision: July 12, 2016
Revised: August 11, 2016
Accepted: September 14, 2016
Article in press: September 14, 2016
Published online: October 28, 2016
Abstract
AIM

To determine the non-biased prevalence and clinical significance of ansa pancreatica in patients with acute pancreatitis using magnetic resonance imaging (MRI).

METHODS

Our institutional review board approved this cross-sectional study, which consisted of a community-based cohort of 587 consecutive participants in a whole-body health-check program, and 73 subjects with episode of acute pancreatitis (55 patients with a single episode of acute pancreatitis, and 18 patients with recurrent acute pancreatitis). All of the subjects underwent abdominal MRI including magnetic resonance cholangiopancreatography, medical examinations, and blood tests. Two board-certified, diagnostic, abdominal radiologists evaluated the images, and ansa pancreatica was diagnosed based on its characteristic anatomy on MRI.

RESULTS

Compared with the community group [5/587 (0.85%)], patients with recurrent acute pancreatitis had a significantly higher frequency of ansa pancreatica [2/18 (11.1%)] (P = 0.016; OR = 14.3; 95%CI: 1.27-96.1), but not compared with patients with single-episode acute pancreatitis [1/55 (1.8%)] (P = 0.42; OR = 2.1; 95%CI: 0.44-19.7). Multiple logistic regression analysis using age, alcohol intake, presence of ansa pancreatica, and presence of autoimmune disease as independent covariates, revealed a significant relationship between the presence of ansa pancreatica and recurrent acute pancreatitis. The presence of autoimmune disease was also significantly associated with the onset of recurrent acute pancreatitis. On the other hand, neither age nor alcohol intake were significantly related to the onset of recurrent acute pancreatitis.

CONCLUSION

The present study is the first to provide robust evidence that the presence of ansa pancreatica is significantly associated with recurrent acute pancreatitis.

Keywords: Anatomy, Cholangiopancreatography, Pancreatitis, Magnetic resonance imaging, Pancreatic duct

Core tip: Ansa pancreatica is a rare anatomical variation of the accessory pancreatic duct and was hypothesized to be a predisposing factor for pancreatitis. However its in vivo prevalence was unknown and no case-control study has confirmed its clinical significance. This study is the first case-control study to determine the non-biased prevalence and provide robust evidence that the presence of ansa pancreatica is significantly associated with recurrent acute pancreatitis, using non-invasive magnetic resonance imaging.