Impact of changing our cannulation method on the incidenceof post-endoscopic retrograde cholangiopancreatography pancreatitis after pancreatic guidewire placement

AIM： To clarify whether the incidence of post-endoscopic retrograde cholangiopancreatography （ERCP） pancreatitis （PEP） after pancreatic guidewire placement （PGW） can be reduced by using a different cannulation method. METHODS： BebNeen April 2001 and October 2009, PGW was performed in 142 patients with native papilla to overcome difficult biliary cannulation. Our cannulation method for ERCP was changed from contrast injection （CI） using a single-lumen catheter （April 2001-May 2008） to wire-guided cannulation （WGC） using a double-lumen catheter （June 2008-October 2009）. The CI protocol was also changed during the study period： in the first period it was used for routine pancreatography for detecting small pancreatic cancer （April 2001-November 2002）, whereas in the second period it was not （December 2002-May 2008）. In PGW with CI using a single- lumen catheter, the contrast medium in the catheter lumen was injected into the pancreatic duct. The success rate of biliary cannulation, the incidence of PEP according to the cannulation method, and the impact of CI using a single-lumen catheter on PEP in comparison with WGC using a double-lumen catheter were investigated.RESULTS： CI with routine pancreatography, CI without routine pancreatography, and WGC were performed in 27 patients, 77 patients and 38 patients, respectively. Routine pancreatography did not contribute to the early diagnosis of pancreatic cancer in our study period. In CI without routine pancreatography and WGC, diagnostic pancreatography was performed in 17 patients and no patients, respectively. The success rate of biliary cannulation by PGW alone was 69%, and the final success rate was increased to 80.3% by the addition of consecutive maneuvers or a second ERCP. PEP occurred in 22 patients （15.5%）, and the severity was mild in all cases. When analyzed according to cannulation method, the incidence of PEP was 37.0% （10/27） in the patients who underwent CI with routine pancreatography, 14.3% （11/77） in those who underwent CI without routine pancreatography, and 2.6% （1/38） in those who underwent WGC. In all patients who underwent CI using a singlelumen catheter, the incidence of PEP was 20% （21/104）, which was significantly higher than that in WGC using a double-lumen catheter. In univariate and multivariate analysis, CI using a single-lumen catheter showed a high, statistically significant, odds ratio for PEP after PGW. CONCLUSION： The practice of a cannulation method involving the use of a double-lumen catheter minimizes the CI dose administered to the pancreatic duct and reduces the incidence of PEP after PGW.

Growth process of small pancreatic carcinoma: A case report with imaging observation for 22 months

This report describes serial observations of the growth process of a small invasive ductal carcinoma (IDC) of the pancreas from imaging studies. Histopathological studies showed IDC with macroscopic retention cysts proximal to an intraductal papillary-mucinous adenoma with mild atypia of the branch duct type in the pancreatic body, with no relation between the two lesions. IDC was demonstrated as an extremely low-echoic mass resembling a cyst with an unclear margin on the initial endoscopic ultrasonography. We misinterpreted the low-echoic mass as a benign intraductal mucinous-papillary neoplasm (IPMN) based on findings of other imaging studies, and the patient was followed-up. The mass increased from 7 mm to 13 mm in diameter over 22 mo, and remained smaller than 10 mm in diameter for about 420 d. The tumor volume doubling time was 252 d. The Ki67 labeling index was 15.9%, similar to that described in previous reports. Hence, IDC may grow slowly while remaining small.