Stephanie A Lee-Felker1, Ely R Felker1, Barbara Kadell1, James Farrell2, Steven S Raman1, James Sayre3, David S Lu1. 1. 1 Department of Radiology, David Geffen School of Medicine at UCLA, Ronald Reagan UCLA Medical Center, 757 Westwood Plaza, Ste 1638, Los Angeles, CA 90095. 2. 2 Department of Medicine, Division of Digestive Diseases, Yale School of Medicine, New Haven, CT. 3. 3 Department of Biostatistics, UCLA School of Public Health, Los Angeles, CA.
Abstract
OBJECTIVE: The purposes of this study were to identify the most common imaging features of autoimmune pancreatitis and to evaluate the utility of MDCT for differentiating autoimmune pancreatitis from two more frequently encountered differential diagnoses--pancreatic ductal adenocarcinoma and acute interstitial pancreatitis. MATERIALS AND METHODS: Dual-phase contrast-enhanced MDCT images of 91 patients (39 with autoimmune pancreatitis, 25 with pancreatic ductal adenocarcinoma, 27 with acute interstitial pancreatitis) were evaluated by two radiologists in consensus for distribution of pancreatic abnormality, sausage shape, low-attenuation halo, pancreatic duct dilatation, peripancreatic stranding, lymphadenopathy, biliary abnormality, vascular involvement, and renal lesions. Chi-square tests, multiple logistic regression analysis, and ROC analysis were performed. RESULTS: The most common imaging features of autoimmune pancreatitis were sausage shape (25/39 [64%]) and low-attenuation halo (23/39 [59%]). Pancreatic duct dilatation (20/25 [80%]) and biliary dilatation (11/25 [44%]) were most frequent in pancreatic ductal adenocarcinoma. Peripancreatic stranding (22/27 [81%]) was most frequent in acute interstitial pancreatitis. Sausage shape, low-attenuation halo, and absence of a pancreatic duct or biliary dilatation differentiated autoimmune pancreatitis from pancreatic ductal adenocarcinoma with an accuracy of 0.88. Sausage shape and absence of peripancreatic stranding differentiated autoimmune pancreatitis from acute interstitial pancreatitis with an accuracy of 0.82. There was no significant difference in the frequency of vascular involvement or of lymphadenopathy among these diagnoses. CONCLUSION: Typical cases of autoimmune pancreatitis can be accurately differentiated from pancreatic ductal adenocarcinoma and acute interstitial pancreatitis on the basis of characteristic MDCT features. However, autoimmune pancreatitis should be considered in the presence of atypical features.
OBJECTIVE: The purposes of this study were to identify the most common imaging features of autoimmune pancreatitis and to evaluate the utility of MDCT for differentiating autoimmune pancreatitis from two more frequently encountered differential diagnoses--pancreatic ductal adenocarcinoma and acute interstitial pancreatitis. MATERIALS AND METHODS: Dual-phase contrast-enhanced MDCT images of 91 patients (39 with autoimmune pancreatitis, 25 with pancreatic ductal adenocarcinoma, 27 with acute interstitial pancreatitis) were evaluated by two radiologists in consensus for distribution of pancreatic abnormality, sausage shape, low-attenuation halo, pancreatic duct dilatation, peripancreatic stranding, lymphadenopathy, biliary abnormality, vascular involvement, and renal lesions. Chi-square tests, multiple logistic regression analysis, and ROC analysis were performed. RESULTS: The most common imaging features of autoimmune pancreatitis were sausage shape (25/39 [64%]) and low-attenuation halo (23/39 [59%]). Pancreatic duct dilatation (20/25 [80%]) and biliary dilatation (11/25 [44%]) were most frequent in pancreatic ductal adenocarcinoma. Peripancreatic stranding (22/27 [81%]) was most frequent in acute interstitial pancreatitis. Sausage shape, low-attenuation halo, and absence of a pancreatic duct or biliary dilatation differentiated autoimmune pancreatitis from pancreatic ductal adenocarcinoma with an accuracy of 0.88. Sausage shape and absence of peripancreatic stranding differentiated autoimmune pancreatitis from acute interstitial pancreatitis with an accuracy of 0.82. There was no significant difference in the frequency of vascular involvement or of lymphadenopathy among these diagnoses. CONCLUSION: Typical cases of autoimmune pancreatitis can be accurately differentiated from pancreatic ductal adenocarcinoma and acute interstitial pancreatitis on the basis of characteristic MDCT features. However, autoimmune pancreatitis should be considered in the presence of atypical features.