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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: To evaluate the performance of multidetector computed tomographic angiography (MDCTA) in assessing the surgical resectability of pancreatic head adenocarcinoma., Methods: With institutional review board approval, radiographic, surgical, and pathological records of 203 consecutive patients with adenocarcinoma of the pancreatic head were analyzed retrospectively. Patients were imaged with MDCT scanners using our institution's CTA pancreatic protocol. Images were compared with surgical outcomes to determine the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of MDCTA in determining resectability., Results: Data were analyzed twice, once with equivocal findings on MDCTA assumed as resectable and again with equivocal cases assumed as unresectable. All equivocal cases were ultimately unresectable; when this was assumed, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were determined to be 100%, 71%, 85%,100% and 89%. Twelve patients deemed resectable by preoperative MDCTA were found to be unresectable on surgical exploration owing to vascular involvement (n = 4), liver metastases (n = 4), and peritoneal involvement (n = 4)., Conclusions: Multidetector CT angiography offers accurate and valuable preoperative assessment of surgical resectability of pancreatic ductal adenocarcinoma. Liver and peritoneal metastases and vascular invasion still remain important pitfalls in preoperative evaluation.