Aim: To assess the spectrum of findings using multiphase contrast-enhanced computed tomography (CT) in patients with autoimmune pancreatitis (AIP).
Materials and methods: Fifty patients (four female and 46 male, mean age 65 years) were retrospectively identified from consecutive patients with abnormal CT findings of the pancreas and negative work-up for known causes. These patients had at least one finding supporting the diagnosis of AIP: serological abnormality, histopathological abnormality, or response to steroid. Two radiologists evaluated multiphase contrast-enhanced CT images in consensus.
Results: The pancreas showed diffuse enlargement (n=16; 32%), focal enlargement (n=18; 36%), or no enlargement (n=16; 32%). Forty-nine (98%) patients showed abnormal contrast enhancement in the affected pancreatic parenchyma, including hypoattenuation during the pancreatic phase (n=45; 90%) and hyperattenuation during the delayed phase (n=39; 87%). The following findings were also seen in the pancreas: a capsule-like rim (n=24; 48%); no visualization of the main pancreatic duct lumen (n=48; 96%); ductal enhancement (n=26; 52%); upstream dilatation of the main pancreatic duct (n=27; 54%); upstream atrophy of the pancreatic parenchyma (n=27; 54%); calcification (n=7; 14%); and cysts (n=5; 10%). Forty-two (84%) patients showed one or more of the following extrapancreatic findings: biliary duct or gallbladder abnormality (n=40; 80%); peripancreatic (n=8; 16%) or para-aortic (n=10; 20%) soft-tissue proliferation; and renal involvement (n=15; 30%).
Conclusion: Patients with AIP presented with a variety of CT findings in the pancreas and the extrapancreatic organs. The present study highlights pancreatic ductal enhancement in a subset of patients with AIP.