CT findings in autoimmune pancreatitis: assessment using multiphase contrast-enhanced multisection CT
Received 29 March 2010; received in revised form 12 May 2010; accepted 2 June 2010. published online 12 July 2010.
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.
aDepartment of Radiology, Nagoya University Graduate School of Medicine, Nagoya, Japan
bDepartment of Radiology, Nagoya Hirokoji Clinic, Nagoya, Japan
cDepartments of Medical Technology, Nagoya University School of Health Science, Nagoya, Japan
Guarantor and correspondent: K. Suzuki, Department of Radiology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Shouwa-ku, Nagoya, Japan. 466-8550, Japan. Tel.: +81 52 744 2327; fax: +82 52 744 2335.
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