CT and MRI for identification and diagnosis of immunoglobulin G4 associated cholangitis

Abstract

Objective To investigate the computed tomography (CT) and magnetic resonance imaging (MRI) characteristics of immunoglobulin G4 associated cholangitis (IAC) and the key points for identification and diagnosis. Methods The clinical data of 11 patients with IAC who were admitted to the Peking University People's Hospital from January 2013 to January 2015 were retrospectively analyzed. Patients received plain and enhanced scan of CT, plain and enhanced scan of MRI and magnetic resonance cholangiopancreatography (MRCP) examination before hormone therapy. Patients were followed up by telephone interview and outpatient examination till January 2015, and their imaging data were evaluated. Results Of the 11 patients, 7 patients received plain and enhanced scan of CT, 6 patients received plain and enhanced scan of MRI and 7 patients received MRCP examination. The results of CT and MRI examinations showed bile duct segmental stricture and non-obliteration of cavity were detected in the 11 patients. Diffused thickening of intrahepatic and extrahepatic bile duct and no correlation between the thickening and the stricture of the bile duct was detected in the 8 patients. The bile duct wall of 3 patients was locally thickened, including 2 thickened common bile duct wall at the region of the head of the pancreas and 1 thickened hilar bile duct. The results of MRI showed low T2WI signal of the bile duct wall in 7 patients and equal signal in 4 patients. Enhanced signal in the bile duct wall was detected in the delayed phase in 11 patients by enhanced scan of CT and MRI, and 8 of the 11 patients had enhanced signal in the arterial, venal and delayed phase. Nine patients were complicated with autoimmune pancreatitis (3 of them were with concomitant renal disease) , and 1 patient was only complicated with immune-related renal disease. Enlargement of lymph nodes was detected around the pancreas in 3 patients, while no enlargement of lymph nodes was detected in 8 patients. Among all the 11 patients undergoing hormone therapy, 8 patients were followed up for a median time of 13 months (range, 6-18 months) , including 7 patients with good recovery and 1 patient with recurrence of IAC. Conclusion Diffused and irregular thickening and stenosis but not occlusion of biliary duct, the thickening and stenosis which are detected by CT and MRI examinations is relatively independent, and associated with autoimmune pancreatitis and other organs involved may be helpful to make a diagnosis of IAC. Key words: IgG4 associated cholangitis; X-ray computed tomography; Magnetic resonance imaging; Diagnosis