Computed tomography and magnetic resonance imaging features of IgG4-related pancreatitis / 中华消化外科杂志

ABSTRACT

Objective To summarize the computed tomography (CT) and magnetic resonance imaging (MRI) features of IgG4-related pancreatitis.Methods The retrospective and descriptive study was conducted.The clinical data of 23 patients with IgG4-associated pancreatitis who were admitted to Sir Run Run Shaw Hospital of Zhejiang University School of Medicine from November 2012 to May 2018 were collected.There were 21 males and 2 females,aged from 45 to 83 years,with an average age of 63 years.Patients underwent upper abdominal enhanced CT and enhanced MRI examinations.Observation indicators(1) imaging examination of the patients;(2) imaging characteristics on CT and MRI examinations;(3) follow-up.Follow-up using outpatient examination including laboratory and imaging examination was performed to detect clinical symptoms and signs once a month within 3 months postoperatively,once every 3 months within 3 months to 1 year postoperatively,once every 6 months with 1-2 years postoperatively,and once a year after 2 years postoperatively up to August 2018.Measurement data with skewed distribution were represented as M (range).Count data were described as absolute numbers.Results (1) Imaging examination of the patients19 of 23 patients underwent upper abdominal enhanced CT combined with upper abdominal enhanced MRI scanning,3 underwent upper abdominal enhanced CT combined with upper abdominal MRI plain scanning,and 1 underwent only upper abdominal enhanced MRI scanning.(2) Imaging characteristics on CT and MRI examinationspancreatic manifestations included 7 aspects.① Location of lesion and morphological classificationof 23 patients,17 were diffuse type,showing sausage-like appearance;4 were focal type,including 2 with mass in the pancreatic head and 2 with mass in the pancreatic body and tail;2 were multiple type,including 1 with mass in the pancreatic head,body and tail,and 1 with mass in the pancreatic body and tail.② Density of lesions on CT examinationof 23 patients,22 received CT plain scanning,including 10 with equal density and 12 with slightly low density;1 didn't receive CT plain scanning.③ Signal of lesions on MRI examinationon T1 weighted imaging,16 of 23 patients showed homogeneous slightly low signal,4 showed isointensity signal,2 showed mixed slightly low signal,and 1 showed slightly high signal.On T2 weighted imaging,21 of 23 patients showed homogeneous slightly high signal,1 showed isointensity signal,and 1 showed mixed slightly high signal.Of 23 patients,19 underwent diffuse weighted imaging (DWI) and 4 didn't undergo DWI.There were 17 patients with slightly high signal and 2 with high signal on DWI.On apparent diffusion coefficient imaging,10 patients showed slightly low signal,and 9 showed low signal intensity.④ Calcificationof 23 patients,2 had multiple calcifications including 1 of diffuse type with calcification located at pancreatic head,and 1 of focal type with calcification located at pancreatic body and tail;20 had no calcification;1 without CT plain scanning cannot be judged calcification.⑤ Enhancement pattern23 patients showed progressive delayed enhancement of pancreatic lesions on enhancement scanning,homogeneous or heterogeneous enhancement in the arterial phase,and further enhancement in the portal venous phase and delayed phase (enhancement degree of focal type and multiple type was basically consistent with that of normal pancreas).⑥ Halo sign surrounding lesionsof 23 patients,7 had no halo sign,including 2 of diffuse type,3 of focal type,and 2 of multiple type;16 had halo sign (15 of diffuse type and 1 of focal type),including 11 with halo sign surrounding pancreatic body and tail,3 with halo sign surrounding whole pancreas,and 1 with halo sign posterior pancreatic body and tail,and 1 with halo sign anterior pancreatic head.⑦ The main pancreatic duct14 of 23 patients had irregular stenosis of the main pancreatic duct,7 had mild dilatation of the main pancreatic duct,and 2 had no dilatation of the main pancreatic duct.Extra-pancreatic manifestations included 3 aspects.① Bile duct dilatation10 of 23 patients had simple intra-hepatic and extra-hepatic bile duct dilatation,8 had no intrahepatic or extra-hepatic bile duct dilatation,and 5 had intra-pancreatic common duct stenosis with upstream bile duct dilatation.② Extra-pancreatic organ involvement18 of 23 patients had extra-pancreatic organ involvement (5 with gall bladder involvement,4 with intra-hepatic and extra-hepatic bile duct and gall bladder involvement,3 with intra-hepatic and extra-hepatic bile duct involvement,1 with lung involvement,1 with spleen involvement,1 with common duct involvement,1 with kidney involvement,1 with lung and intra-hepatic and extra-hepatic bile duct involvement,1 with fibrosis of mesenteric root),and 5 had no extra-pancreatic organ involvement.③ Retroperitoneal lymph nodes2 of 23 patients had enlarged retroperitoneal lymph nodes,21 had no enlarged retroperitoneal lymph nodes.(3) Follow-upof 23 patients,19 were followed up for 3-74 months,with a median time of 22 months.Sixteen of 19 patients had various degrees of improvement in clinical symptoms,laboratory and imaging manifestations after standardized hormonotherapy,and 3 had no response to hormonotherapy.Conclusions CT and MRI examinations have important diagnostic value for IgG4-related pancreatitis.The pancreas mainly show diffuse swelling and halo sign surrounding lesions is a typical imaging characteristic.