Autoimmune pancreatitis: whole-body 18F-FDG PET/CT findings

The study aimed to investigate the function of F-18-fluorodeoxyglucose positron emission tomography/computed tomography (F-18-FDG PET/CT) in diagnosing of autoimmune pancreatitis (AIP) and whole-body evaluation. Seven AIP patients who underwent F-18-FDG PET/CT systemic examination in our hospital from August 2010 to March 2012 were analyzed retrospectively. Systemic PET/CT routine scanning and pancreatic delayed scanning were performed in all patients. The mean age of 7 AIP patients (6 male and 1 female) was 54.2 years (range from 42 to 71 years). The pancreas showed diffuse enlargement in 6 cases, and segmental enlargement in 1 case. Fluorodeoxyglucose (FDG) uptake was increased in diseased region. The maximum standardized uptake value (SUVmax) was 4.38 +/- A 0.90 and increased to 5.31 +/- A 1.08 after delayed scanning, of which small amounts of inflammatory exudate around pancreas was observed in 4 cases. Extrapancreatic lesions (EPLs) were observed in all 7 cases: lymphadenectasis (n = 5), lymphadenectasis with increased FDG uptake (n = 4); associated sialosis with metabolism enlargement (n = 4); associated cholangitis (n = 4); associated interstitial pneumonia (n = 3); inverted "V" shaped high FDG uptake foci in prostate (n = 5). AIP is a systemic disease. F-18-FDG PET/CT can exhibit the characteristics of AIP pancreatic lesions, and also better reflect the changes and metabolic characteristics of extrapancreatic organs. It plays a distinct role in diagnosis, differentiating of AIP and whole-body evaluation.