Utility of FDG-PET/CT in the diagnosis of IgG4-related diseases.

Objective The purpose of this work is to evaluate the usefulness of F-18-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) imaging in management of IgG4-related disease (IgG4-RD) by retrospective analysis of PET/CT results in IgG4-RD patients. Methods Twenty-six patients diagnosed with IgG4-RD according to Japanese diagnostic criteria who underwent F-18-FDG-PET/CT scans in the PLA General Hospital from January 2010 to May 2015 were enrolled in the study. Their clinical presentations and F-18-FDG-PET/CT findings were analysed. Results A total of 26 patients (20 men; 6 women) with a mean age of 53.8 years (range 35-71 years) and mean treatment course of 7.1 months (range 0.33-72 months) who underwent F-18-FDG-PET/CT scans were analysed. CRP was relatively low in all patients (mean 0.79 mgldl). F-18-FDG-PET/CT images confirmed that two or more organs were involved in all patients, and average SUV values for involved organs was 4.14 (range 0.30-8.78). Eleven patients were misdiagnosed with submandibular tumours, pancreatic cancer, pancreatitis, pulmonary interstitial fibrosis, retroperitoneal fibrosis or systemic vasculitis prior to F-18-FDG-PET/CT imaging. Conclusion F-18-FDG-PET/CT imaging is a useful tool for the differential diagnosis of IgG4-RD, and for mapping involved organs, guiding biopsy, and monitoring treatment response.