Positron Emission Tomography with F-18 Fluorodeoxyglucose

Positron emission tomography (PET) with 18F fluorodeoxyglucose (FDG) is an effective method for screening throughout the entire body for organ lesions associated with IgG4-related disease (IgG4-RD). FDG, a tracer of glucose metabolism, accumulates in areas of active inflammatory changes, which are associated with enhanced glucose metabolism. In IgG4-RD, abnormal accumulation can be detected in type 1 autoimmune pancreatitis (AIP), salivary and lacrimal gland lesions, retroperitoneal fibrosis, nephritis, and other areas of high activity, all reflective of pathological changes occurring in this condition. It is also anticipated that this imaging modality will be a useful approach to the assessment of responses to treatment. Although there are still few systematic reports on PET examinations in IgG4-RD, we outline here some representative cases in which it was found useful, and consider its role in this disease.