Hilar and Pancreatic Gallium-67 Accumulation is Characteristic Feature of Autoimmune Pancreatitis

Introduction and Aims Autoimmune pancreatitis is characterized by severe lymphocytic inflammation, suggesting that gallium-67 scintigraphy provides a useful tool for detecting characteristic lesions of this disease, because gallium-67 concentrates in lymphoid cells. We tried to determine whether gallium-67 accumulates in the characteristic lesions. Methodology We performed gallium-67 scintigraphy in 24 patients with autoimmune pancreatitis before and after 4 weeks of corticosteroid therapy and determined the factors associated with positive images. Results Sixteen patients (67%) had marked gallium-67 accumulation in the pancreas before corticosteroid therapy and negative images after 4 weeks of therapy, and they had significantly higher serum IgG4 values than did those without gallium-67 accumulation (median, 758 mg/dL versus 329 mg/dL; p = 0.011). Marked hilar gallium-67 accumulation was found in 16 patients (67%) and was also associated with significantly higher serum IgG4 values than did those without it (median, 758 versus 239 mg/dL; p = 0.0044). Among 16 patients with positive hilar images, 12 had positive pancreatic uptake and 5 had both pancreatic and salivary gland uptakes. Conclusions Hilar and pancreatic accumulation of gallium-67 is a characteristic feature of autoimmune pancreatitis during the active stage of the disease, when IgG4 serum levels are high.