Immunoglobulin G4-related Periaortitis and Periarteritis: CT Findings in 17 Patients

Purpose: To retrospectively evaluate computed tomographic (CT) findings of immunoglobulin G4 (IgG4)-related disease involving the vascular system. Materials and Methods: This study was approved by the institutional review board, and all patients included had consented to the use of their medical records for the purpose of research. The study consisted of 17 patients (16 men and one woman; age range, 54-86 years). CT findings of IgG4-related periarterial lesions were retrospectively analyzed. Radiopathologic correlations were examined on the basis of surgically resected specimens. Results: A total of 22 periarterial lesions were detected in 17 patients. The lesions were located in the thoracic aorta (n = 4), abdominal aorta to iliac arteries (n = 13), superior mesenteric artery (n = 3), inferior mesenteric artery (n = 1), and splenic artery (n = 1). Radiologically, they were characterized by arterial wall thickening (mean thickness, 11 mm), relatively clear circumscription, possible association with luminal change (mostly dilated and rarely stenotic), exaggerated atherosclerotic change, and homogeneous enhancement at the late phase of contrast material-enhanced CT. Twelve patients (71%) had IgG4-related disease in other organs. Pathologically, diffuse lymphoplasmacytic infiltration, numerous IgG4-positive plasma cells, and irregular fibrosis were noted in the thickened arterial wall, especially at the adventitia. Steroid therapy administered to eight patients rapidly diminished the arterial wall thickening. One patient who did not receive steroid therapy showed spontaneous improvement at follow-up CT. Conclusion: IgG4-related arterial lesions occur mainly in the aorta and its main branches and are radiologically characterized by homogeneous arterial wall thickening corresponding to pathologic features of IgG4-related sclerosing inflammation in the adventitia. (C) RSNA, 2011