Auxiliary Value of Contrast‐Enhanced Ultrasound in the Assessment of <scp>IgG4</scp> ‐Related Disease Involving Superior Mesenteric Arterial Disease: A Case Report

ABSTRACT As a chronic disease characterized by progressive inflammation and fibrosis, IgG4‐related disease (immunoglobulin‐G4 related disease, IgG4‐RD) rarely involves the retroperitoneum. Early diagnosis and evaluation are vital for IgG4‐RD patients. Herein, we report on an elderly male patient diagnosed with IgG4‐RD, with superior mesenteric artery involvement. Combining the patient's clinical history, serology, imaging features, and excluding other suspected diseases, this patient was provisionally diagnosed as IgG4‐related disease involving the superior mesenteric artery. Before and after medication, contrast‐enhanced ultrasound was used to adjunctively assess whether fibrotic lesions around the superior mesenteric artery were in active phase to aid in drug efficacy assessment.