Gastrointestinal manifestations of systemic vasculitis and its mimickers: A multimodality imaging review

Gastrointestinal involvement in systemic vasculitis is uncommon and frequently manifests with nonspecific imaging findings, resulting in delayed diagnosis and significant morbidity. Early recognition is critical to prevent life-threatening complications such as bowel ischemia and perforation. Patients typically present with nonspecific symptoms, including abdominal pain, nausea, vomiting, diarrhea, weight loss, GI bleeding, and rarely, perforation. Imaging demonstrates key intestinal, vascular, and extraintestinal manifestations, including mural thickening, submucosal edema, mural hyperenhancement, vascular wall abnormalities, and solid organ infarcts. Diagnosis is established by correlating imaging findings with clinical and laboratory features and may require histopathological confirmation. There is considerable overlap in imaging features with infection, inflammatory bowel disease, and thromboembolic mesenteric ischemia may lead to underrecognition or delayed diagnosis of vasculitis. This review highlights bowel and associated abdominal vascular imaging findings across different systemic vasculitides, emphasizing key features that help differentiate them from its common mimickers.