AAV ANCA-associated vasculitis ACR American College of Rheumatology ADA adalimumab ANCA anti-neutrophil cytoplasmic antibody AZA azathioprine bDMARDs biologic disease-modifying anti-rheumatic drugs c-ANCA cytoplasmic ANCA CG cryoglobulin CHCC Chapel Hill Consensus Conference Cr creatinine CT computed tomography CRP C-reactive protein CyA cyclosporine CV cryoglobulinemic vasculitis CY cyclophosphamide DMARDs disease-modifying anti-rheumatic drugs * a The aorta and its primary branches corresond to the aorta (ascending, arch, thoracic descending, abdominal descending), primary branches of the aorta (including the coronary artery), and pulmonary artery. * b Multiple lesions are defined as those that involve two or more of the above arteries or sites or two or more segments of the aorta. * c Hypertrophic lesions are detected by ultrasonography (macaroni sign of the common carotid artery), contrast-enhanced CT, contrastenhanced MRI (circumferential contrast enhancement of the arterial wall), and PET-CT (circumferential FDG uptake of the arterial wall). * d Stenotic lesions and dilated lesions are detected by chest radiography (wave-like deformation of the descending aorta), CT angiography, MR angiography, echocardiography (aortic insufficiency), and angiography. They are accompanied by dilatation of the ascending aorta and frequently also by aortic insufficiency. In the chronic stage, circumferential calcification of the arterial wall is visualized by CT, and the development of collateral circulation is detected by CT angiography and MR angiography Points of attention in imaging diagnosis: Contrast-enhanced CT is performed in the late phase of contrast enhancement. CT angiography is performed in the early phase of contrast enhancement with 3-dimensional image processing. Angiography is usually performed when other procedures such as endovascular treatment and coronary artery angiography or left ventriculography are simultaneously intended. C. Conditions to be included in the differential diagnoses of Takayasu arteritis Arteriosclerosis, congenital vascular anomaly, inflammatory abdominal aortic aneurysm, infectious aneurysm, syphilitic mesaortitis, giant cell arteritis (temporal arteritis), vascular Behçet's disease, IgG4-related diseases. Definite: At least 1 of the items in A + any of the conditions in B are observed, and conditions in C can be excluded.