title: Azygos continuation of inferior vena cava: CT appearance.
abstract: Two cases demonstrating the computed tomographic appearance of azygos continuation of the inferior vena cava (IVC) are presented. One is associated with a retroaortic left renal vein and the other with a duplicated IVC. An enlarged azygos vein should not be confused with retrocrural lymphadenopathy or a mediastinal mass. It is a tubular structure extending from the diaphragm to the azygos arch, which together with the aorta forms a characteristic collar around the trachea. It enhances intensely after intravenous injection of contrast material.
mesh_terms: D001401:Azygos Vein / Q000000981:diagnostic imaging*; D003937:Diagnosis, Differential; D004108:Dilatation, Pathologic; D006801:Humans; D008297:Male; D008875:Middle Aged; D010179:Pancreas / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed; D014652:Vascular Diseases / Q000000981:diagnostic imaging; D014682:Vena Cava, Inferior / Q000002:abnormalities* / Q000000981:diagnostic imaging