The inferior vena cava, or IVC, is the largest vein in the body, collecting deoxygenated blood from the lower extremities, pelvis, and abdomen and returning it to the right atrium of the heart. On ultrasound, the IVC is routinely evaluated during abdominal examinations and echocardiography. In echocardiography, the IVC diameter and its respiratory variation are used to estimate right atrial pressure: a normal IVC collapses more than 50 percent with a sniff, while a distended IVC that does not collapse suggests elevated right heart pressures. Abnormalities of the IVC include thrombosis, tumor invasion from renal cell carcinoma, and congenital anomalies like IVC duplication.
Sonography Term