The hepatic veins are the three major veins, right, middle, and left, that drain blood from the liver directly into the inferior vena cava. On ultrasound, the hepatic veins are important landmarks that help identify the liver segments and are routinely evaluated with Doppler to assess their patency and flow patterns. The normal hepatic vein waveform is triphasic, reflecting the variations in pressure transmitted from the right atrium through the cardiac cycle. Loss of this normal triphasic pattern and development of a monophasic or flattened waveform can indicate liver disease, particularly cirrhosis or hepatic venous outflow obstruction such as Budd-Chiari syndrome.
Sonography Term