[Duplex ultrasound characterization of hepatic vein blood flow in healthy probands]

To characterise and standardise hepatic venous flow during the respiratory cycle in all three hepatic veins and to determine the most adequate measurement area within the vessel.

In 25 healthy subjects duplex Doppler measurements were performed of the right (RHV), middle (MHV) and left (LHV) hepatic vein. In full inspiration, mid-inspiration and expiration the maximum flow velocities of all three hepatic venous flow components (phase 1 to 3) were measured and a systolic to diastolic (S/D) ratio was determined.

In full inspiration there was a decrease of the maximum flow velocities compared to mid-inspiration (p = 0.0001). In expiration there was an increase of the maximum flow velocities (p = 0.0005). The maximum flow velocities of the MHV in mid-inspiration were -0.21 +/- 0.019 m/s (phase 1), -0.16 +/- 0.016 m/s (phase 2) and 0.08 +/- 0.011 m/s (phase 3). The S/D ratio decreases on inspiration and increases on expiration. The maximum flow velocities of the LHV differed significantly from those of the RHV and MHV. The measurements of the RHV and MHV were both reliable. Measurements from central to peripheral within the hepatic veins showed a decrease in maximum flow velocities.

For standardisation of hepatic venous flow measurements the respiratory state must be determined. The most adequate area for duplex Doppler ultrasound measurements is situated about one or two centimetres from the orifice of the vena cava.