Dynamic measurements of total hepatic blood flow with Phase Contrast MRI

Abstract

Background/Aims To measure total hepatic blood flow including portal and proper hepatic artery flows as well as the temporal evolution of the vessel's section during a cardiac cycle. Methods Twenty healthy subjects, with a mean age of 26 years, were explored. Magnetic resonance imaging blood flow measurements were carried out in the portal vein and the proper hepatic artery. MR studies were performed using a 1.5T imager (General Electric Medical Systems). Gradient-echo 2D Fast Cine Phase Contrast sequences were used with both cardiac and respiratory gatings. Data analysis was performed using a semi-automatic software built in our laboratory. Results The total hepatic flow rate measured was 1.35 ± 0.18 L/min or 19.7 ± 4.6 mL/(min kg). The proper hepatic artery provided 19.1% of the total hepatic blood flow entering the liver. Those measurements were in agreement with earlier studies using direct measurements. Mean and maximum velocities were also assessed and a discrepancy between our values and the literature's Doppler data was found. Measurements of the portal vein area have shown a mean variation, defined as a “pulsatility” index of 18% over a cardiac cycle. Conclusions We report here proper hepatic artery blood flow rate measurements using MRI . Associated with portal flow measurements, we have shown the feasibility of total hepatic flowmetry using a non-invasive and harmless technique.