Purpose: To assess the accuracy of time-of-flight MR Angiography (MRA) with bolus tracking in evaluating mean blood velocity and flowrate in the portal vein in patients with chronic hepatitis versus healthy volunteers.
Material and methods: Fifteen patients with clinically-defined post-viral chronic hepatitis (viruses B and C) were examined with bolus tracking MRA and color Doppler US to evaluate portal blood flow. Both examinations were performed before and after a 1500 kcal meal. We evaluated mean blood flow velocity and flowrate in the portal vein. MRA results were compared with color Doppler findings; the results in chronic hepatitis patients were compared with those of healthy volunteers.
Results: The correlation between mean portal blood velocity, as measured with MRA and color Doppler US, was r = .82 before and r = .79 after the meal. There was no significant difference in mean velocity between the chronic hepatitis patients and the healthy volunteers. The correlation between portal flowrate, as measured with MRA and color Doppler US, was r = .87 before and r = .91 after the meal. There was no significant difference in mean flowrate between the chronic hepatitis patients and the healthy volunteers. In contrast, there were significant differences in mean velocity and portal flowrate, as measured with MRA before the meal, between the chronic hepatitis patients and the healthy volunteers.
Discussion and conclusions: Bolus tracking MRA is superior to color Doppler US in quantitating blood flow in the portal vein and evaluating changes after a meal. Decreased mean velocity and flowrate may indicate impaired function, as it happens in early chronic hepatitis.