NONINVASIVE MEASUREMENT OF AZYGOS VENOUS-BLOOD FLOW USING MAGNETIC-RESONANCE

Monitoring treatment efficacy in patients with portal venous hypertens ion has been limited by the difficulty of direct or indirect assessmen t of portal vein pressure. The majority of currently available haemody namic tests, such as hepatic vein wedge pressure or azygos vein flow m easurement by thermodilution catheter, are invasive which has restrict ed their application. We describe a non-invasive cine phase contrast m agnetic resonance technique for quantitative measurements of bulk volu me flow and for demonstrating flow changes during the cardiac cycle in the azygos vein. The technique was used to analyse the azygos vein fl ow in seven adult volunteers and five patients with biopsy-confirmed c hronic liver disease, portal hypertension and endoscopically proven oe sophageal varices. In the volunteers the mean volume flow rates varied between 81 and 241 ml/min with a mean for the group of 171 ml/min, Th e patients had a significantly higher mean volume flow rate of 628 ml/ min (p<0.01), with a range of 339 to 945 ml/min, These preliminary res ults suggest that cine phase contrast magnetic resonance angiography i s a practical non-invasive method for measuring absolute azygos vein f low, and may provide a non-invasive method of monitoring portal hypert ension.