Azygos venous blood flow: measurement with direct bolus imaging.

Abstract

To evaluate a magnetic resonance (MR) imaging technique for measurement of azygos blood flow volume, which is an important indicator of superior collateral circulation in patients with portal hypertension. Azygos blood flow was measured by means of direct bolus (DB) imaging, an MR flow measurement technique. A presaturation pulse was applied in combination with electrocardiographic gating. The measured flow volume was 320 mL/min +/- 30 (mean +/- standard error of mean) in the control subjects, 550 mL/min +/- 130 in patients with cirrhosis of the liver and without varices, and 660 mL/min +/- 60 in patients with cirrhosis of the liver and with varices. The flow volume was significantly higher in each of the groups with cirrhosis of the liver than in the control group (P < .01). Furthermore, a significant correlation was shown between DB imaging and continuous thermodilution measurements (r = .707, P < .01). DB imaging, which is noninvasive, was useful in the monitoring of the effect of treatment and in determination of the prognosis in patients with portal hypertension.