Portal vein blood flow was significantly higher in patients with hematological disease than in normal volunteers (31.2 +/- 15.5 ml/min.kg vs. 14.2 +/- 4.6 ml/min.kg;p < 0.01). In 81.8% of patients with hepatic infiltrates, fibrosis or both and increased portal vein blood flow, the hepatic vein pressure gradient was greater than 6 mm Hg..