In order to assess the validity of quantitative duplex Doppler measurements of portal vein How, 10 patients with proven diffuse liver disease and portal hypertension were examined serially by two independent observers over a 3 month period. Multiple measurements of the portal vein were made using a consistent technique in an attempt to minimize observer errors. One patient proved unsuitable for ultrasound examination. In the remaining nine patients the intra-observer portal vein measurements for one observer (19 paired examinations) correlated significantly for flow velocity (r = 0.80, P < 0.001) and derived bulk flow (r = 0.54, P < 0.02) but not for cross-sectional area (r = 0.27, P > 0.05). The intra-observer measurements for the second observer (11 paired examinations) were significantly correlated for cross-sectional area (r = 0.64, P < 0.05) and derived bulk flow (r = 0.61, P < 0.05) but not for flow velocity (r = 0.5, P > 0.05). The inter-observer measurements (28 paired examinations) of the portal vein were all highly significantly correlated for cross-sectional area (r = 0.63, P < 0.001), flow velocity (r = 0.79, P < 0.001) and derived bulk flow (r = 0.73, P < 0.001). These results suggest that this quantitative Doppler technique may be valid for the serial study of portal vein flow in selected groups of patients with diffuse liver disease and portal hypertension.
