The purpose of this study was to prospectively investigate the extent to which reduced portal blood flow in patients with hepatic cirrhosis and portal hypertension affects hepatic parenchymal enhancement during gadolinium-chelate-enhanced dynamic MR imaging. Breath-hold three-dimensional (3D) spoiled gradient-recalled echo (GRE) MR imaging technique obtained after intravenous administration of a gadolinium chelate was used to measure hepatic parenchymal enhancement and time to peak enhancement in 20 patients with hepatic cirrhosis and clinical evidence of portal hypertension (group 1) and in 20 control subjects without portal hypertension (group 2) who were matched for age, sex, and body weight. Mean peak hepatic enhancement values +/- SD and times to peak enhancement +/- SD were determined for both groups of patients. Mean peak enhancement value (+/-SD) was 78.7% +/- 36.2 in group 1 and 91.6% +/- 46.2 in group 2 (not significant). However, in the nine patients in group 1 with splenomegaly, mean peak enhancement value was 61.3% +/- 14.4, whereas it was 93.0% +/- 42.7 in the 11 patients without splenomegaly (P < .05). Mean time to peak enhancement was 84 seconds +/- 23 in group 1 and 54.0 sec +/- 25.0 in group 2 (P < .01). Our results show that mean peak enhancement value of hepatic parenchyma after intravenous administration of a gadolinium chelate is significantly altered for patients with portal hypertension and splenomegaly. In addition, the time to peak enhancement is delayed significantly when portal hypertension is present. Thus, it is possible that the optimal time for imaging the liver during the portal phase must be tailored to the status of the portal system of the patient.