PURPOSE: The purpose of this study was to compare true-fast imaging with steady state precession(t-FISP) with enhanced fast low-angle shot(e-FLASH) imaging of the abdomen in the assessment of the normal and abnormal portal venous(PV) system. MATERIALS AND METHODS: In order to evaluate the PV system, MR images using both t-FISP and e-FLASH sequences were obtained in 62 patients with hepatic mass. In 56 cases in which PV thrombosis was not demonstrated, images were evaluated for homogenity and artifacts within the lumen of the PV system and the margin of the main PV. In the other six cases of PV thrombosis, conspicuity and extent of the thrombus were also compared . RESULTS: For each vessel, the mean score for homogeneity and artifacts was significantly higher in t-FISP images than in e-FLASH images(P<.05), as were mean scores for the margin of the main PV (P < .05). In six patients with PV thrombosis, conspicuity of the thrombus as seen on t-FISP images was superior to that seen on e-FLASH images; similarly, the exact extent of the thrombus was more accurately defined on the former type of image. CONCLUSION: For evaluation of the PV system, t-FISP MRI provides better imaging quality and better conspicuity with regarded to the site and extent of PV thrombus, as compared with e-FLASH images.