AIM: To investigate the hemodynamic changes in a precancerous lesion model of hepatocellular carcinoma (HCC).METHODS: Hemodynamic changes in 18 Wistar rats were studied with non-invasive magnetic resonance (MR)perfusion. The changes induced by diethylnitrosamine (DEN) developed into liver nodular lesions due to hepatic cirrhosis during the progression of carcinogenesis.The MR perfusion data [positive enhancement integral (PEI)] were compared between the nodular lesions corresponding well with MR images and pathology and their surrounding hepatic parenchyma.RESULTS: A total of 46 nodules were located by MR imaging and autopsy, including 22 dysplastic nodules (DN), 9 regenerative nodules (RN), 10 early HCCs and 5 overt HCCs. Among the 22 DNs, 6 were low-grade DN (LGDN) and 16 were high-grade DN (HGDN). The average PEI of RN, DN, early and overt HCC was 205.67± 31.17, 161.94 ± 20.74, 226.09 ± 34.83, 491.86 ±44.61 respectively, and their liver parenchyma nearby was 204.84 ± 70.19. Comparison of the blood perfusion index between each RN and its surrounding hepatic parenchyma showed no statistically significant difference (P = 0.06). There were significant differences in DN (P = 0.02). During the late hepatic arterial phase, the perfusion curve in DN declined. DN had an iso-signal intensity at the early hepatic arterial phase and a low signal intensity at the portal venous phase. Of the 10early HCCs, 4 demonstrated less blood perfusion and 6 displayed minimally increased blood flow compared to the surrounding parenchyma. Five HCCs showed significantly increased blood supply compared to the surrounding parenchyma (P = 0.02).CONCLUSION: Non-invasive MR perfusion can detect changes in blood supply of precancerous lesions.