AIM: To determine the validity of the non-invasive method of CT perfusion (CTP) in rat model of hepatic diffuse disease. METHODS: Twenty-eight Wistar rats were divided into two groups. Liver diffuse lesions were induced by dietthylnitrosamine in 14 rats of test group. Rats in control groupwere bred with pure water. From the 1st to 12th wk after the test group was intervened, both groups were studied every week with CTP. CTP parameters of liver parenchymain different periods and pathologic changes in two groups were compared and analyzed.RESULTS: The process of hepatic diffuse lesions in test groups was dassified into three stages or periods according to the pathologic alterations, namely hepattitis, hepatic fibrosis, and cirrhosis. During this period, hepatic artery flow (HAF)of control group declined slightly, mean transit time (MTT),blood flow (BF) and volume (BV) increased, but there wereno significant differences between different periods. Tntest group, HAF tended to increase gradually, MTT prolonged obviously, BV and BF decreased at the same time. The results of statistical analysis revealed that the difference in the HAF ratio of test group to control group was significant.The ratio of BV and BF in test group to control group in stageof hepatitis and hepatic cirrhosis, hepatic fibrosis and early stage of hepatic cirrhosis was significantly different, but there was no significant difference between hepatitis and hepatic fibrosis. The main pathological changes in stage of hepatitis were swelling of hepatic cells, while sinusoid capillarization and deposition of collagen aggravated gradually in the extravascular Disses spaces in stage of fibrosis and early stage of cirrhosis.CONCLUSION: The technique could reflect some early changes of hepatic blood perfusion in rat with liver diffuse disease and is valuable for their early diagnosis.