AIM: To prospectively assess the changes in parameters of computed tomography (CT) perfusion pre- and post-transarterial chemoembolization (TACE) of hepatocellular carcinoma (HCC) in different treatment response groups,and to correlate the changes with various responses of HCC to TACE.METHODS: Thirty-nine HCC patients underwent CT perfusion examinations pre-(1 d before TACE) and post-treatment (4 wk after TACE).The response evaluation criteria for solid tumors (RECIST) were referred to when treatment responses were distributed.Wilcoxon-signed ranks test was used to compare the differences in CT perfusion parameters pre- and post-TACE for different response groups.RESULTS: Only one case had treatment response to CR and the CT perfusion maps of post-treatment lesion displayed complete absence of signals.In the PR treatment response group,hepatic artery perfusion (HAP),hepatic arterial fracture (HAF) and hepatic blood volume (HBV) of viable tumors POst-TACE were reduced compared with pre-TACE (P = 0.001,0.030and 0.001,respectively).In the SD group,all CT perfusion parameters were not significantly different pre- and post-TACE.In the PD group,HAP,HAF,portal vein perfusion (PVP) and hepatic blood flow (HBF) of viable tumors post-TACE were significantly increased compared with pre-TACE (P = 0.005,0.012,0.035 and 0.005,respectively).CONCLUSION: Changes in CT perfusion parameters of viable tumors are correlated with different responses of HCC to TACE.Therefore,CT perfusion imaging is a feasible technique for monitoring response of HCC to TACE.