AIM:To assess the vascularity of hepatocellular carcinoma (HCC)before and after transcatheter arterial chemoembolization(TACE) with the quantitative parameters obtained by firstpass perfusion weighted MR imaging (FP-MRI).METHODS:Seventeen consecutive patients with one tothree lesions in liver underwent FP-MRI before treatment.FP-MRI was also performed one,three,six,nine months,and one year after TACE.The baseline signal intensity (SO)of pre-TACE and one month after TACE was analyzed,thevascularity of HCC assessed by steepest slope of the signalintensity versus time curves (SS) was blindly correlatedwith their DSA feature and clinical outcome.RESULT:No significant difference was found on baselinesignal intensity (S0) between pre-TACE and one monthafter TACE (F=0.309,P=0.583),The SS (mean,32% persecond) of lesion one month after TACE was lower than thatof pre-TACE (mean,69% per second),but with no statisticalsignificance (F=3.067,P=0.092).When local recurrenceoccurred,the time intensity curves became steeper.Thevascularity of HCC before and after TACE graded by SS closelycorrelated with that by DSA (K=0.453,P<0.05).CONCLUSION:FP-MRI is a useful criterion for selectingeffective interventional treatment for patients with HCC intheir initial treatment and during follow up.