AIM:To investigate the correlation of enhancement featuresof hepatocellular carcinoma (HCC) revealed by single-leveldynamic spiral CT scanning (DSCT) with tumor microvesseldensity (MVD),and to determine the validity of DSCT inassessing in vivo tumor angiogenic activity of HCC.METHODS:Twenty six HCC patients were diagnosedhistopathologically.DSCT was performed for all patientsaccording to standard scanning protocol.Time-density curveswere generated,relevant curve parameters were measured,and gross enhancement morphology was analyzed.Operationwas performed to remove HCC lesions 1 to 2 weeks followingCT scan.Histopathological slides were carefully prepared forthe standard F_8RA immunohistochemical staining and tumormicrovessel counting.Enhancement imaging features of HCClesions were correlatively studied with tumor MVD and itsintra-tumor distribution characteristics.RESULTS:On DSCT images of HCC lesions,three patternsof time-density curve and three types of gross enhancementmorphology were recognized.Histomorphologically,thedistribution of positively stained tumor endothelial cells withintumor was categorized into 3 types.Curve parameters suchas peak enhancement value and contrast enhancement ratiowere significantly correlated with tumor tissue MVD (r=0.508and r=0.423,P<0.01 and P<0.05 respectively).Both thepattern of time-density curve and the gross enhancementmorphology of HCC lesions were also correlated with tumorMVD,and reflected the distributive features of tumormicrovessels within HCC lesions.Correlation between thelikelihood of intrahepatic metastasis of HCC lesions withdensely enhanced pseudocapsules and rich pseudocapsulartumor MVD was found.CONCLUSION:Enhancement imaging features of HCClesions on DSCT scanning are correlated with tumor MVD,and reflect the intra-tumor distribution characteristics of tumor microvessels.DSCT is valuable in assessing theangiogenic activity and tumor neovascularity of HCC patientsin vivo. To investigate the correlation of enhancement features of hepatocellular carcinoma (HCC) revealed by single-leveldynamic spiral CT scanning (DSCT) with tumor microvessel density (MVD), and to determine the validity of DSCT inassessing in vivo tumor angiogenic activity of HCC. METHODS: Twenty-six HCC patients were diagnosedhistopathologically. DSCT was performed for all patientsaccording to standard scanning protocol.Time-density curveswere generated, relevant curve parameters were measured, and gross enhancement morphology was analyzed. Operation was performed to remove HCC lesions for 1 to 2 weeks followingCT scan. Histopathological slides were carefully prepared forthe standard F_8RA immunohistochemical staining and tumormicrovessel counting. Enhancement imaging features of HCClesions were correlatively studied with tumor MVD and itsintra-tumor distribution characteristics .RESULTS: On DSCT images of HCC lesions, three patterns of time-density curve and three types of gross enhancementmorphology wer e recognized. Histomorphologically, thedistribution of positively stained tumor endothelial cells with intumor was categorized into 3 types. Curve parameters suchas peak enhancement value and contrast enhancement ratiowere significantly correlated with tumor tissue MVD (r = 0.508 and r = 0.423, P <0.01 and P < 0.05 respectively) .Both thepattern of time-density curve and the gross enhancementmorphology of HCC lesions were also correlated with tumorMVD, and reflected the distributive features of tumormicrovessels within HCC lesions.Correlation between thelikelihood of intrahepatic metastasis of HCC lesionswithdensely enhanced pseudocapsules and rich pseudocapsulartumor MVD was found. CONCLUSION: Enhancement imaging features of HCClesions on DSCT scanning are correlated with tumor MVD, and reflect the intra-tumor distribution characteristics of tumor microvessels. DSCT is valuable in assessing theangiogenic activity and tumor neovascularity of HCC patients in vivo.