Objective To conclude the characterization of renal cellular carcinoma(RCC)with contrast enhanced ultrasound.Methods Seventy patients(seventy-two nodules)with RCC,which were confirmed by operation and biopsy underwent conventional ultrasound and contrast-enhanced ultrasound(CEUS).Microbubble agents SonoVue and contrast pulse sequence(CPS)were used.The conventional uItrasonographic characterization and the enhancement patterns of lesions were analyzed.Results On baseline sonography,the numbers of lesions that showed hypoechogenicity,isoechogenicity,and hyperechogenicity were 44.4%(32/72),25.0%(18/72)and 30.6%(22/72),respectively.Only 28 lesions(38.9%)showed flow signals on color Doppler sonography,the mean maximum velocity of which WSS(43.7±16.8)cm/s(range,24.8-95 cm/s),and the mean resistance index was 0.635±0.11(range.0.52-0.83).Sixty-three(87.5%)lesions were hyper-vascular in cortical phase.Among them forty-eight(76.2%)lesions were hypo-enhanced,and fifteen(23.8%)lesions were still hyper-vascular in late phase.The remaining nine hypervascular nodules in cortical phase were still hyper-enhancing in late phase.Fifty-four(75.0%)lesions were inhomogeneous enhancement.and pseudocapsule was observed in sixty-three(87.5%)RCC lesions.Conclusions The enhancement patterns of RCC are characteristic,and CEUS may be helpful in differential diagnosis of focal renal lesions.