Objective To investigate ultrasound features of port-wine stains (PWS),and to evaluate the diagnostic value of ultrasound imaging.Methods A total of 128 patients with pathologically or clinically confirmed PWS (162 lesions),who were also subjected to ultrasound examination,were collected from Shanghai Ninth People's Hospital affiliated to Shanghai Jiao Tong University School of Medicine between January 2015 and January 2016.According to ultrasound findings,these PWS lesions were divided into 3 types:flat type,hypertrophic type and nodular type,and the ultrasound features were retrospectively analyzed.Results For 95 patients with flat PWS (118 lesions),the skin thickness was significantly higher in the lesion areas than in the normal areas,but most of the thickness difference was less than 0.2 mm.Of the 118 lesions,79 (67％) showed hypoechoic areas,75 (64％) showed no blood flow signal,and the vein spectrum was detected in 15,with a peak of (3.33 ± 1.80) cm/s.For 17 patients with hypertrophic PWS (24 lesions),the lesion areas showed significantly increased skin thickness compared with the normal areas (1.80 ± 0.70 mm vs.1.14 ± 0.43 mm,t =6.834,P ＜ 0.001).All (100％) of the 24 lesions showed hypoechoic areas,low blood flow signals were observed in 15 (62％),and the vein spectrum was detected in 18 lesions,with a peak velocity of (6.61 ± 3.87) cm/s.For 16 patients with nodular PWS (20 lesions),the skin thickness in the lesion areas was (6.45 ± 4.68) mm.Of the 20 lesions,18 (90％) showed hypoechoic areas,and abundant blood flow signals were observed in 15 (75％).Additionally,the vein spectrum was detected in 15 lesions,with a peak velocity of (10.00 ± 5.39) cm/s,and the artery spectrum was detected in 19 lesions,with a systolic peak velocity of (24.58 ± 13.82) cm/s and a resistance index of 0.59 ± 0.13.The skin lesions was significantly thicker in the hypertrophic PWS group and nodular PWS group than in the flat PWS group (both P ＜ 0.05),and significantly thicker in the nodular PWS group than in the hypertrophic PWS group (P ＜ 0.05).The peak velocity of vein spectrum significantly differed among the 3 groups (F =10.630,P ＜ 0.001),and was significantly higher in the hypertrophic PWS group and nodular PWS group than in the flat PWS group (both P ＜ 0.05).However,no significant difference was observed between the hypertrophic PWS group and nodular PWS group (P ＞ 0.05).Conclusion Ultrasonography is,to a certain extent,valuable in the diagnosis of PWS.