Abstract： Objective To compare the concordance,intersonographer and intrasonographer variance of measurement of fetal nuchal translucency (NT) via semi-automated system (SonoNTTM) and manual operation.Methods The profiles of 58 healthy fetuses during early pregnancy for ultrasonographic examination in our hospital between February 2011 and April 2011 were analyzed,and the images of abdominal ultrasonographic measurement of NT at standard section were saved.Assessment of NT was performed by an experienced sonographer using semi-automated system and manual operation respectively,thus allowing for measurement of between-test consistency.A total of 30 fetuses ultrasound images was further randomly selected via random-number table,followed by check twice using semi-automated system and manual operation by two sonographers with different experience for subsequent analysis of intersonographer and intrasonographer variance.Results The experienced sonographer yielded the mean NT of (1.40±0.39) mm and (1.44±0.42) mm among 58 fetuses by manual operation and SonoNTTM (P=0.045) respectively.This gave an interclass correlation coefficient (ICC) of 0.928(P=0.000),mean between-test variability of (0.042±0.160) mm and 95％ consistency range of (-0.278to 0.362) rm.Of the profiles in 30 fetuses being analyzed,ICC of the experienced sonographer was 0.997(P=0.000) for SonoNTTM and 0.965 (P=0.000) for manual operation,while these figures were 0.993 (P=0.000) and 0.889 (P=0.000) for the inexperienced sonographer.Between-sonographer measurement was associated with an ICC of 0.963 (P=0.000) for SonoNTTM and 0.970 (P=0.000) for manual operation.Conclusions Result of NT measured by SonoNTTM is higher than that of manual operation while both approaches are featured of preferable correlation.SonoNTTM reduces intersonographer and intrasonographer variance particularly among inexperienced sonographers.