| Background Placental implantation spectrum according to the depth of invasion of the muscle layer is divided into:placenta accerta,placenta increta and placenta percreta,the former two collectively known as non penetrating placenta implantation.At present,it is not difficult to do the prenatal diagnosis of placenta percreta by ultrasound and MRI,but it is still difficult to distinguish the placenta accerta from the placenta increta.Objective To investigate the feasibility of quantitative analysis of non penetrating placenta implantation by three-dimensional power Doppler ultrasound and its postprocessing,and the clinical value in differentiating placenta accreta from placenta increta.Methods From January 2018 to January 2019,34 pregnant women,aged 24-47 years old and 31-38 weeks of gestation,who were admitted for the two-dimensional color Doppler ultrasound examination and clinical preliminary diagnosis non penetrating placenta implantation,all patients had placenta previahad and one or more risk factors as the history of induced abortion,medical abortion,cesarean section,hysteromyoma surgery,hysteroscopy and other high-risk factors,the placenta percreta was excluded,and so as poor image quality is caused by multiple pregnancy,congenital uterine malformation,abdominal fat layer is too thick or can not cooperate with the examination.The clinical data of the pregnant women were complete.The two-dimensional color Doppler ultrasound images and three-dimensional power Doppler ultrasound power Doppler signal area of the placenta-uterus interface were retrospectively analyzed.According to the surgical results as the gold standard,they were divided into non placental implantation group and non penetrating placenta implantation group according to the surgical results,and the latter was further divided into placenta accreta group and placenta increta group.Two dimensional color ultrasound alone or in combination with three-dimensional power Doppler ultrasound and the power Doppler signal area of placenta-uterus interface were used to evaluate the consistency of prenatal diagnosis results with the gold standard,and calculate the sensitivity,specificity and accuracy.The degree of variation of the area value of power Doppler signal in the placenta-uterus interface was analyzed,and the threshold value of diagnosis was quantified.Results 1.According to the results of operation,10 cases were diagnosed as non placental implantation group,24 cases were non penetrating placenta implantation group(11 cases were placenta accreta group,13 cases were placenta increta group).2.Two dimensional color Doppler ultrasound correctly diagnosed 26 cases of non penetrating placenta implantation,9 cases of differential typing,combined with three-dimensional power Doppler ultrasound and its postprocessing correctly diagnosed 30 cases,13 cases of differential typing;The sensitivity of the two methods was 79.17%and 87.50%respectively;The specificity was 70.00%and 90.00%respectively;The accuracy was 76.47%,88.24%respectively;The accuracy of identification of placenta accreta was 0.00%、18.18%;The accuracy of identification of placenta increta was 69.23%and 84.62%.3.The median and interquartile distance of power Doppler signal area of placenta-uterus interface in non penetrating placenta implantation group(84.30 cm2,50.37 cm2(P25=52.73,P75=103.10))were significantly larger than those in non placental implantation group(12.30 cm2,5.20 cm2(P25=11.10,P75=16.30)),the difference between the two groups was statistically significant(P=0.000).The median and interquartile distance of power Doppler signal area of placenta-uterus interface in placenta increta group(82.55 cm2,48.78 cm2(P25=58.58,P75=107.35))was smaller than that in placenta accreta group(90.80 cm2,77.95 cm2(P25=35.33,P75=113.28)),and there was no significant difference between the two groups(P=0.671).4.According to ROC curve,when the area of power Doppler signal at the placenta-uterus interface is greater than or equal to 33.7 cm2,the sensitivity and specificity of diagnosing non penetrating placenta implantation are 87.50%and 100.00%,respectively.Conclusion 1.The area of power Doppler signal of placenta-uterus interface obtained by three-dimensional power Doppler ultrasound and its postprocessing combined with two-dimensional color Doppler ultrasound can further improve the accuracy of prenatal diagnosis and classification of non penetrating placenta implantation,which can be used as a new quantitative analysis method.2.Two dimensional color Doppler ultrasound is the preferred screening method for placental implantation.Three dimensional power Doppler ultrasound can be used as a necessary imaging supplement when the diagnosis of placental implantation is difficult or the use of MRI is limited.3.There was no significant difference of three-dimensional power Doppler signal area of placenta-uterus interface in the median and quartile distance between the placenta accreta group and placenta increta group,so it is not possible to distinguish placenta accreta and placenta increta completely by the area of power Doppler signal at placenta-uterus interface of three-dimensional power Doppler ultrasound.It is necessary to expand the sample size for further study. |
PDF Full Text Request