| PartⅠ: Evaluation of placental elasticity in normal pregnancy by shear wave elastography and its influencing factors Objective To explore the feasibility of shear wave elastography in evaluating placental elasticity,analyze the influencing factors of Young’s modulus of placenta in normal pregnancy and establish the normal reference range.Methods Shear wave elastography was used by the same doctor to measure the placental elasticity of 224 normal pregnant women between 20 and 40 gestational weeks.The regions of interest were detected in the central-fetal surface,central-maternal surface,peripheral-fetal surface and peripheral-maternal surface of each placenta,and the mean,min and max of Young’s modulus were recorded.The correlation between all measurements and sampling regions,gestational weeks,placental maturity grading,sampling depth was analyzed.20 normal pregnant women collected randomly was examined by the same one and two different physicians,to analyze the repeatability and consistency reliability.Results(1)There was no significant difference in Young’s modulus among different sampling regions(P>0.05).(2)The mean,min and max of Young’s modulus were not found to be associated with gestational weeks(r=0.119,P=0.076;r=0.089,P=0.184;r=0.079,P=0.238).The mean,min and max of Young’s modulus were not found to be associated with placental maturity grading(r=0.107,P=0.109;r=0.037,P=0.584;r=0.103,P=0.124).The mean,min and max of Young’s modulus were not found to be associated with sampling depth(r=0.013,P=0.851;r=0.046,P=0.497;r=-0.066,P=0.327).(3)The repeatability and consistency reliability of the measurements obtained by the same or two different physicians were good.Conclusion SWE can be used to measure young’s modulus of placenta and quantitatively analyze the elasticity of placenta with good repeatability and consistency reliability.The mean,min and max of Young’s modulus of placenta had no relationship with sampling regions,different gestational weeks,placental maturity and sampling depth.Establish the normal reference range of Young’s modulus of placenta.PartⅡ: Shear wave elastography in evaluation of placenta in preeclampsiaObjective Shear wave elastography was used to measure placental elasticity,compare Young’s modulus of placenta between normal and preeclampsia pregnant women,and analyze the evaluation value of SWE for placenta in preeclampsia.Methods Shear wave elastography was used to measure the placental elasticity of 50 preeclampsia patients and 50 normal pregnant women.The regions of interest were detected in the central-fetal surface,central-maternal surface,peripheral-fetal surface and peripheral-maternal surface of each placenta,and the mean,min and max of Young’s modulus were recorded.Mann-whitney U test was used to compare whether there was difference in placental elasticity between PE group and control group.The correlation between all measurements and sampling areas,hemodynamic parameters of bilateral uterine arteries,Apgar scores at 1st and 5th minute,soluble fms-like tyrosine kinase-1 in serum was analyzed.Receiver operating characteristic curves were plotted to obtain the best cut-off value for elasticity values,and its sensitivity,specificity were calculated.Results(1)Placental Young’s values were significantly higher in preeclamptic patients(P<0.05).(2)There was no significant difference in Young’s modulus of all measurements among the sampling regions(P>0.05).(3)The mean,min and max of Young’s modulus showed moderately negative correlation with the birth weight(r=-0.544,P<0.05;r=-0.506,P<0.05;r=-0.499,P<0.05).The mean,min and max of Young’s modulus showed moderately positive correlation with the right uterine artery pulsatility indices(r=0.536,P<0.05;r=0.482,P<0.05;r=0.517,P<0.05).The mean,min and max of Young’s modulus showed moderately positive correlation with the left uterine artery pulsatility indices(r=0.540,P<0.05;r=0.488,P<0.05;r=0.521,P<0.05).The mean,min and max of Young’s modulus showed moderately positive correlation with the right uterine artery resistivity indices(r=0.436,P<0.05;r=0.400,P<0.05;r=0.422,P<0.05).The mean,min and max of Young’s modulus showed moderately positive correlation with the left uterine artery resistivity indices(r=0.431,P<0.05;r=0.395,P<0.05;r=0.413,P<0.05).The mean,min and max of Young’s modulus showed moderately negative correlation with the Apgar scores at 1st minute(r=-0.406,P<0.05;r=-0.353,P<0.05;r=-0.403,P<0.05).The mean,min and max of Young’s modulus showed lightly negative correlation with the Apgar scores at 5th minute(r=-0.292,P<0.05;r=-0.271,P<0.05;r=-0.298,P<0.05).The mean,min and max of Young’s modulus showed moderately positive correlation with soluble fms-like tyrosine kinase-1 in serum(r=0.751,P<0.05;r=0.704,P<0.05;r=0.748,P<0.05).(4)The area under curve for predicting preeclampsia by the mean of Young’s modulus was 0.935 and the cut-off value maximizing the accuracy of diagnosis was 5.1 k Pa.The sensitivity,specificity,positive predictive value,and negative predictive value were 84%,100%,100% and 86% respectively,and the coincidence rate was 92%.The area under curve for predicting preeclampsia by the min of Young’s modulus was 0.891 and the cut-off value maximizing the accuracy of diagnosis was3.85 k Pa.The sensitivity,specificity,positive predictive value,and negative predictive value were 80%,98%,98% and 83% respectively,and the coincidence rate was 89%.The area under curve for predicting preeclampsia by the max of Young’s modulus was 0.926 and the cut-off value maximizing the accuracy of diagnosis was 8.15 k Pa.The sensitivity,specificity,positive predictive value,and negative predictive value were 80%,100%,100% and 83% respectively,and the coincidence rate was 90%.Conclusion Placental Young’s values were significantly higher in patients with preeclampsia compared to the control group.Shear wave elastography has a certain correlation with hemodynamics and placental function,it can be used as a noninvasive method to evaluate placental status,opening a new path for the evaluation of preeclampsia. |
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