Clinical Study On The Evaluation Of Fetal Lateral Ventricular Volume By Three-Dimensional Ultrasonography

ObjectiveTo explore the method of evaluating fetal lateral ventricular volume by three-dimensional ultrasound,and try to establish the equation of the relationship between fetal lateral ventricular volume and gestational age.At the same time,the methods of evaluating the size of fetal lateral ventricle by three-dimensional ultrasound and conventional two-dimensional ultrasound were compared,and the correlation between the two methods and the significance of three-dimensional ultrasound were analyzed.MethodsAmong a total of 443 pregnant women with gestational age ranging from 18 to 32weeeks who underwent routine obstetrical ultrasound examination in Guangdong Women and Children Hospital from April 2019 to January 2020,there were 430 cases without fetal lateral ventriculomegaly as normal group,and 13 cases with varying degrees of fetal lateral ventriculomegaly as observation group.Two-dimensional and three-dimensional ultrasound were used to measure the width of the body of fetal lateral ventricle,the distance between anterior horn,fetal lateral ventricle volume,cranial volume and other related parameters.A method for measuring volume by three-dimensional ultrasound were defined:selecting the rotation angle when measuring;determining the initial section of the measurement.To compare the correlation between the width of the body of fetal lateral ventricle measured by two-dimensional ultrasound and the fetal lateral ventricle volume measured by three-dimensional ultrasound.The correlation between fetal cranial volume,the sum of bilateral ventricle volume,the ratio of lateral ventricle volume to cranial volume and gestational age was analyzed separately,and regression models were established.To compare the difference of volume data obtained by three-dimensional ultrasound between fetuses with lateral ventriculomegaly and normal fetuses,and to explore the significance of three-dimensional ultrasound in evaluating the size of fetal lateral ventricles.Results1.The correlation coefficient of fetal cranial volume was 0.997 when the rotation angle was 15°and 30°respectively,and there is no significant difference in the measurement results（P>0.05）.The correlation coefficient of fetal lateral ventricular volume was 0.963 when the rotation angle was 15°and 30°respectively,but the difference of measurement results is statistically significant（P<0.05）.2.There was a positive correlation between the width of fetal lateral ventricle measured by two-dimensional ultrasound and the volume of fetal lateral ventricle measured by three-dimensional ultrasound（P<0.01）,but the correlation was weak,and the correlation coefficient was only 0.269.3.The fetal cranial volume and lateral ventricular volume increase with the increase of gestational age.The relationship between fetal cranial volume and gestational age fit regressing equation was BV（cm³）=-57.228-2.325×GA+0.403×GA²（R²=0.947,P<0.01）.The relationship between the sum of bilateral ventricular volume and gestational age fit regressing equation was LV（cm3）=-0.774+0.169×GA（R²=0.580,P<0.01）.The ratio of left lateral ventricle volume,right lateral ventricle volume or the sum of bilateral lateral ventricle volume to cranial volume decreased with the increase of gestational age,and the relationship between the ratio and gestational week conformed to the S curve equation.The regressing equations were the ratio of left lateral ventricle volume to cranial volume=e^{（-6.644+57.357/GA）}（R²=0.802,P<0.01）,the ratio of right lateral ventricle volume to cranial volume=e^{（-6.727+58.995/GA）}（R²=0.800,P<0.01）,the sum of bilateral lateral ventricle volume to cranial volume=e^{（-6.005+58.655/GA）}（R²=0.839,P<0.01）.4.The volume of lateral ventricle of fetus with lateral ventriculomegaly is larger than normal fetus.The carinal volume of fetuses with lateral ventriculomegaly without other intracranial structural abnormalities was not larger than normal fetuses.The sum of bilateral ventricular volume and the ratio of lateral ventricular volume to carinal volume are related to the degree of fetal lateral ventricular dilatation.For some fetuses with mild and moderate lateral ventricular dilatation,the sum of bilateral ventricular volume and the ratio of the affected side lateral ventricular volume or the sum of bilateral ventricular volume to cranial volume were not larger than normal fetuses.Comparatively,for fetuses with severe dilatation of lateral ventricle,the sum of bilateral ventricular volume and the ratio of the affected side lateral ventricular volume or the sum of bilateral ventricular volume to cranial volume were significantly higher than those in normal fetuses.Conclusions1.The measurement of fetal lateral ventricle volume by three-dimensional ultrasound is feasible to evaluate the size of fetal lateral ventricle.2.The sum of bilateral ventricular volume and cranial volume of fetus were positively correlated with gestational age,which increased with the increase of gestational age.The relationship between the sum of bilateral ventricular volume and gestational age,cranial volume and gestational age conform respectively to the linear equation and quadratic equation.The ratio of the left lateral ventricle volume to cranial volume,the ratio of the right lateral ventricle volume to cranial volume or the ratio of the sum of bilateral lateral ventricle volume to cranial volume were negatively correlated with gestational age,which decreased with the increase of gestational age.The relationship between these ratio and gestational age was in accordance with the S-curve equation.3.The data related to the measurement of fetal lateral ventricular volume by three-dimensional ultrasound can provide more effective imaging information about the size of fetal lateral ventricle for the fetuses with isolated mild or moderate lateral ventricular dilatation.4.The distance between the anterior horn of the lateral ventricle of the fetus with isolated lateral ventriculomegaly will not be widened.