Fetal lung volume assessment based on 3-dimensional prenatal ultrasound / 中华超声影像学杂志

ABSTRACT

ObjectiveTo measure fetal lung volumes in different gestational age (GA) by using 3D ultrasound,and further to obtain the regression formula between fetal lung volume and GA.MethodsTotal 228 fetal lung data had been collected.By using the 3D reconstruction function in Philips Qlab,fetal lung volumes were obtained by subtracting the non lung volumes from the whole thoracic volumes.For each slice of 3D data,thoracic area and non-lung area were manually outlined.The contour stacking technique in Qlab was then used to transform 2D slices into 3D volumes.ResultsThe measurement results of total 228 cases indicate that the fetal lung volumes increase with the GA.The average lung volume at GA of 20 weeks was 8.85 cm3,and 70.5 cm3 at 36 weeks.The fetal lung volume increases about 3- 4 cm3 in each week,and the increasing trend turns to a little lower after 24 weeks.During 33 to 34 week there was a great increasing in fetal volumes.Second-order regression,exponential regression and logarithmic regression were respectively used to characterize the relationship between fetal lung volume and GA.The second-order regression formula wasVolume =39.52 - 4.48 × GA + 0.149 × GA2.The exponential regression formula wasLn (Volume) =- 8.233 + 1.747 × Ln(GA2 ).The logarithmic regression formula wasLn(Volume) =- 2.413 + 0.29× GA- 0.003 × GA2.The correlation coefficients of three formulas are equal,with r =0.99,P ＜ 0.001.Conclusions 3D ultrasound fetal lung volume measurement is useful for fetal lung maturity assessment and thus can provide important referential information for prenatal diagnosis.