Assessment of fetal lung development in using two-dimensional ultrasonography

Abstract

Objective To explore the application value of two-dimensional ultrasonic measurement of fetal left and right lung area, left and right pulmonary longitudinal diameter, left and right lung volume and total lung volume in evaluation of fetal lung development. Methods In 489 cases of normal singleton pregnancy, two-dimensional ultrasound scanning were conducted at 12-40 weeks. The left and right lung area was traced in the four chamber view using Trace method. The distances of left diaphragmatic dome to left lung apex and the right diaphragmatic dome to right lung apex were measured respectively on the left and right fetal lung parasagittal planes. Then calculation of left and right lung volume and total lung volume was carried out. Results Spearman correlation coefficient of gestational age and left and right lung area, left and right pulmonary longitudinal diameter, left lung volume and total lung volume were 0.929, 0.923, 0.923, 0.917, 0.946, 0.943, 0.951, and a positive correlation, with statistical significance (P<0.05). At 12-40 weeks, fetal left and right lung area, left and right pulmonary longitudinal diameter, left and right lung volume and total lung volume increased with gestational age and fetal growth. Pulmonary area increased faster before 26 weeks than that after 26 weeks. Pulmonary longitudinal diameter and lung volume grew at a constant rate throughout pregnancy, but the growth rate of pulmonary longitudinal diameter was slightly faster than that of lung volume. The fifth, twenty-fifth, fiftieth, seventy-fifth, ninety-fifth percentile of fetal left and right lung volume and total lung volume at 12-40 weeks were obtained. Conclusions Fetal left and right lung area, left and right pulmonary longitudinal diameter, left and right lung volume and total lung volume were positively correlated with gestational age between 12 and 40 week. The normal values of lung volume and total lung volume provide a reference index for prenatal diagnosis of fetal pulmonary hypoplasia. The fetal four chamber view and fetal left parasagittal section was easy to obtain, and may serve as a new conventional method in evaluating fetal lung developments. Key words: Ultrasonography; Fetus; Lung; Fetal development