Fetal lung volumetry by three-dimensional ultrasound.

The aim of this study was to establish a method for determination of fetal lung volume by three-dimensional ultrasound. The thoraces of a total of 113 fetuses (singleton pregnancies, 11-41 weeks of gestation without any signs of malformation or oligohydramnios) were examined by three-dimensional ultrasound. Volumetric evaluation of each lung was performed in each of three perpendicular planes (six measurements in total). There were significant differences in all three measurements between the left and right lungs. Especially in the second and third trimesters, measurement of the frontal and the sagittal planes was sometimes prevented by poor imaging conditions. The scan volume was always too small for fetuses above 34 weeks. With these problems considered, nomograms of fetal lung volume for the left and the right lung were calculated. Lung volumes in the present study showed good correlation with published autopsy findings. Three-dimensional ultrasonographic volumetry is a useful method for determining fetal lung volume and may have a role to play in the detection of pulmonary hypoplasia.