Fetal lung volume measurements using 3D ultrasonography.

PURPOSE: The aim of the study was to establish fetal lung, thoracic and heart volume nomograms using three-dimensional (3D) ultrasonographic measurements.

MATERIALS AND METHODS: For this purpose a total of 300 fetuses were examined between 18 and 34 weeks of gestation using Voluson 530 ME and Voluson 730 PRO (General Electic, USA) ultrasound devices with 5 MHz three-dimensional annular volume transducers. To determine fetal lung volume, each lung was measured separately using a transversal sectional plane in the multiplanar mode. Measurements were performed by area tracing around the fetal lung in cross-sectional planes in different slices. The distance between two represented slices was calculated by computer. Calculated volume data was plotted against gestational age in order to obtain nomograms of fetal lung, heart and thorax volumes.

RESULTS: Our nomograms revealed increasing lung, heart and thoracic volume growth between 22 and 34 weeks of gestation. Furthermore, we could demonstrate that there is a statistically significant difference between the growth of the right and left lung volume (right > left). In a group of 12 fetuses with skeletal dysplasias or hydrothorax pulmonary hypoplasia was suspected by ultrasound. Comparing two-dimensional (2D) sonographic measurements of oblique lung diameter and 3D lung volumetry, it was found that these two methods were complementary for the recognition of pulmonary hypoplasia before the 24 weeks of gestation.

CONCLUSION: Using 3D ultrasound it is easy to perform fetal lung volumetry especially before 30 weeks of gestation. The encouraging results suggest that this method could be useful for the early detection of pulmonary hypoplasia even before 24 weeks of gestation.