Reliability of prenatal sonographic lung biometry in the diagnosis of pulmonary hypoplasia

Objective-The purpose of the present study was to assess the value of biome tric lung measurements for the diagnosis of severe fetal pulmonary hypoplas ia by investigating whether a significant correlation between two-dimension al lung biometry measurements and autopsy findings could be established. Methods-This was a prospective study carried out between 1995 and 1997. Nom ograms for normal fetuses of the arterior-posterior and transverse inner th oracic diameters, which describe the growth and shape of the lung, were use d as a basis for diagnosis of pulmonary hypoplasia in fetuses at high risk of developing the condition (the fetuses had bilateral renal agenesis or mu lticystic kidneys; chronic PROM < 25 gestational weeks or hydrothorax). Pre gnancy was terminated by abortion or intrauterine death in 29/43 high-risk fetuses and autopsies were performed. Only the 29 fetuses for which there w ere autopsy findings were included in the study. Results-The best plane for diagnosing pulmonary hypoplasia was the four-cha mber view. The diagnostic accuracy for this view as expressed by the sensit ivity was 57% for the anterior-posterior diameter and 44% for the transvers e diameter; as expressed by the specificity it was 42% for the anterior-pos terior diameter and 50% for the transverse diameter. The results for the fo ur-chamber view for the various high-risk conditions were as follows: for f etuses with chronic PROM we obtained sensitivities of 75% and 50% (anterior -posterior and transverse dimensions, respectively) and specificities of 80 % and 60% (anterior-posterior and transverse dimensions, respectively). The sensitivities of lung biometry in fetuses with hydrothorax were 1% and 80% for the two diameters, but there was a low specificity. In fetuses with bi lateral renal agenesis or multicystic kidneys we obtained sensitivities of 36% and 30% (anterior-posterior and transverse dimensions, respectively) an d a specificity of 50% (anterior-posterior dimension). Conclusions-The pesent results show that two-dimensional lung biometry is n ot a suitable method for antenatal detection of pulmonary hypoplasia. Howev er, in individual cases with high risk for pulmonary hypoplasia, lung biome try might prove to be an additional diagnostic parameter. Copyright (C) 200 1 John Wiley & Sons, Ltd.