Predicting Pulmonary Hypoplasia Using Virtual Organ Computer Aided Analysis Technique

ObjectivePulmonary hypoplasia is due to a decrease in the number of lung cells, airways and alveoli, with a resulting decrease in organ size and weight. Since pulmonary hypoplasia may lead to severe respiratory distress immediately after birth and even to neonatal death, an accurate prenatal diagnosis becomes more and more important. The objective of this study was to determine the accuracy of VOCAL technique in estimating the fetal lung volume, and to evaluate the potential of ultrasonic fetal lung to body weight ratio in fetal pulmonary hypoplasia diagnosis.MethodsBetween November 2008 and February 2010, a prospective study was conducted in the Shengjing Hospital of China Medical University. Lung volumes were estimated by VOCAL technique and fetal weights were measured by two-dimensional ultrasound (Hadlock equation) in 35 fetuses(16w-36w). The fetuses were diagnosed with congenital abnormalities prenatally and the gravidas agreed autopsy. The lung volumes aquired by VOCAL technique was compared with the pathological volume aquired postnatally, and finally the value of UFLB in fetal pumonary hypoplasia diagnosis was evaluated.ResultsThe bias of the fetal lung volume estimated by the two methods was-0.81±1.77cm3.The intraclass correlation coefficient of fetal lung volume estimated by VOCAL technique was 0.953. The sensitivity and specificity of the UFLB for diagnosing PH were 83.33% and 95.65%, respectively, the positive and negative predictive values were 90.91% and 91.67%, and the accuracy was 91.43%.The UFLB was significantly lower in fetuses with pulmonary hypoplasia than it was in those without pulmonary hypoplasia (P< 0.05)Conclusion1. The fetal lung volume can be estimated precisely by three-dimensional ultrasound using VOCAL technique. The fetal lung volume reflects the development of fetal lung, which provides a new way of estimating fetal pumonary development.2. The results aquired by the same operator three times presents high repeatability, which further proven the feasibility of VOCAL in estimating fetal lung volume.3. UFLB can be used to estimate pulmonary hypoplasia precisely, and there's a great difference between UFLB in fetuses with pulmonary hypoplasia and that in those without pulmonary hypoplasia. Finally it provides an effective method for prenatal diagnosis of pulmonary hypoplasia.