Fetal cervical teratoma: What is the role of fetal MRI in predicting pulmonary hypoplasia?

OBJECTIVE To determine whether total fetal lung volumes estimated by MRI could predict lethal pulmonary hypoplasia in a cohort of fetuses with cervical teratomas. METHODS We performed a retrospective cohort study of fetal cervical teratomas from January 1, 2005, through April 1, 2012. The primary outcome was the ability of total lung volumes measured by MRI to predict neonatal mortality specifically due to pulmonary hypoplasia. Measured lung volumes were compared to previously reported normal values. The percent of observed-to-expected lung volume and the percent predicted lung volume were calculated. The positive and negative predictive values were calculated for each variable. RESULTS Fetal MRI-derived total lung volumes 1 standard deviation below the median for gestational age had a positive predictive value of 100% in predicting lethal pulmonary hypoplasia. Conversely, total lung volumes above this level were uniformly associated with pulmonary survival (100% negative predictive value). Additionally, percent predicted lung volume ≤75.7 and observed-to-expected lung volume ≤68.3 were associated with lethal pulmonary hypoplasia. CONCLUSION In this small cohort, MRI-estimated lung volumes were helpful in predicting the presence of pulmonary hypoplasia complicating fetal cervical teratoma.