Fetal lung volume measurement by magnetic resonance imaging in congenital diaphragmatic hernia

Objective To study the potential for prenatal magnetic resonance imaging to predict pulmonary hypoplasia in congenital diaphragmatic hernia. Design Prospective observational study. Setting Tertiary care centre. Participants Thirteen cases of congenital diaphragmatic hernia (11 left, 2 right) without associated anomalies and 74 controls. Methods Measurements by magnetic resonance imaging of fetal lung volume wer e achieved. In the control fetuses, a regression analysis was performed to associate fetal lung volume with gestational age. This yielded a formula al lowing calculation of the expected fetal lung volume as a function of gesta tional age. In the cases with congenital diaphragmatic hernia, the observed /expected fetal lung volume ratio was compared with perinatal outcome. Main outcome measures Neonatal mortality and pulmonary hypoplasia, which wa s defined as lung/body weight ratios less than 0.012. C, Results The expected fetal lung volume was derived from the following formu la: Fetal lung volume (mL) exp (1.24722 + 0.08939 X gestational age in week s). The observed/expected fetal lung volume ratio was significantly lower i n congenital diaphragmatic hernia (median: 0.31, range: 0.06-0.63), than in controls (median: 0.99, range: 0.42-1.94). This ratio was significantly le ss in the infants with congenital diaphragmatic hernia who died (median: 0. 26, range: 0.06-0.63) compared with those who survived (median: 0.46, range : 0.35-0.56). The observed: expected fetal lung volume ratio was significan tly correlated with the postmortem lung: body weight ratio. Conclusion In isolated con-enital diaphragmatic hernia, fetal lung volume m easurement by magnetic resonance C imaging is a potential predictor of pulm onary hypoplasia and postnatal outcome. Further studies are required C, to establish the clinical value of macynetic resonance imaging for the prenata l assessment of fetal lungs.