Prenatal MRI evaluation of congenital diaphragmatic hernia.

The objective of this paper is to evaluate the efficacy of various magnetic resonance imaging (MRI) sequences and the general usefulness of prenatal MRI in determining the position of the fetal liver and visualizing lung tissue in fetuses who have congenital diaphragmatic hernia (CDH). This was a retrospective review of prenatal MRI of fetuses with a confirmed diagnosis by surgery or autopsy of CDH. MRI was performed in a 1.5-Tesla magnet using fast gradient echo, half-Fourier single-shot turbo spin-echo (HASTE) and echo planar images. The presence of a chest mass, position of the stomach and liver and visualization of the lungs by MRI was noted in all fetuses. This was compared to ultrasound studies performed the same day and correlated with postnatal or autopsy studies. The fetuses were 18-36 weeks gestational age (mean 24.5 weeks). MRI diagnosed left CDH (33), right CDH (4), and bilateral CDH (1) and agreed with the postnatal diagnosis in all patients. Ultrasound (US) diagnosed left CDH (33), right CDH (2), and congenital cystic adenomatoid malformation (3). MRI changed the diagnosis in four patients. The fetal liver was easily demonstrated with MRI in all fetuses and was herniated into the chest in 25 of the 38. US diagnosed liver up in 21. Correlation with postnatal studies found MRI correctly diagnosed liver position in 37 out of 38 cases. US correctly diagnosed liver position in 32 out of 38. Both lungs could be visualized in all fetuses with MRI. MRI accurately and easily diagnoses CDH and can differentiate it from other chest masses. MRI was superior to US in demonstrating the position of the fetal liver above or below the diaphragm. MRI reliably visualized fetal lung tissue. These findings are important for counseling parents, selecting fetal surgical candidates, and estimating prognosis.