Role of magnetic resonance imaging in fetal surgery.

Prenatal magnetic resonance imaging (MRI) has several advantages over obstetric ultrasound, including a larger field of view, superior soft-tissue contrast, more precise volumetric measurements, and greater accuracy in the demonstration of intracranial abnormalities. Prenatal MRI has been shown to positively and incrementally influence management in a substantial proportion of patients being considered for fetal intervention. Despite these findings, precise indications for prenatal MRI in the setting of fetal surgery are not yet established, because both prenatal MRI and fetal surgery are relatively new techniques that remain in evolution. Conditions in which prenatal MRI appears to contribute to fetal surgical planning and postoperative evaluation are described in this review. These conditions include congenital diaphragmatic hernia, cystic adenomatoid malformation, sacrococcygeal teratoma, complicated twin pregnancies, upper airway obstruction, and myelomeningocele.