Correlation of fetal MRI findings and need for postnatal VP shunt in children born with Myelomeningocele

Introduction: Myelomeningocele occur in about 3.4 per 10,000 births in the United States. Fetal MRI is being increasingly used after diagnosis to give detailed pictures of the anatomy. However, the long term prognostic value of fetal MRI is not well understood. In this study, we examined the degree of prenatal ventricular dilatation measured by MRI in fetuses with MMC and correlate to the need for postnatal ventriculoperitoneal (VP) shunt by 12 months of age. Methods: This was an IRB approved, retrospective study. We examined MRI imaging (n=24) of fetuses (mean 24 weeks gestation) diagnosed with myelomeningocele. Only fetuses that were carried to term were included in the study. Ventriculomegaly was evaluated on images by measuring lateral ventricle size at the frontal horns. Additional measurements and features included evaluation of 3rd and 4th ventricular dilatation, hindbrain herniation, and cisterna magna. Patients were evaluated for whether they had a VP shunt placed by one year of age. Results: Mean prenatal ventricle size was greater for patients who received a VP shunt postnatally compared to those who did not receive a VP shunt (p15mm, 100% (n=4) went on to receive a VP shunt postnatally. For fetuses with ventricle sizes 5-10 mm, 50% (n=12) went on to receive a VP shunt, and for fetuses with ventricle sizes 10-15mm, 37.5% (n=8) received a VP shunt postnatally. No significant correlation was found between 3rd and 4thventricular dilatation and postnatal VP shunt placement. Absence of cisterna magna on fetal MRI was found to be a statistically significant predictor (p Conclusions: This study correlated prenatal ventricular size on fetal MRI with potential need for a VP shunt by one year of age. All fetuses with prenatal ventricle size greater than 15 mm required a VP shunt by 1 year of age. The results of this study could be used to help guide the clinician in evaluating prenatal MRIs and in counseling parents