Correction of cerebrospinal fluid levels and brain growth demonstrated by serial fetal magnetic resonance imaging following

Abstract

DEMONSTRATED BY SERIAL FETAL MAGNETIC RESONANCE IMAGING FOLLOWING ENRICO DANZER, MARK P. JOHNSON, MICHAEL BEBBINGTON, R. DOUGLAS WILSON, LARISSA BILANIUK, ERIN SIMON, ALAN FLAKE, LESLIE SUTTON, N. SCOTT ADZICK, Children’s Hospital of Philadelphia, Center for Fetal Diagnosis & Treatment, Philadelphia, Pennsylvania, Children’s Hospital of Philadelphia, Department of Radiology, Philadelphia, Pennsylvania, Children’s Hospital of Philadelphia, Pediatric Neurosurgery, Philadelphia, Pennsylvania OBJECTIVE: Physiological levels of cerebrospinal fluid (CSF) may influence brain growth and maturation during fetal development. Fetuses with myelomeningocele (MMC) have diminished extra-axial CSF levels and altered brain growth. We evaluated extra-axial CSF levels and brain growth following fetal MMC repair by serial assessment of brain morphometry using ultrafast MRI. STUDY DESIGN: Axial measurements were taken at defined anatomical landmarks and in utero repaired MMC fetuses (n = 35) were compared to cohorts of age-matched control fetuses (prenatal = 18, postnatal = 9) and MMC fetuses that underwent postnatal repair (prenatal = 9, postnatal = 22). The brain/ventricular ratio was calculated as transverse diameter of the brain at the level of the atria divided by mean ventricular diameter. RESULTS: In fetuses with MMC, initial MRI scans showed significant cerebellar herniation and almost complete absence of extra-axial and posterior fossa CSF. In utero repair fetuses showed significant reversal of hindbrain herniation. In fetuses with postnatal MMC repair, CSF levels remained low. No differences in postnatal extra-axial CSF levels were found between normal and in utero MMC repaired newborns. The mean increase in ventricular diameter after fetal MMC repair was 33.9% compared to 71.6% in the cohorts of MMC fetuses that underwent postnatal repair. The mean mantle-thickness at the level of atria increased by 28.5 mm (141.8%) in the fetal repair group, by 32.1mm (191.5%) in the control group and by 24 mm (105.3%) in the postnatal repair group cohorts. The mean increase in brain/ventricular ratio after fetal repair was 36.8%, in normal controls 53.1% and 10.4% in postnatal repaired MMC cohorts. CONCLUSION: Midgestational MMC repair results in reestablishment of the extra-axial CSF space. Normalization of CSF volume in the posterior fossa reflects reversal of hindbrain herniation. Increases in mantle thickness and brain/ ventricular ratio suggest increased brain growth in fetuses following in utero repair.