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276: MRI scoring to predict neurodevelopmental outcomes in survivors of twin-twin transfusion syndrome

      Objective

      Survivors of twin-twin transfusion syndrome (TTTS) carry a 6-18% chance of severe neurodevelopmental impairment due to rapid shifts in blood flow in utero. Magnetic resonance imaging (MRI) is the most sensitive imaging modality for hypoxic ischemic injury. A prior study of 22 TTTS survivors showed 68% of infants had brain injury on postnatal MRI. Woodward et al. created an MRI scoring system that correlates with neurodevelopmental outcomes in very low birth weight infants. Objective of this study is to determine if the Woodward MRI brain injury grading scale correlates with neurodevelopmental impairment in survivors of TTTS.

      Study Design

      This is a prospective cohort study of survivors of TTTS who underwent FLP between 9/2013 and 2/2017. Postnatal brain MRI was scored at term corrected gestational age (CGA, 37 to 44 weeks). The Woodward scoring system has five categories of injury for white matter, and three categories for gray matter. Neurodevelopmental follow up was performed with physical therapy (PT) evaluation at 4 months CGA, and Bayley Scales of Infant Development III (BSID3) at 18 months CGA and 2.5 years of age. Statistical analysis was performed to evaluate the relationship between brain MRI scores and developmental outcomes.

      Results

      To date, 49 infants have been recruited. Only 6/49 (12%) of our cohort had abnormal MRI scores. Infants with abnormal white matter scores were significantly more likely to be born at a later gestational age (35.2 vs 30.6 weeks, p=0.021) and to have an abnormal gross motor score on PT evaluation (-0.75 vs 0.14 months, p=0.015). They also trended toward an abnormal motor score on the first BSID3 (82 vs 96 points, p=0.059). There was no significant correlation between stage of TTTS or gestational age at FLP with the MRI score. A significant percentage of infants had abnormal findings on physical therapy (≥1 month delay, 5/41 (12%)), first BSID3 (≥1SD below average, 6/20 (30%)), and second BSID3 (≥1SD below average, 5/6 (83%); ≥2SD below average, 2/6 (33%)). Results are shown in Table.

      Conclusion

      White matter injury was significantly associated with lower gross motor skills on PT evaluation and trended toward lower motor skills on the BSID3 at 18 months of age. Incidence of brain injury on MRI in TTTS survivors may be far lower than previously suggested, although a high percentage of infants still developed at least mild neurodevelopmental delays.
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