OP16.06: Assessing acute fetal brain injury with US and MRI: antenatal imaging and associated risk factors

Abstract

To identify patterns offetal brain injury with US and MRI, and to correlate findings with antenatal risk factors and postnatal outcome. Institutional ethical approval was obtained in order to review records to identify fetuses with evidence of brain injury. Postnatal imaging and postmortem findings were correlated with prenatal sonographic findings. Sonographic evidence of brain injury was documented antenatally in 54 fetuses and confirmed on fetal or postnatal MRI or at autopsy. There was intracranial hemorrhage in 24 (44%), hypoxia-ischemia in 9 (17%), fetal infection in 6 (11%), schizencephaly/stroke in 5 (9%), teratogen exposure in 5 (9%), and periventricular pseudocysts in 5 (9%) associated with other non-CNS anomalies. Aneuploidy was found in 2 fetuses (3.7%). Antenatal risk factors included multiple gestation in 26% of cases (3 dichorionic, 11 monochorionic gestation). Among monochorionic gestations, 3 were related to twin transfusion syndrome and 8 to IUFD. Intracranial hemorrhage was seen in 6 twins, 2 of which were dichorionic. Singletons with hemorrhage (18 cases) were associated with alloimmune thrombocytopenia in 4, metabolic disorder in 2, and CMV in 1; in the remainder, etiology was undetermined. A spectrum of imaging findings in brain hemorrhage included Grade 4 ICH in 6 fetuses, Grade 3 ICH in 7 including one with Dandy-Walker malformation, Grade 2 hemorrhage in 2, Grade 1 ICH in 3; and 3 fetuses with posterior fossa hemorrhage. Two fetuses had focal white matter hemorrhage. Fetal brain injury can be detected sonographically and confirmed with fetal MRI, postnatally, or at autopsy. Knowledge of risk factors and the spectrum of imaging findings can improve antenatal detection of prenatal insults. Specific maternal, fetal, or placental conditions are associated with a higher risk of fetal brain injury and a spectrum of causative pathological entities are involved (ischemia/infarction, hemorrhage, teratogens, infection).