Abstract 17283: The Impact of Fetal Congenital Heart Disease on In Vivo Regional Brainstem Development

Abstract

Introduction: Brain injury and delayed brain development have been reported in fetuses with congenital heart disease (CHD). While reduced volumes of fetal brain structures have been discovered, the shape alternations of the brainstem affected by CHD were not fully investigated. Hypothesis: We assessed the hypothesis that the morphology of the brainstem in CHD fetuses was altered when compared to healthy controls. Methods: A total of 146 pregnant women were recruited for this longitudinal observational study (99 controls and 47 CHD; median gestational age (GA) and range: 33.4 [24.4-39.1] weeks), in which 207 MRI scans were performed. Single shot fast spin echo T2-weighted images were acquired on a 1.5T GE MRI scanner. Anatomical landmarks of brainstem were manually identified on 1 mm 3 isotropic 3D reconstructed images using RView software. Anterior-posterior and transverse diameters of mesencephalon, pons, and medullary were determined based on 12 landmarks on the midsagittal and coronal planes correspondingly. The inter-landmark distances and 2D areas enclosed by landmarks on the midsagittal plane of the two groups were analyzed using generalized estimating equations, adjusting for GA and fetal gender. Results: Results indicated lower regional anterior-posterior diameters of the pons in CHD fetuses [landmarks 2-3, 2-6, 3-4, and 4-6 ( p-values <0.05)]. The 2D areas enclosed by landmarks on the midsagittal plane were overall smaller in CHD fetuses (control: 183±10 mm 2 ; CHD: 175±10 mm 2 ; p =0.016). No differences in transverse diameters were observed between control and CHD fetuses on the three coronal planes. All measured diameters and areas were significantly increased with advancing GA ( p-values <0.05), while no gender differences were detected. Conclusions: We report for the first time impaired regional growth of the pons in fetuses with CHD. The pons may play a role in altered emerging cerebral-cerebellar structure and functional connections in fetal CHD.