Abstract TMP60: Contralesional Brain Regions Mirror the Volume Changes of Their Homologous Counterparts in the Ipsilesional Hemisphere in Children During the First Year After Unilateral Intracerebral Hemorrhage

Abstract

Introduction: Structural changes following intracerebral hemorrhage (ICH) caused by ruptured brain vascular malformations (VMs) remain poorly understood. We conducted a longitudinal study to examine changes across ipsilesional and contralesional hemispheres after unilateral ICH, mainly in the temporoparietal area. Methods: Brain MRI was acquired in 8 patients aged 8-18 years ( Mean =15.13, SD =3.18) at presentation of ICH prior to treatment (baseline/Session 1) and repeated at 6 months (Session 2) and 12 months (Session 3) post-treatment. Using FreeSurfer 7.4.0, T1 and T2 FLAIR MR images were segmented into cortical and subcortical regions, with gray matter (GM) parcellated based on the DKT atlas. SynthSeg refined lesion extraction for more precise measurements of brain volume. Volume changes were quantified as percent change from baseline with signed values denoting increase or decrease. Pearson correlation and permutation testing ( n =5000) evaluated associations of homologous versus non-homologous regions. Results: There were significant correlations between the volume changes of homologous GM regions, for both Session 2 ( R =0.57, p <0.001) and Session 3 ( R =0.50, p <0.001), and of homologous GM in hemispheric lobes (Session 2: R =0.69, p <0.001; Session 3: R =0.67, p <0.001). Permutation tests confirmed that correlations of volume changes were greater for homologous than non-homologous regions and lobes for Sessions 2 and 3 ( p <0.001 except Session 3 lobes: p =0.016). Conclusions: We observed structural covariance of volume changes between homologous regions, most pronounced in the first 6 months after unilateral ICH. This indicates network-mediated distant effects of ICH, with atrophy reflected by diaschisis and volume recovery mirrored by positive neuroplasticity of contralateral homologs. Lesion-network mapping with correlation to long-term outcome would elucidate the effects of this long-range neuroplasticity following pediatric ICH.