Abstract TMP109: Cortico-Ponto-Cerebellar Structural Connectivity in Perinatal Stroke

Abstract

Introduction: Perinatal stroke (PS) causes hemiparetic cerebral palsy and lifelong disability. As an early cerebrovascular injury, typically involving injury to motor systems, PS represents an ideal model for understanding motor system development. Emerging models demonstrate widespread network alterations but the role of the cerebellum is poorly defined. We used diffusion tractography to explore the development of the cortico-ponto-cerebellar (CPC) tract in children with PS, hypothesizing an association between non-dominant CPC diffusion metrics and motor ability. Methods: Retrospective, population-based, cross-sectional, controlled study. Participants aged 6-19 years with unilateral MRI confirmed perinatal arterial ischemic stroke (AIS; n=11) or periventricular venous infarction (PVI; n=20), and typically developing controls (TDC; n=31) had a 3T MRI including T1-weighted and diffusion imaging (32 directions; b=750s/mm 2 , 3 b0 volumes). Probabilistic tensor-based tractography was performed using the posterior limb of the internal capsule and contralateral middle cerebellar peduncle as regions of interest for seeding. Tensor-based outcomes were calculated including mean diffusivity (MD) and fractional anisotropy (FA). An asymmetry index (AI) was subsequently calculated (dominant / non-dominant values). PS participants completed motor assessments [Assisting Hand Assessment (AHA), Melbourne Assessment (MA), Box and Blocks Test (BBT)]. Results: Paired-samples t-tests revealed MD was significantly higher for non-dominant versus dominant tracts across all groups (all p<0.001), while FA did not differ (all p>0.05). MD AI differed among groups (F(2,59)=10.117, p <0.001) such that MD AI was significantly lower (less symmetrical) in AIS (AI=0.912±0.04) compared to PVI (AI=0.960±0.05, p =0.01) and TDC (AI=0.977±0.03, p <0.001). FA AI did not differ between groups (F(2,59)=1.045, p =0.358). A positive association was observed between MD AI and BBT performance in the affected hand (r=0.439, p =0.019). Conclusion: CPC tractography in children with PS is feasible. Development of the CPC appears to be altered following perinatal stroke, the degree of which may relate to motor function.