IMGP-03. Impact of Childhood Cerebellar Tumor Surgery on White Matter Integrity in adulthood: Insights from Automated Tract Segmentation

BACKGROUND Although patients with childhood cerebellar pilocytic asytrocytomas (CCPA) demonstrate favorable survival rates, long-term cognitive and behavioral impairments are frequently observed. While some studies have already identified short-term functional brain alterations in mixed patient cohorts, research focusing on the structural connectivity in CCPA is missing. Therefore, we aimed to investigate the white matter tracts in adults who underwent resection of a cerebellar pilocytic astrocytoma in childhood. METHODS Thirteen patients with CCPA who underwent 3 Tesla magnetic resonance imaging (MRI) in average 15 years after resection and 13 age- and sex-matched healthy controls were enrolled in this study. Cortical thickness (CT) and volume of brain regions were quantified using Freesurfer. Automated tract segmentation was conducted with TractSeg based on probabilistic tractography. Data preprocessing was carried out using MRtrix3 and FSL. RESULTS The left (p = 0.023) and right (p = 0.049) lingual gyrus and the right anterior cingulate (p = 0.016) showed increased CT in patients compared to controls. Additionally, the volume of the left parahippocampal gyrus was significantly greater in the patient group (p = 0.033), whereas a reduction in the volume of the left precentral gyrus was observed (p = 0.027).Tractography analysis revealed significantly reduced fractional anisotropy (FA) values in left and right superior cerebellar peduncle and middle cerebellar peduncle (p < 0.001) in patients. Conversely, increased FA values were observed in the left cingulate tract (p < 0.001). CONCLUSION Our study revealed the first comprehensive long-term structural brain alterations in patients following resection of CCPA, including changes in cortical morphology and white matter integrity. These findings give mechanistic insights into the long-term impact on cognition of surgery for CCPA, thereby opening the avenue for imaging surrogates on cognitive outcome.