DGN-WP-262 Machine learning for brain atrophy staging in spinocerebellar ataxia type 3: potential for improving MRI use in clinical practice and trials Hannah Baumeister1, Tamara Schaprian2, Philipp Wegner2, Monica Ferreira2,3, David Kuegler2, Marcondes Cavalcante Franca Jr4, Thiago Junqueira Ribeiro de Rezende4, Alberto Rolim Muro Martinez4, Hong Jiang5,6,7, Zhao Chen5, Liao Weihua8, Marcus Grobe-Einsler2,9, Berkan Serdal Can Koyak2,9, Demet Önder2, Bart Van De Warrenburg10, Judith van Gaalen11,12, Alexandra Durr13, Giulia Coarelli13, Matthis Synofzik14,15, Ludger Schöls15,16, Paola Giunti17, Hector Garcia-Moreno17, Gülin Öz18, James Joers18, Dagmar Timmann19, Heike Jacobi20, Jeroen de Vries21, Peter Barker22, Eva-Maria Ratai23,24, Kathrin Reetz25,26, Jon Infante27, Jeannette Hübener28,29, Thomas Klockgether2, David Berron1,30,31, Jennifer Faber2,9,32 1German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Deutschland, 2German Center for Neurodegenerative Diseases (DZNE), Bonn, Deutschland, 3University of Bonn, Bonn, Deutschland, 4Department of Neurology, School of Medical Sciences, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil, 5Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, China, 6Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, Hunan, China, 7National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China, 8Radiological Intervention Center, Department of Radiology, Xiangya Hospital, Central South University, Changsha, Hunan, China, 9Center for Neurology, Department of Parkinson, Sleep and Movement Disorders, University Hospital Bonn, Bonn, Deutschland, 10Department of Neurology, Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Center, Nijmegen, Netherlands, 11Department of Neurology, Radboud University Medical Center, Nijmegen, Netherlands, 12Department of Neurology, Rijnstate Hospital, Arnhem, Netherlands, 13Sorbonne Université, Paris Brain Institute - ICM, Inserm, CNRS, APHP, Pitié-Salpêtrière University Hospital, Paris, France, 14Division Translational Genomics of Neurodegenerative Diseases, Hertie Institute for Clinical Brain Research and Center of Neurology, University of Tübingen, Tübingen, Deutschland, 15German Center for Neurodegenerative Diseases (DZNE), Tübingen, Deutschland, 16Department of Neurology and Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Deutschland, 17Ataxia Centre, Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, United Kingdom, 18Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, United States, 19Department of Neurology and Center for Translational Neuro- and Behavioral Sciences, University Hospital Essen, University of Duisburg-Essen, Essen, Deutschland, 20Department of Neurology, University Hospital Heidelberg, Heidelberg, Deutschland, 21Department of Neurology, University Medical Center Groningen, University of Groningen, Groningen, Netherlands, 22Johns Hopkins University School of Medicine, Baltimore, United States, 23Department of Radiology, Massachusetts General Hospital, Boston, United States, 24A. Martinos Center for Biomedical Imaging and Harvard Medical School Charlestown, Boston, United States, 25Department of Neurology, RWTH Aachen University, Aachen, Deutschland, 26JARA-Brain Institute Molecular Neuroscience and Neuroimaging, Forschungszentrum Jülich, Jülich, Deutschland, 27Neurology Service, University Hospital Marqués de Valdecilla-IDIVAL, Universidad de Cantabria, Centro de Investigación en Red de Enfermedades Neurodegenerativas (CIBERNED), Santander, Spain, 28Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Deutschland, 29Centre for Rare Diseases, University of Tübingen, Tübingen, Deutschland, 30Center for Behavioral Brain Sciences (CBBS), Otto-von-Guericke University Magdeburg, Magdeburg, Deutschland, 31Clinical Memory Research Unit, Department of Clinical Sciences Malmö, Lund University, Lund, Sweden, 32Department of Neuroradiology, University Hospital Bonn, Bonn, Deutschland Background: Spinocerebellar ataxia type 3 (SCA3) is the most common autosomal dominant ataxia worldwide. The dis- ease is characterized by progressive brain atrophy detectable via MRI, with regional volumetric decline emerging even before clinical manifestation. However, the precise sequence in which atrophy occurs in the earliest-affected brain re- gions remains unknown. Objectives: We aimed to establish a staging framework that effectively captures earliest atrophy in SCA3 using MRI. Ex- ploring potential applications, we further assess whether atrophy stage classifications are predictive of ataxia progression and assess their utility for enriching clinical trial samples. 210 98. Kongress der Deutschen Gesellschaft für Neurologie • 12. – 15. November 2025