ABSTRACT NUMBER: ESOC2026A1404 ULTRA–HIGH-FIELD MRI FOLLOW-UP IN TRANSIENT GLOBAL AMNESIA WITH DIFFUSION-WEIGHTED LESIONS: A 7-TESLA STUDY

Abstract Background and aims Transient global amnesia (TGA) is a clinically well-defined syndrome, frequently associated with diffusion-weighted imaging (DWI) lesions on conventional MRI. The pathophysiological relevance of these lesions and their long-term structural correlates remain incompletely understood. 7-Tesla MRI offers substantially improved spatial resolution and may provide new insights into residual tissue changes after TGA. Methods We retrospectively screened for patients diagnosed with TGA between July 2024 - July 2025. Eight patients with detectable DWI lesions on routine MRI were identified and invited to undergo follow-up 7-Tesla MRI. Analyses focused on anatomical regions corresponding to the previously detected diffusion-restricted lesions. Results Four patients were female, median age 61 years. On initial MRI, there were 1-3 hippocampal DWI lesions per patient, occurring either unilaterally or bilaterally, without synchronous cerebral infarctions. Median interval between the clinical event and 7-Tesla MRI was 9.6 months. In 50% of patients, no residual structural abnormalities were identified. 2/8 (25%) patients demonstrated persistent focal structural alterations at prior DWI restriction sites, including T2-hyperintense discontinuities of the pyramidal cell layer and focal thinning and indentation of the polymorphic layer. Two further patients (25%) exhibited equivocal residual findings corresponding to the initial DWI lesions, potentially attributable to improved tissue contrast at 7-Tesla MRI, comprising subtle susceptibility-related signal alterations (1/8) and patchy T1-hypointense lesions (1/8) without T2-weighted correlates. Conclusions Our findings suggest heterogeneous underlying mechanisms in TGA, with distinct subgroups showing either transient or persistent structural imaging changes. Further prospective studies are required to clarify their pathophysiological relevance and clinical implications. Conflict of interest Jorge Plümer: nothing to disclose; Aliaksandr Harustovich: nothing to disclose; Omid Nikoubashman: nothing to disclose; W.-R. Schäbitz reports consulting fees from Boehringer Ingelheim, Daiichi Sankyo, Medtronic, and Revelasio; honoraria for lectures, presentations, speakers’ bureaus, manuscript writing, or educational events from Argenx, Biogen, Bristol Myers Squibb, Boehringer Ingelheim, Daiichi Sankyo, Bayer, Pfizer, Medtronic, Novartis, and Ferrer; participation on a Data Safety Monitoring Board or Advisory Board for Revelasio; and serves as Editor-in-Chief of Neurological Research and Practice (Journal of the German Neurological Association).