Regional Hippocampal Involvement in Paediatric Multiple Sclerosis: A Radial Mapping MR Study (P2.336)

OBJECTIVE: To assess the patterns of global and regional hippocampal volume (HV) changes in paediatric multiple sclerosis (MS) patients, and their correlations with clinical, neuropsychological and MRI metrics. BACKGROUND: Hippocampal demyelination and neurodegeneration occur early in MS. DESIGN/METHODS: From 53 paediatric MS patients and 18 healthy controls (HC), brain dual-echo and 3DT1-weighted images were acquired. Global HV was computed using a manual tracing procedure. Regional HV changes were assessed using a radial mapping analysis. Patients with abnormal performance in 蠅2 tests of the Brief Neuropsychological Battery for Children were classified as cognitively impaired (CI). Global and regional HV changes were compared between groups and correlated with disease duration, EDSS, BRBC tests scores, T2- and T1-lesion volume (LV), normalized brain (NBV), gray matter (GMV) and white matter volumes (WMV). RESULTS: Global HV was reduced, bilaterally, in patients versus HC (p<0.001), but not significantly correlated with clinical and MRI measures. In patients, radial atrophy affected the cornu Ammonis (CA1), subiculum and dentate gyrus (DG) subfields of both hippocampi, mostly on the right side (p<0.001). Radial hypetrophy of the DG subfield was found in both hippocampi, mostly on the left side. Significant correlations were found between regional HV changes and clinical and MRI metrics. Twenty-one (39.6%) patients were CI. Global HV did not differ between CI versus CP MS patients. Compared to CP patients, CI ones had areas of radial atrophy of the subiculum and DG subfields of the right hippocampus (p<0.001). Significant correlations were found between regional HV changes and memory, attention and language abilities. CONCLUSIONS: Hippocampal subregions have a different vulnerability to MS-related damage, possibly reflecting differential susceptibility to inflammatory insults and neurodegenerative processes of the hippocampal subfields. These results support the feasibility of MR-based radial mapping for the development of reliable markers of disease progression in MS. Study Supported by: a grant from Italian Ministry of Health (GR-2009-1529671)