Investigating Dual Pathology: The Prevalence of Hippocampal Volume Loss in Patients with Drug-Resistant Epilepsy
Abstract number :
2.207
Submission category :
5. Neuro Imaging / 5A. Structural Imaging
Year :
2023
Submission ID :
694
Source :
www.aesnet.org
Presentation date :
12/3/2023 12:00:00 AM
Published date :
Authors :
Presenting Author: Alexandrea Kilgore-Gomez, BS – National Institutes of Health
Bijal Patel, MD – National Institutes of Health; Elena Hayday, BS – National Institutes of Health; Tianxia Wu, PhD – National Institutes of Health; Shareena Rahman, MD – National Institutes of Health; William Theodore, MD – National Institutes of Health; Sara Inati, MD – National Institutes of Health
Rationale: Dual pathology (DP), defined as the simultaneous presence of hippocampal sclerosis (HS) and an independent secondary pathology, is relatively common in drug resistant focal epilepsy (DRE) [1]. HS occurs in isolation but also in association with neocortical abnormalities. On magnetic resonance imaging (MRI), HS is characterized by volume loss and FLAIR hyperintensity. More subtle hippocampal volume loss can be a marker of hippocampal damage [2]. Here, we investigate the prevalence of hippocampal volume (HV) loss in patients with DRE and its co-occurrence with independent brain lesions on MRI.
Methods: We retrospectively identified all patients with focal DRE undergoing presurgical evaluation at the NIH Clinical Center from 2004 to 2023 and forty-six healthy volunteers with analyzable structural MR images. Clinical information and radiologic diagnosis of MTS was obtained from the medical record. T1-weighted images were used as inputs to the standard FreeSurfer processing pipeline to generate total brain and hippocampal volumes. HVs were normalized to total brain volume and adjusted for sex. HV loss was defined as normalized HV two standard deviations below the healthy volunteer HV mean for each side. Fisher's exact test was used to test the association between HV loss and MTS findings.
Results: We identified 256 DRE patients and 46 healthy volunteers. Ipsilateral HV loss and MTS were significantly associated (P < 0.0001). MTS was diagnosed in 66/256 patients (26%) (right 22, left 44, bilateral 6). Of these, 23/66 (35%) had contralateral HV loss; 19/66 (29%) had extrahippocampal lesions. Of the 15/256 patients (6%) with HV loss without definite radiographic MTS (right 7, left 5, bilateral 3), 11/15 had extrahippocampal lesions (73%). Of 12 patients with unilateral HV loss, eight had ipsilateral temporal extrahippocampal lesions, one had ipsilateral hippocampal malrotation, one had bilateral hippocampal cystic changes and a contralateral temporal lesion, and two had normal MRIs. Three patients with bilateral HV loss had right parietal gliosis, left frontal gliosis, and diffuse brain atrophy.
Neuro Imaging