Automated volumetry of hippocampal subfields in temporal lobe epilepsy

Franz Riederer; René Seiger; Rupert Lanzenberger; Ekateriana Pataraia; Gregor Kasprian; Lars Michels; Spyros Kollias; Thomas Czech; Johannes A Hainfellner; Johannes Beiersdorf; Christoph Baumgartner

doi:10.1016/j.eplepsyres.2021.106692

Automated volumetry of hippocampal subfields in temporal lobe epilepsy

Epilepsy Res. 2021 Sep:175:106692. doi: 10.1016/j.eplepsyres.2021.106692. Epub 2021 Jun 24.

Affiliations

¹ Department of Neurology, Clinic Hietzing & Karl Landsteiner Institute for Clinical Epilepsy Research and Cognitive Neurology, Vienna, Austria; Faculty of Medicine, University of Zurich, Zurich, Switzerland. Electronic address: franz.riederer@uzh.ch.
² Neuroimaging Labs, Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria.
³ Department of Neurology, Medical University of Vienna, Vienna, Austria.
⁴ Department of Radiology and Nuclear Medicine, Medical University of Vienna, Vienna, Austria.
⁵ Clinic of Neuroradiology, University Hospital Zurich, Zurich, Switzerland.
⁶ Department of Neurosurgery, Medical University of Vienna, Vienna, Austria.
⁷ Division of Neuropathology and Neurochemistry, Department of Neurology, Medical University of Vienna, Austria.
⁸ Department of Neurology, Clinic Hietzing & Karl Landsteiner Institute for Clinical Epilepsy Research and Cognitive Neurology, Vienna, Austria.
⁹ Department of Neurology, Clinic Hietzing & Karl Landsteiner Institute for Clinical Epilepsy Research and Cognitive Neurology, Vienna, Austria; Medical Faculty, Sigmund Freud Private University, Vienna, Austria.

PMID: 34175792
DOI: 10.1016/j.eplepsyres.2021.106692

Abstract

Introduction: Hippocampal sclerosis is the most frequent pathological substrate in drug resistant temporal lobe epilepsy (TLE). Recently 4 types of hippocampal sclerosis (HS) have been defined in a task force by the International League Against Epilepsy (ILAE), based on patterns of cell loss in specific hippocampal subfields. Type 1 HS is most frequent and has the most favorable outcome after epilepsy surgery. We hypothesized that volume loss in specific hippocampal subfields determined by automated volumetry of high resolution MRI would correspond to cell loss in histological reports.

Material and methods: In a group of well characterized patients with drug resistant TLE (N = 26 patients, 14 with right-sided focus, 12 with left-sided focus) volumes of the right and left hippocampus and the hippocampal subfields CA1, CA2 + 3, CA4 and dentate gyrus (DG) were estimated automatically using FreeSurfer version 6.0 from high-resolution cerebral MRI and compared to a large group of healthy controls (N = 121). HS subtype classification was attempted based on histological reports.

Results: Volumes of the whole hippocampus and all investigated hippocampal subfields (CA1, CA2 + 3, CA4 and DG) were significantly lower on the ipsilateral compared the contralateral side (p < 0.001) and compared to the healthy controls (p < 0.001). Conversely, whole hippocampal and hippocampal subfield volumes were not significantly different from healthy control values on the contralateral side. In 12 of 20 patients the pattern of hippocampal volume loss in specific subfields was in accordance with HS types from histology. The highest overlap between automated MRI and histology was achieved for type 1 HS (in 10 of 12 cases).

Conclusion: The automated volumetry of hippocampal subfields, based on high resolution MRI, may have the potential to predict the pattern of cell loss in hippocampal sclerosis before operation.

Keywords: Epilepsy surgery; Hippocampal sclerosis; ILEA types; Outcome; Temporal lobe epilepsy.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Atrophy / pathology
Epilepsy, Temporal Lobe* / diagnostic imaging
Epilepsy, Temporal Lobe* / pathology
Epilepsy, Temporal Lobe* / surgery
Hippocampus / pathology
Humans
Magnetic Resonance Imaging
Sclerosis / pathology