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Volumetric glutamate imaging (GluCEST) using 7T MRI can lateralize nonlesional temporal lobe epilepsy : A preliminary study

Hadar, Peter N ; Kini, Lohith G ; Nanga, Ravi Prakash Reddy ; Shinohara, Russell T ; Chen, Stephanie H ; Shah, Preya ; Wisse, Laura E M LU orcid ; Elliott, Mark A ; Hariharan, Hari and Reddy, Ravinder , et al. (2021) In Brain and Behavior 11(8).
Abstract

INTRODUCTION: Drug-resistant epilepsy patients show worse outcomes after resection when standard neuroimaging is nonlesional, which occurs in one-third of patients. In prior work, we employed 2-D glutamate imaging, Glutamate Chemical Exchange Saturation Transfer (GluCEST), to lateralize seizure onset in nonlesional temporal lobe epilepsy (TLE) based on increased ipsilateral GluCEST signal in the total hippocampus and hippocampal head. We present a significant advancement to single-slice GluCEST imaging, allowing for three-dimensional analysis of brain glutamate networks.

METHODS: The study population consisted of four MRI-negative, nonlesional TLE patients (two male, two female) with electrographically identified left temporal... (More)

INTRODUCTION: Drug-resistant epilepsy patients show worse outcomes after resection when standard neuroimaging is nonlesional, which occurs in one-third of patients. In prior work, we employed 2-D glutamate imaging, Glutamate Chemical Exchange Saturation Transfer (GluCEST), to lateralize seizure onset in nonlesional temporal lobe epilepsy (TLE) based on increased ipsilateral GluCEST signal in the total hippocampus and hippocampal head. We present a significant advancement to single-slice GluCEST imaging, allowing for three-dimensional analysis of brain glutamate networks.

METHODS: The study population consisted of four MRI-negative, nonlesional TLE patients (two male, two female) with electrographically identified left temporal onset seizures. Imaging was conducted on a Siemens 7T MRI scanner using the CEST method for glutamate, while the advanced normalization tools (ANTs) pipeline and the Automated Segmentation of the Hippocampal Subfields (ASHS) method were employed for image analysis.

RESULTS: Volumetric GluCEST imaging was validated in four nonlesional TLE patients showing increased glutamate lateralized to the hippocampus of seizure onset (p = .048, with a difference among ipsilateral to contralateral GluCEST signal percentage ranging from -0.05 to 1.37), as well as increased GluCEST signal in the ipsilateral subiculum (p = .034, with a difference among ipsilateral to contralateral GluCEST signal ranging from 0.13 to 1.57).

CONCLUSIONS: The ability of 3-D, volumetric GluCEST to localize seizure onset down to the hippocampal subfield in nonlesional TLE is an improvement upon our previous 2-D, single-slice GluCEST method. Eventually, we hope to expand volumetric GluCEST to whole-brain glutamate imaging, thus enabling noninvasive analysis of glutamate networks in epilepsy and potentially leading to improved clinical outcomes.

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publishing date
type
Contribution to journal
publication status
published
subject
keywords
Epilepsy, Temporal Lobe/diagnostic imaging, Female, Glutamic Acid, Hippocampus/diagnostic imaging, Humans, Magnetic Resonance Imaging, Male, Neuroimaging
in
Brain and Behavior
volume
11
issue
8
article number
e02134
publisher
John Wiley & Sons Inc.
external identifiers
  • pmid:34255437
  • scopus:85109823867
ISSN
2162-3279
DOI
10.1002/brb3.2134
language
English
LU publication?
no
additional info
© 2021 The Authors. Brain and Behavior published by Wiley Periodicals LLC.
id
72ab8a82-ddd5-43ad-aeea-750c0583e2f5
date added to LUP
2022-05-30 13:33:45
date last changed
2024-06-27 05:25:50
@article{72ab8a82-ddd5-43ad-aeea-750c0583e2f5,
  abstract     = {{<p>INTRODUCTION: Drug-resistant epilepsy patients show worse outcomes after resection when standard neuroimaging is nonlesional, which occurs in one-third of patients. In prior work, we employed 2-D glutamate imaging, Glutamate Chemical Exchange Saturation Transfer (GluCEST), to lateralize seizure onset in nonlesional temporal lobe epilepsy (TLE) based on increased ipsilateral GluCEST signal in the total hippocampus and hippocampal head. We present a significant advancement to single-slice GluCEST imaging, allowing for three-dimensional analysis of brain glutamate networks.</p><p>METHODS: The study population consisted of four MRI-negative, nonlesional TLE patients (two male, two female) with electrographically identified left temporal onset seizures. Imaging was conducted on a Siemens 7T MRI scanner using the CEST method for glutamate, while the advanced normalization tools (ANTs) pipeline and the Automated Segmentation of the Hippocampal Subfields (ASHS) method were employed for image analysis.</p><p>RESULTS: Volumetric GluCEST imaging was validated in four nonlesional TLE patients showing increased glutamate lateralized to the hippocampus of seizure onset (p = .048, with a difference among ipsilateral to contralateral GluCEST signal percentage ranging from -0.05 to 1.37), as well as increased GluCEST signal in the ipsilateral subiculum (p = .034, with a difference among ipsilateral to contralateral GluCEST signal ranging from 0.13 to 1.57).</p><p>CONCLUSIONS: The ability of 3-D, volumetric GluCEST to localize seizure onset down to the hippocampal subfield in nonlesional TLE is an improvement upon our previous 2-D, single-slice GluCEST method. Eventually, we hope to expand volumetric GluCEST to whole-brain glutamate imaging, thus enabling noninvasive analysis of glutamate networks in epilepsy and potentially leading to improved clinical outcomes.</p>}},
  author       = {{Hadar, Peter N and Kini, Lohith G and Nanga, Ravi Prakash Reddy and Shinohara, Russell T and Chen, Stephanie H and Shah, Preya and Wisse, Laura E M and Elliott, Mark A and Hariharan, Hari and Reddy, Ravinder and Detre, John A and Stein, Joel M and Das, Sandhitsu and Davis, Kathryn A}},
  issn         = {{2162-3279}},
  keywords     = {{Epilepsy, Temporal Lobe/diagnostic imaging; Female; Glutamic Acid; Hippocampus/diagnostic imaging; Humans; Magnetic Resonance Imaging; Male; Neuroimaging}},
  language     = {{eng}},
  number       = {{8}},
  publisher    = {{John Wiley & Sons Inc.}},
  series       = {{Brain and Behavior}},
  title        = {{Volumetric glutamate imaging (GluCEST) using 7T MRI can lateralize nonlesional temporal lobe epilepsy : A preliminary study}},
  url          = {{http://dx.doi.org/10.1002/brb3.2134}},
  doi          = {{10.1002/brb3.2134}},
  volume       = {{11}},
  year         = {{2021}},
}