Abstracts

Chemical Exchange Saturation Transfer Imaging for Preoperative Assessment in Drug-resistant Focal Epilepsy

Abstract number : 1.376
Submission category : 5. Neuro Imaging / 5B. Functional Imaging
Year : 2024
Submission ID : 878
Source : www.aesnet.org
Presentation date : 12/7/2024 12:00:00 AM
Published date :

Authors :
Presenting Author: Yosuke Ito, MD, PhD – Department of Functional Neurosurgery, Epilepsy Center, NHO Nishiniigata Chuo Hospital

Masafumi Fukuda, MD – NHO Nishiniigata Chuo Hospital
Ken Ono, Ph.D. – Center for Integrated Human Brain Science, Niigata University
Tomoyoshi Ota, M.D. – NHO Nishiniigata Chuo Hospital
Masaki Watanabe, Ph.D. – Center for Integrated Human Brain Science, Niigata University
Tsuyoshi Matsuda, Ph.D. – Division of Ultrahigh Field MRI, Institute for Biomedical Sciences, Iwate Medical University
Masahiro Hatakeyama, M.D., Ph.D. – Center for Integrated Human Brain Science, Niigata University
Hiroshi Masuda, M.D., Ph.D. – NHO Nishiniigata Chuo Hospital
Hiroki Kitaura, M.D., Ph.D. – Department of Neurosurgery, Brain Research Institute, Niigata University
Akiyoshi Kakita, M.D., Ph.D. – Department of Pathology, Brain Research Institute, Niigata University
Makoto Oishi, M.D., Ph.D. – Brain Research Institute, University of Niigata
Hironaka Ikarashi, M.D., Ph.D. – Center for Integrated Human Brain Science, Niigata University

Rationale: The chemical exchange saturation transfer (CEST) method enables the measurement of compounds within an organism. It has been posited that sustained elevations in extracellular glutamate (Glu) levels within astrocytes may precipitate epileptic seizures. Herein, CEST imaging measured the brain glutamate concentration in a patient who underwent focal resection surgery following chronic intracranial electroencephalography.


Methods: A man in his 20s diagnosed with drug-resistant focal epilepsy visited our hospital to receive preoperative assessment. Before the surgical intervention, CEST imaging was measured using an ultra-high field (7 Tesla) MRI system. The study was conducted by comparing the sites of elevated glutamate in CEST imaging with the onset of seizures in intracranial EEG.




Results: Magnetic resonance imaging (MRI) revealed no conspicuous abnormalities; fluorodeoxyglucose-positron emission tomography (FDG-PET) revealed reduced glucose metabolism in the distal portion of the left temporal lobe (Fig.1). As video-electroencephalography (EEG) monitoring, single photon emission tomography (SPECT), and psychological findings did not reveal any regions of epileptic foci, intracranial electrode implantation was performed. Video-EEG monitoring using intracranial electrodes resulted in confirmation of seizure onset in the left anterior temporal lobe. The patient underwent left anterior temporal lobectomy including the regions and preserved the hippocampus. Despite recurrence of focal awareness seizures (FASs) 4 month after surgery, focal impaired awareness seizures have disappeared until 1 year after surgery. CEST imaging delineated an elevation in glutamine concentration extending from the distal tip of the left temporal lobe to the medial temporal lobe (Fig.2A). Those areas included the seizure onset on the intracranial EEG. They were also included in the resection area (Fig.2B). Elevated glutamate levels were observed in the hippocampal head. This finding was suspected to be associated with residual FASs.


Conclusions: These findings suggest that CEST imaging of glutamate concentration may serve as a noninvasive means to estimate epileptogenicity during preoperative assessment in patients with drug-resistant epilepsy, particularly when no apparent abnormalities are evident on head MRI.




Funding: This work was supported by MHLW Research program on rare and intractable diseases, Grant number JPMH23FC1013.

Neuro Imaging