gms | German Medical Science

63rd Annual Meeting of the German Society of Neurosurgery (DGNC)
Joint Meeting with the Japanese Neurosurgical Society (JNS)

German Society of Neurosurgery (DGNC)

13 - 16 June 2012, Leipzig

Presurgical diagnosis of the epileptogenic focus using near-infrared spectroscopy mapping

Meeting Abstract

Search Medline for

  • E. Watanabe - Department of Neurosurgery, Jichi Medical University, Tochigi, Japan
  • H. Yokota - Department of Neurosurgery, Jichi Medical University, Tochigi, Japan
  • K. Oguro - Department of Neurosurgery, Jichi Medical University, Tochigi, Japan

Deutsche Gesellschaft für Neurochirurgie. Japanische Gesellschaft für Neurochirurgie. 63. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC), Joint Meeting mit der Japanischen Gesellschaft für Neurochirurgie (JNS). Leipzig, 13.-16.06.2012. Düsseldorf: German Medical Science GMS Publishing House; 2012. DocMI.06.04

DOI: 10.3205/12dgnc017, URN: urn:nbn:de:0183-12dgnc0172

Published: June 4, 2012

© 2012 Watanabe et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en). You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.


Outline

Text

For drug resistant epilepsy, an accurate diagnosis of the epileptogenic focus is inevitable in order to achieve a good outcome in a surgical intervention. For this purpose, functional mapping techniques such as SPECT and PET are usually applied before surgery. We developed and investigated the feasibility of near-infrared spectroscopy (NIRS) ictal recording as a new functional mapping technique in the presurgical diagnosis of the epileptogenic focus. We used a 48-channel NIRS system (ETG 4000; Hitachi Medical Corporation, Tokyo, Japan) in a conventional mode, and also in a double density mode. Twenty-three patients with drug resistant epilepsy, who were admitted to the Department of Neurosurgery in the Jichi Medical University Hospital for the presurgical evaluation of epilepsy surgery and operated in the period from 2006 to 2010, were included in this study. All these patients were subjected to inter-ictal IMZ SPECT examination. 10 patients were subjected to inter-ictal FDG PET examination. Ictal recordings using NIRS were also applied in 10 patients simultaneously with long-term scalp video-EEG monitoring.

Ictal NIRS showed an increase of regional blood flow in the focus area at the beginning of seizures. We utilized this phenomenon to identify the focus location.

Ictal NIRS diagnosed the side of the epileptogenic focus correctly in 80% of patients which was superior to the inter-ictal IMZ SPECT (correct diagnosis in 47.8%) and inter-ictal FDG PET (correct diagnosis in 50%). Ictal NIRS also showed a higher specificity than that of inter-ictal IMZ SPECT (80% and 47.8% respectively), and a higher sensitivity than that of inter-ictal FDG PET (80% and 50% respectively). These results were much more prominent in patients with neocortical epilepsy, since ictal NIRS diagnosed the side of the epileptogenic focus correctly in all patients (100%) with a specificity and sensitivity of 100%, while inter-ictal IMZ SPECT was diagnostic in 50% of patients with a specificity of 50%, and inter-ictal FDG PET was correctly diagnosed in 33.3% of patients with a sensitivity of 33.3%. Ictal NIRS has also been shown to be superior to inter-ictal IMZ SPECT and inter-ictal FDG PET in the diagnosis of laterality of the epileptogenic focus in patients with normal MRI results (non-lesional epilepsy), as they were diagnostic in 100%, 44.4% and 40% respectively.

These results augment our previous results showing that ictal NIRS is a valuable and reliable method for diagnosing the laterality of the epileptogenic focus especially in patients with neocortical epilepsy and patients with non-lesional epilepsy.