Full-Length Original Research
7T MR spectroscopic imaging in the localization of surgical epilepsy
Article first published online: 29 JUL 2013
Wiley Periodicals, Inc. © 2013 International League Against Epilepsy
Volume 54, Issue 9, pages 1668–1678, September 2013
How to Cite
Pan, J. W., Duckrow, R. B., Gerrard, J., Ong, C., Hirsch, L. J., Resor, S. R., Zhang, Y., Petroff, O., Spencer, S., Hetherington, H. P. and Spencer, D. D. (2013), 7T MR spectroscopic imaging in the localization of surgical epilepsy. Epilepsia, 54: 1668–1678. doi: 10.1111/epi.12322
- Issue published online: 6 SEP 2013
- Article first published online: 29 JUL 2013
- Manuscript Accepted: 13 JUN 2013
- NIH. Grant Numbers: EB011639, EB009871, NS054038
- Swebilius Foundation
- Localization-related epilepsy;
- Spectroscopic imaging;
- Seizure localization;
With the success that surgical approaches can provide for localization-related epilepsy, accurate seizure localization remains important. Although magnetic resonance (MR) spectroscopy has had success in earlier studies in medial temporal lobe epilepsy, there have been fewer studies evaluating its use in a broader range of localization-related epilepsy. With improvements in signal-to-noise with ultra-high field MR, we report on the use of high resolution 7T MR spectroscopic imaging (MRSI) in 25 surgically treated patients studied over a 3.5-year period.
Patients were included in this analysis if the region of MRSI study included the surgical resection region. Concordance between region of MRSI abnormalities and of surgical resection was classified into three groups (complete, partial, or no agreement) and outcome was dichotomized by International League Against Epilepsy (ILAE) I–III and IV–VI groups. MRSI was performed with repetition time/echo time 1.5 s/40 msec in two-dimensional (2D) or three-dimensional (3D) encoding for robust detection of singlets N-acetyl aspartate (NAA), creatine (Cr), and choline with abnormalities in NAA/Cr determined with correction for tissue content of gray matter.
The concordance between MRSI-determined abnormality and surgical resection region was significantly related to outcome: Outcome was better if the resected tissue was metabolically abnormal. All 14 patients with complete resection of the region with the most severe metabolic abnormality had good outcome, including five requiring intracranial electroencephalography (EEG) analysis, whereas only 3/11 without complete resection of the most severe metabolic abnormality had good outcome (p < 0.001).
This is consistent with the seizure-onset zone being characterized by metabolic dysfunction and suggests that high resolution MRSI can help define these regions for the purposes of outcome prediction.