Article Text

Download PDFPDF
Seizure outcome after epilepsy surgery in patients with normal preoperative MRI
  1. K Chapman1,
  2. E Wyllie2,
  3. I Najm2,
  4. P Ruggieri4,
  5. W Bingaman3,
  6. J Lüders3,
  7. P Kotagal2,
  8. D Lachhwani2,
  9. D Dinner2,
  10. H O Lüders2
  1. 1Department of Neurology, Baylor College of Medicine, Houston, Texas, USA
  2. 2Departments of Neurology, The Cleveland Clinic Foundation, Cleveland, Ohio, USA
  3. 3Departments of Neurosurgery, The Cleveland Clinic Foundation
  4. 4Departments of Neuroradiology, The Cleveland Clinic Foundation
  1. Correspondence to:
 Dr Elaine Wyllie
 The Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195, USA;


Objective: To determine outcome after epilepsy surgery in patients with normal preoperative magnetic resonance imaging (MRI).

Methods: 24 adult and paediatric patients with normal preoperative MRIs were studied. They underwent epilepsy surgery between 1994 and 2001 and had at least one year of follow up.

Results: At the most recent follow up, nine patients (37%) were seizure-free and 18 (75%) had at least a 90% reduction in seizure frequency with weekly or monthly seizures. Seizure freedom was not significantly different after resections in frontal (5/9) or temporal regions (4/13) (p = 0.24, Fisher’s exact test), or among patients with or without localising features on EEG, PET, or ictal SPECT. Subdural grids, used in 15 of 24 patients, helped tailor resections but were not associated with differences in outcome. Histopathology showed cortical dysplasia in 10 patients (42%), non-specific findings in 13 (54%), and hippocampal sclerosis in one (4%). Cortical dysplasia was seen in seven patients with frontal resection (78%) and non-specific findings in nine (69%) with temporal resection. Seizure outcome did not differ on the basis of location of resection or histopathology.

Conclusions: While these results were less favourable than expected for patients with focal epileptogenic lesions seen on MRI, they represented worthwhile improvement for this patient population with high preoperative seizure burden. In this highly selected group, no single test or combination of tests further predicted postoperative seizure outcome.

  • FLAIR, fluid attenuation recovery
  • MPRAGE, magnetisation prepared rapid gradient echo
  • SPECT, single photon emission computed tomography
  • epilepsy surgery
  • MRI
  • seizure outcome

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.


  • Competing interests: none declared