Long-term Mri Follow-up After Gamma Knife Radiosurgery For Temporal Lobe EpilepsyAdyl Melhaoui1, Michael C. Park1, Motohiro Hayashi2, Fabrice Bartolomei1, Patrick Chauvel1, Jean Regis31Department of Stereotactic and Functional Neurosurgery, Timone University Hospital, A.P.M. INSERM U751, Marseille, France 2Tokyo, Japan 3 Keywords: epilepsy, gamma knife, mesial temporal sclerosis, outcome, radiosurgery
Gamma Knife radiosurgery (GKR) for selected cases of refractory mesial temporal lobe epilepsy (MTLE) has proven its long-term safety/efficiency 1.
We assessed and evaluated the correlation between the timing of long-term MRI changes and the clinical outcome.
We reviewed the clinical charts, dose planning and follow-up imaging of 15 patients treated for MTLE at the Timone University Hospital with more than 6 years of follow-up. Between 1993 and 1998, 15 patients (6 males, 9 females, mean age 35, range 22-46) were treated for MTLE with mean follow-up of 8 years (6-11) with total of 155 MRIs (10 MRIs/patient).
We evaluated dates of onset of MR changes and resolution of contrast enhancement, mass effect and long-term lesioning effect. We compared the results of groups based on the Engel classification.
Mean onset of first MRI change was 11.5 months, mean time for maximal change was 15 months, and mean time for MRI resolution was 42 months. In only 60% of patients (9/15), long-term MRI showed a cerebral lesion (mean volume 1.55cc) in the anterio-mesio-temporal area. In patients with a lesion on the MRI, its volume was small and represents only 18% of the treatment volume. In 3 cases (20%), a cystic lesion was identified beyond 100 months. In the best-outcome group (Engel Ia), the mean time of MRI change onset is 12.5 months, maximal change 17 months and the resolution 55 months. In the worst-outcome group (Engel III and IV), the mean time of MRI change onset is 9.3 months, maximal change 14 months and the resolution 29 months. The data suggest more delayed the onset of MRI changes and resolution, better the clinical outcome.
This is a retrospective study.
GKR is an effective and safe treatment for MTLE with 60% of patients being seizure free at long-term follow-up. Delayed onset of MRI changes and resolution is a good predictor of positive clinical outcome.
Long-term MR lesioning is not mandatory for seizure control. Close long-term MRI monitoring is necessary to assess and follow MRI changes and late complications. Project Roles:
A. Melhaoui (), M. Park (), M. Hayashi (), F. Bartolomei (), P. Chauvel (), J. Regis ()