[11C]-Methionine PET: dysembryoplastic neuroepithelial tumours compared with other epileptogenic brain neoplasms
- D S Rosenberg1,
- G Demarquay1,
- A Jouvet2,
- D Le Bars3,
- N Streichenberger2,
- M Sindou4,
- N Kopp2,
- F Mauguière1,
- P Ryvlin1,3
- 1Department of Functional Neurology and Epileptology, Hopital Neurologique, Lyon, France
- 2Department of Neuropathology, Hopital Neurologique, Lyon, France
- 3CERMEP, Hopital Neurologique, Lyon, France
- 4Department of Neurosurgery, Hopital Neurologique, Lyon, France
- Correspondence to: Professor Ryvlin Cermep, Hopital Neurologique, 59 Bd Pinel, Lyon, 69003, France;
- Received 10 August 2004
- Accepted 2 May 2005
- Revised 29 April 2005
Background and objectives: Brain tumours responsible for longstanding partial epilepsy are characterised by a high prevalence of dysembryoplastic neuroepithelial tumour (DNT), whose natural evolution is much more benign than that of gliomas. The preoperative diagnosis of DNT, which is not yet feasible on the basis of available clinical and imaging data, would help optimise the therapeutic strategy for this type of tumour. This study tested whether [11C]-methionine positron emission tomography (MET-PET) could help to distinguish DNTs from other epileptogenic brain tumours.
Methods: Prospective study of 27 patients with partial epilepsy of at least six months duration related to a non-rapidly progressing brain tumour on magnetic resonance imaging (MRI). A structured visual analysis, which distinguished between normal, moderately abnormal, or markedly abnormal tumour methionine uptake, as well as various regions of interest and semiquantitative measurements were conducted.
Results: Pathological results showed 11 DNTs (41%), 5 gangliogliomas (18%), and 11 gliomas (41%). MET-PET visual findings significantly differed between the various tumour types (p<0.0002), regardless of gadolinium enhancement on MRI, and were confirmed by semiquantitative analysis (p<0.001 for all calculated ratios). All gliomas and gangliogliomas were associated with moderately or markedly increased tumour methionine uptake, whereas 7/11 DNTs had a normal methionine uptake, including all six located in the mesiotemporal structures. No DNT presented with a marked MET-PET abnormality.
Conclusion: Normal MET-PET findings in patient with an epileptogenic and non-rapidly progressing brain tumour are suggestive of DNT, whereas a markedly increased tumour methionine uptake makes this diagnosis unlikely.
- DNT, dysembryoplastic neuroepithelial tumour
- T/C, tumour-to-contralateral homotopic ratio
- MET-PET, [11C]-methionine positron emission tomography
- MRI, magnetic resonance imaging
- OR, tumour-to-contralateral occipital ratio
- ROI, region of interest
- epileptogenic brain tumours
- positron emission tomography
- dysembryoplastic neuroepithelial tumor
Competing interests: none declared
This study was approved by the CCPPRB local ethic committee (Comité Consultatif de Protection des Personnes se prêtant à des Recherches Biomédicales—Centre Léon Bérard, Lyon)