Epileptogenic brain lesions in children: the added-value of combined diffusion imaging and proton MR spectroscopy to the presurgical differential diagnosis.
OBJECTIVE
Focal cortical dysplasia (FCD), dysembryoplastic neuroepithelial tumors (DNTs), and gangliogliomas (GGs) share many clinical features, and the presurgical differential diagnosis of these lesions using conventional magnetic resonance imaging (MRI) is challenging in some cases. The purpose of this work was thus to evaluate the capacity of diffusion-weighted imaging (DWI) and proton magnetic resonance spectroscopy (MRS) to distinguish each lesion from the others.


METHODS
Seventeen children (mean age 9.0 ± 4.7 years), who had been referred for epilepsy associated with a brain tumor and operated, were selected. Preoperative MRI examinations were performed on a 1.5 T system and included anatomical images [T2-weighted, fluid-attenuated inversion recovery (FLAIR) and T1 pre- and post-injection images] as well as DWI and MRS [echo time (TE) = 30 and 135 ms]. Apparent diffusion coefficient (ADC) values were calculated in the lesion and healthy control. MRS relative quantification consisted in normalizing each metabolite by the sum (S) of all metabolites (S(TE=135 ms) = NAA+Cr+Cho; S(TE=30 ms) = NAA+Cr+Cho+Glx+mI). Univariate and multivariate analyses were performed in order to determine which criteria could differentiate the different epileptogenic brain lesions.


RESULTS
When taken alone, none of the MRI parameters was able to distinguish each disease from the others. Conventional MRI failed classifying two patients. When adding ADC to the linear discriminant analysis (LDA), one patient was still misclassified. Complete separation of the three groups was possible when combining conventional MRI, diffusion, and MRS either at long or short TE.


CONCLUSIONS
This study shows the added-value of multimodal MRI and MRS in the presurgical diagnosis of epileptogenic brain lesions in children.
Centre de Résonance Magnétique Biologique et Médicale, Aix-Marseille University/CNRS, Marseille, France. slim.fellah@univmed.fr
Slim
S
Fellah
Virginie
V
Callot
Patrick
P
Viout
Sylviane
S
Confort-Gouny
Didier
D
Scavarda
Philippe
P
Dory-Lautrec
Dominique
D
Figarella-Branger
Patrick J
PJ
Cozzone
Nadine
N
Girard
D000293:Adolescent; D001927:Brain Diseases / Q000150:complications / Q000175:diagnosis*; D001932:Brain Neoplasms / Q000150:complications / Q000175:diagnosis*; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D004827:Epilepsy / Q000175:diagnosis / Q000209:etiology; D006801:Humans; D007223:Infant; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D054220:Malformations of Cortical Development / Q000150:complications / Q000175:diagnosis*; D065703:Malformations of Cortical Development, Group I; D011522:Protons
D011522:Protons