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AJNR - American Journal of Neuroradiology

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American Journal of Neuroradiology 28:1071-1075, June-July 2007
DOI 10.3174/ajnr.A0511
© 2007 American Society of Neuroradiology

BRAIN

Multivoxel Proton MR Spectroscopy in Malformations of Cortical Development

C.C. Leite^a, L.T. Lucato^a, J.R. Sato^b, K.D. Valente^c and M.C.G. Otaduy^a

^a Department of Radiology, University of São Paulo School of Medicine, São Paulo, Brazil
^b Institute of Mathematics and Statistics, University of São Paulo, São Paulo, Brazil
^c Department of Psychiatry, University of São Paulo School of Medicine, São Paulo, Brazil

Please address correspondence to Claudia da Costa Leite, MD, Rua Mário Amaral 81, apto 121 M, São Paulo, São Paulo, Brazil CEP 04002–020; e-mail: claudia.leite{at}hcnet.usp.br

BACKGROUND AND PURPOSE: Malformations of cortical development (MCD) are traditionally considered as a cause of epilepsy. Our aim was to study patients with focal MCD, by using multivoxel proton MR spectroscopy; we focused not only on the lesion but also on the normal-appearing contralateral side (NACS). Our hypothesis was that the metabolic abnormality extends to the NACS; therefore, it would be inadequate to consider NACS as an internal control.

MATERIALS AND METHODS: We studied 16 patients with focal MCD. MR spectroscopy was performed by using a point-resolved spectroscopy sequence technique, including the MCD area and the NACS. In each volume of interest, a smaller volume of interest of 2.25 cm³ centered on the MCD was selected to study the N-acetylaspartate/creatine (NAA/Cr) ratio. In NACS, this ratio was studied by placing a symmetric voxel in comparison with the smaller MCD volume of interest. A control group (n = 30) was also studied to evaluate both white and gray matter by using the same MR spectroscopy protocol.

RESULTS: From 16 analyzed volumes of interest with MCD, 9 were composed of gray matter heterotopia and 7 of cortical dysplasia. MR spectroscopy of both MCD lesions and NACS (n = 10) showed decreased NAA/Cr compared with that of the control group. NACS in these patients did not present significant differences regarding NAA/Cr in comparison with the affected side.

CONCLUSIONS: MR spectroscopy demonstrated abnormal NAA/Cr in both MCD lesions and NACS in patients harboring focal MCD, giving support to the hypothesis that in MCD metabolic abnormalities extend far away from the limits of the lesion, reaching the contralateral side.