Spectroscopic magnetic resonance in hemimegalencephalus
Martínez-Bermejo, A.; Pascual-Castroviejo, I.; García-Segura, J.M.; Viaño, J.; López-Martín, V.; Martínez-Fernández, V.; Arcas, J.; Tendero, A.; Gutiérrez, M.
Revista de Neurologia 24(136): 1548-1551
1996
ISSN/ISBN: 0210-0010 PMID: 9064175 Document Number: 459035
Hemimegalencephalus (HM) is a disorder of cerebral migration characterized by the overdevelopment of one cerebral hemisphere. It is usually associated with pachygyria, gliosis and neurone loss. We present a study using stereoscopic magnetic resonance (SMR) in a case of HM confirmed by the pathologist. A girl with right HM had hemigeneralized crisis since birth. A selective right temporoccipital cortectomy was done when she was two and a half years old. The resected piece showed thickening and absence of cortical striation, neurone loss, gliosis, giant neurones and heterotopias. After a symptom-free period the crises reappeared as right fronto-parietal epileptiform anomalies. When she was four years old SMR was done to compare this area with the corresponding area of the radiologically normal left hemisphere. Comparative study showed a marked drop in N-acetyl-aspartate (NAA), glutamate (Glu) and Gaba, and increased choline (Col) and inositol (Ino). We found no difference in the creatinine levels. The histological findings are in concordance with the levels of metabolites found in the affected hemisphere. The drop in NAA and Glu is related to neurone loss and the increase in glial cells, and the increase in Col and Ino with increase in membranes metabolism, as is observed in the gliosis. SMR is an advance in the identification and grading of changes seen on conventional MR, when establishing the prognosis and choice of treatment in HM.