Low-grade gliomas and focal cortical developmental malformations: differentiation with proton MR spectroscopy.
OBJECTIVE
To assess proton magnetic resonance (MR) spectroscopy in differentiating between low-grade gliomas and focal cortical developmental malformations (FCDMs).


METHODS
Eighteen patients with seizures and a cortical brain lesion on MR images were studied with proton MR spectroscopy. A metabolite ratio analysis was performed, and the metabolite signals in the lesion core were compared with those in the contralateral centrum semiovale and in the corresponding brain sites in 18 control subjects to separately obtain the changes in N-acetylaspartate (NAA), choline-containing compounds (Cho), and creatine-phosphocreatine (Cr). Ten patients had a low-grade glioma (three, oligodendrogliomas; three, oligoastrocytomas; three, astrocytomas; and one, pilocytic astrocytoma), and eight had FCDM (five, focal cortical dysplasias and three, dysembryoplastic neuroepithelial tumors). Linear discriminant analysis and Student t test were used for statistical comparisons.


RESULTS
Loss of NAA and increase of Cho were more pronounced in low-grade gliomas than in FCDMs (NAA, -72% +/- 15 [+/- SD] vs -29% +/- 22, P <.001; Cho, 117% +/- 56 vs 21% +/- 66, P <.01). Changes in NAA and Cho helped differentiate low-grade gliomas from FCDMs, and changes in Cho and Cr helped differentiate astrocytomas from oligodendrogliomas and oligoastrocytomas. Metabolite NAA/Cho and NAA/Cr ratios helped differentiate low-grade gliomas from FCDMs but did not differentiate glioma subtypes.


CONCLUSIONS
MR spectroscopy allows distinction between low-grade gliomas and FCDMs and between low-grade glioma subtypes. Metabolite changes are more informative than are metabolite ratios.
Vuori
Kim
K
Department of Radiology, Haartman Institute, Helsinki University Central Hospital, Haartmaninkatu 4, PO Box 180, 00029 Helsinki, Finland. kim.vuori@oriola.com
Kankaanranta
Leena
L
Häkkinen
Anna-Maija
AM
Gaily
Eija
E
Valanne
Leena
L
Granström
Marja-Liisa
ML
Joensuu
Heikki
H
Blomstedt
Göran
G
Paetau
Anders
A
Lundbom
Nina
N
D000293:Adolescent; D000328:Adult; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000032:analysis; D001254:Astrocytoma / Q000175:diagnosis*; D002540:Cerebral Cortex / Q000002:abnormalities* / Q000473:pathology; D002648:Child; D002794:Choline / Q000032:analysis; D003401:Creatine / Q000032:analysis; D003937:Diagnosis, Differential; D004828:Epilepsies, Partial / Q000175:diagnosis / Q000473:pathology; D005260:Female; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D018242:Neuroectodermal Tumors, Primitive / Q000175:diagnosis*; D009837:Oligodendroglioma / Q000175:diagnosis*; D010725:Phosphocreatine / Q000032:analysis; D012680:Sensitivity and Specificity
D010725:Phosphocreatine; D001224:Aspartic Acid; C000179:N-acetylaspartate; D003401:Creatine; D002794:Choline