title: Manual and semi-automatic quantification of in vivo ¹H-MRS data for the classification of human primary brain tumors.
abstract: In vivo proton magnetic resonance spectroscopy (¹H-MRS) is a technique capable of assessing biochemical content and pathways in normal and pathological tissue. In the brain, ¹H-MRS complements the information given by magnetic resonance images. The main goal of the present study was to assess the accuracy of ¹H-MRS for the classification of brain tumors in a pilot study comparing results obtained by manual and semi-automatic quantification of metabolites. In vivo single-voxel ¹H-MRS was performed in 24 control subjects and 26 patients with brain neoplasms that included meningiomas, high-grade neuroglial tumors and pilocytic astrocytomas. Seven metabolite groups (lactate, lipids, N-acetyl-aspartate, glutamate and glutamine group, total creatine, total choline, myo-inositol) were evaluated in all spectra by two methods: a manual one consisting of integration of manually defined peak areas, and the advanced method for accurate, robust and efficient spectral fitting (AMARES), a semi-automatic quantification method implemented in the jMRUI software. Statistical methods included discriminant analysis and the leave-one-out cross-validation method. Both manual and semi-automatic analyses detected differences in metabolite content between tumor groups and controls (P < 0.005). The classification accuracy obtained with the manual method was 75% for high-grade neuroglial tumors, 55% for meningiomas and 56% for pilocytic astrocytomas, while for the semi-automatic method it was 78, 70, and 98%, respectively. Both methods classified all control subjects correctly. The study demonstrated that ¹H-MRS accurately differentiated normal from tumoral brain tissue and confirmed the superiority of the semi-automatic quantification method.
authors.affiliation: Departamento de Raios Cósmicos e Cronologia, Instituto de Física Gleb Wataghin, Faculdade de Ciências Médicas, Universidade de Campinas, SP, Brasil.
authors.forename: S
authors.initials: S
authors.lastname: Cuellar-Baena
authors.forename: L M T S
authors.initials: LM
authors.lastname: Morais
authors.forename: F
authors.initials: F
authors.lastname: Cendes
authors.forename: A V
authors.initials: AV
authors.lastname: Faria
authors.forename: G
authors.initials: G
authors.lastname: Castellano
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000145:classification* / Q000378:metabolism / Q000473:pathology; D016022:Case-Control Studies; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008875:Middle Aged; D009367:Neoplasm Staging; D010865:Pilot Projects; D012680:Sensitivity and Specificity; D055815:Young Adult