A MULTIPARAMETRIC DATA-ANALYSIS SHOWING THE POTENTIAL OF LOCALIZED PROTON MR SPECTROSCOPY OF THE BRAIN IN THE METABOLIC CHARACTERIZATION OFNEUROLOGICAL DISEASES
S. Confortgouny et al., A MULTIPARAMETRIC DATA-ANALYSIS SHOWING THE POTENTIAL OF LOCALIZED PROTON MR SPECTROSCOPY OF THE BRAIN IN THE METABOLIC CHARACTERIZATION OFNEUROLOGICAL DISEASES, Journal of the neurological sciences, 118(2), 1993, pp. 123-133
We conducted an extended clinical evaluation of localized proton magne
tic resonance spectroscopy (MRS) of the brain, performed on various br
ain diseases using short stimulated echo times. Pathologies studied we
re mainly multiple sclerosis, stroke, leukoaraiosis, AIDS-related leuk
oencephalopathies and glial tumors. Other miscellaneous pathologies we
re also studied. Magnetic resonance examination of the brain was condu
cted on a Siemens Magnetom SP63 (equipped with a 1.5 T magnet). Locali
zed proton MRS was performed on a routine basis immediately after imag
ing, using the STEAM (stimulated echo acquisition mode) with a short e
cho time (20 ms) combined with a CHESS (chemical shift selective excit
ation) sequence. One or two VOI (8 ml) were examined. Data on 125 spec
tra were processed by principal component analysis (PCA) and conventio
nal variance analysis. The following metabolite resonances were studie
d: inositol-glycine, taurine-scyllo-inositol, choline derivatives, pho
sphocreatine-creatine, aspartate, glutamine glutamate, N-acetylasparta
te, acetate and lactate. PCA demonstrates that the different metabolic
variables are independent. The analysis of groups of spectra clearly
demonstrates that the metabolic profiles detected by localized MRS in
various pathologies (i) differ significantly from controls, and (ii) a
llow a metabolic discrimination between groups of pathologies. Results
of PCA are confirmed by variance analysis. Strokes are characterized
by an increase in lactate concentration and leukoaraiosis by a decreas
e in inositol-glycine resonance. AIDS-related leukodystrophies are cha
racterized by increases in lactate and choline concentrations. Reducti
on in N-acetylaspartate which is observed in most pathologies is not s
ignificant in the small lesions of white matter. Lactate has often bee
n found in MS plaques, but no variation in the choline/phosphocreatine
ratio was observed. GABA was tentatively assigned in the spectrum of
a patient with epilepsy under sodium valproate treatment. This study i
llustrates the clinical feasibility of the technique, the value of a m
ultiparametric data analysis in the definition of the pertinent variab
les characterizing the metabolic impairment, and the impact of localiz
ed proton MR spectroscopy of the brain in the assessment of cerebral s
uffering.