Localized 1H-NMR spectroscopy in patients with fibromyalgia: a controlled study of changes in cerebral glutamate/glutamine, inositol, choline, and N-acetylaspartate.
BACKGROUND
The purpose of this study was to investigate whether single-voxel (SV) proton magnetic resonance spectroscopy (MRS), diffusion-weighted imaging (DWI), and diffusion tensor imaging (DTI) detected differences between fibromyalgia (FM) patients and healthy controls. We also searched for correlations between neuroimaging abnormalities and neuropsychological variables.


METHODS
Ten patients with FM and 10 gender- and age-matched control subjects were studied. A neuropsychological examination, DWI, DTI, and proton MRS were performed on the brain areas known to be associated with pain processing.


RESULTS
Compared with healthy controls, FM patients had significantly higher levels of glutamate + glutamine (Glx) (mean ± SD, 10.71 ± 0.50 arbitrary institutional units versus 9.89 ± 1.04; P = 0.049) and higher glutamate + glutamine/creatine (Glx/Cr) ratios (1.90 ± 0.12 versus 1.72 ± 0.23; P = 0.034) in the posterior gyrus. Myoinositol (Ins) levels of the right and left hippocampi were significantly lower in FM patients (4.49 ± 0.74 versus 5.17 ± 0.62; P = 0.008 and 4.91 ± 0.85 versus 6.09 ± 0.78; P = 0.004, respectively). In FM patients, decreased myoinositol/creatine (Ins/Cr) ratios were found in the left sensorimotor area (P = 0.05) and the left hippocampus (P = 0.002) and lower levels of choline (P = 0.019) and N-acetyl aspartate + N-acetyl aspartyl glutamate (NAA + NAG) (P = 0.034) in the left hippocampus. Significant correlations between depression, pain, and global function and the posterior gyrus Glx levels and Glx/Cr ratios were observed.


CONCLUSIONS
Glx within the posterior gyrus could be a pathologic factor in FM. Hippocampal dysfunction may be partially responsible for the depressive symptoms of FM. Additional studies with larger samples are required to confirm these preliminary data.
Fayed
Nicolas
N
Department of Radiology, Hospital Quirón, Paseo de Mariano Renovales, Zaragoza, Spain. nicola33fr@yahoo.es
Garcia-Campayo
Javier
J
Magallón
Rosa
R
Andrés-Bergareche
Helena
H
Luciano
Juan V
JV
Andres
Eva
E
Beltrán
Julián
J
D000328:Adult; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D001921:Brain / Q000378:metabolism* / Q000473:pathology*; D019826:Cholic Acid / Q000378:metabolism; D003430:Cross-Sectional Studies; D056324:Diffusion Tensor Imaging; D005260:Female; D005356:Fibromyalgia / Q000378:metabolism / Q000473:pathology; D018698:Glutamic Acid / Q000378:metabolism; D005973:Glutamine / Q000378:metabolism; D006624:Hippocampus / Q000378:metabolism* / Q000473:pathology*; D006801:Humans; D007294:Inositol / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000378:metabolism / Q000473:pathology; D019906:Nuclear Magnetic Resonance, Biomolecular; D010146:Pain / Q000378:metabolism / Q000473:pathology; D011522:Protons; D013003:Somatosensory Cortex / Q000378:metabolism / Q000473:pathology
D011522:Protons; D005973:Glutamine; D001224:Aspartic Acid; D018698:Glutamic Acid; D007294:Inositol; C000179:N-acetylaspartate; D019826:Cholic Acid