Metabolic Abnormalities in Pain-Processing Regions of Patients with Fibromyalgia: A 3T MR Spectroscopy Study

BACKGROUND AND PURPOSE: A growing body of evidence suggests the involvement of the brain in FM. The purpose of this proton MRS study was to test the hypothesis that there are metabolic alterations in some brain regions processing pain (VLPFC and thalamus) in patients with FM compared with HC. MATERIALS AND METHODS: Twelve patients with FM (30-54 years of age; mean age, 43.2 years), and 12 HC, matched for age and sex, underwent 1 session of single-voxel MRS performed on a 3T MR imaging scanner. MRS spectra were acquired with a PRESS for localization. The raw data from each spectrum was evaluated with an LCModel. T tests were used to evaluate differences of brain metabolites between groups. The Pearson correlation tested the relationship of metabolite ratios and clinical symptoms. RESULTS: Glx/Cr and Glu/Cr ratios within the VLPFC of both sides were significantly higher in patients than in HC (P < .01). No significant differences of metabolites between groups were found in the thalami. Positive correlations were found between Glu/Cr in the left thalamus and the VAS for pain (r =0.730, P = .007) and between mIns/Cr in the right VLPFC and the VAS for pain (r = 0.607, P = .037) and the FIQ (r = 0.719, P = .008). CONCLUSIONS: The presence of elevated Glu/Cr levels in VLPFC strengthens the opinion that a complex neurophysiologic imbalance of different brain areas involved in pain processing underlies FM. These data may be useful in the diagnosis and development of more effective pharmacologic treatments.