HIGH-RESOLUTION PROTON MR SPECTROSCOPY OF CEREBROSPINAL-FLUID IN MS PATIENTS - COMPARISON WITH BIOCHEMICAL-CHANGES IN DEMYELINATING PLAQUES

Proton magnetic resonance spectroscopy (H-1-MRS) investigation was per formed on CSF samples of patients with neurological inflammatory disea ses including 53 cases of multiple sclerosis (MS), 12 acute idiopathic polyneuropathies, 20 acute meningitides (10 viral and 10 bacterial). Spectra were compared with those acquired in 18 neurological controls. High CSF lactate levels were found in MS patients during clinical exa cerbation of relapsing-remitting course (p = 0.036 vs. neurological co ntrols). In MS patients with MRI evidence of Gd-enhanced plaques CSF l actate was higher than in patients with MRI inactive plaques (p = 0.01 7). CSF lactate positively correlated with number of CSF mononuclear c ells in MS patients with clinical activity (p = 0.05) as well as in MS patients with MRI enhancement (p = 0.003). A comparative H-1-MRS inve stigation in vivo on localized demyelinating areas confirmed an elevat ed lactate signal in Gd-enhanced (61%) more frequently than in unenhan ced (22%) plaques (p = 0.03). MS patients with high lactate signal in active plaques showed high lactate levels in CSF. Increased CSF lactat e was found also inpatients with acute meningitis and idiopathic polyn europathy. These data suggest that changes in lactate levels may depen d on anaerobic glycolytic metabolism inactivated leukocytes during inf lammatory diseases. A decrease of CSF formate levels was found in MS p atients during active and inactive clinical phase (p = 0.037, p = 0.05 vs. neurological controls respectively). Formate changes might be rel ated to a disorder of choline-glycine cycle in MS. H-1-MRS in vivo sho wed significant increase of choline in acute plaques, whereas a decrea se of N-acetyl aspartate was found in chronic plaques; these metabolit es are undetectable in CSF. CSF glucose levels were lower in bacterial than in viral meningitis (p = 0.014) and in neurological controls (p = 0.05). These observations suggest that H-1-MRS may be able to detect CSF metabolic impairment in neurological inflammatory diseases. In MS some CSF findings reflect metabolic changes occurring in brain demyel inating areas, and they could be useful for evaluation of disease acti vity in different stages of disease evolution.