Abstract:

Objective To quantitatively measure the concentrations of metabolites in both frontal and temporal lobes after sodium valproate medication in bipolar patients to determine if these were altered in any way from controls.Methods We studied 9 adult patients with bipolar disorder and 11 healthy volunteers as controls.All the patients took sodium valproate 1 000 mg daily as the sole medication.MR was performed by using a Magnex 3 T scanner and a 1.5T MR scanner.The PRESS sequence was used to acquire proton MRS data with TE1=25 msec,TE2=25 msec,TR=3 000 msec,and 128 scan averages.The MRS data were acquired from three square voxels(2×2×2 cm³) placed in the cortex of frontal lobe,the cortex of temporal lobe,and external standard solution.By measuring T1 and T2 values of the metabolites in the brain and standard solution,accurate brain metabolite concentrations were obtained.Results Similar spectra were found among healthy volunteers and the patients with bipolar disorder.Compared with the concentration of myo-inositol in volunteers,the patients had no significantly lower levels of myo-inositol(P=0.79 in frontal lobe and P=0.94 in temporal lobe,onewey ANOVA).Also,there were no significant differences for choline,total creatine and NAA between volunteer and patient groups.Conclusion Sodium valproate administration does not significantly alter baseline concentrations of myo-inositol in euthymic bipolar patients.It is also possible that there is a limitation for in vivo MRS PRESS sequence to detect the changes in myo-inositol concentration even if there is any change.

Key words: magnetic resonance spectroscopy, brain myo-inositol, sodium valproate