Purpose: Localized 1H-MRS was used to measure 22 previously untreated depressive patients before and after treatment with Citalopram. Absolute values (mmol/kg wet weight) of the measured metabolites were obtained using LCModel. Compared to controls, depressive patients showed significantly higher absolute concentrations of tCr left-frontally and right-frontally. Four weeks after treatment patients were studied again and metabolic changes for the whole group and subgroups were calculated. tCr was lower after 4 weeks of treatment (not significant) for the whole group. The group responding to the clinical treatment showed reduced tCr right (p=0.058) and left-frontally (n.s.). To our best knowledge, this is the first proton MRS study, monitoring the effect of drug treatment on depressive patients.
Methods and Materials: 22 depressive patients were scanned before and after treatment with Citalopram and compared with 22 age- and sex-matched healthy subjects (36 +/- 12 years) in a double blinded parallel group design on a 3T whole body system (Bruker Medspec S300, Germany) using a standard birdcage coil. Absolute concentrations of tCr, NAA, tCho and mI, taking the unsuppressed water signal of the same voxel as a reference, were calculated using LCModel (Version 5.2-2). Group statistics were performed using a t-test for paired samples.
Results: In patients and in controls, all spectra showed a signal/noise ratio >= 4 and a linewidth FWHM <= 0.075 ppm. Compared to controls, depressive patients showed significantely higher absolute concentrations of tCr left-frontally (14%, p=0.02 ) and right-frontally (19%, p=0.008). Four weeks after treatment tCr in patients was lower compared to baseline with a trend left-frontally ( 8%, p=0.08.) and right-frontally (12%, n.s.). However, there were no significant differences between the post-treatment findings and the control group. In the group responding to antidepressive medication tCr tended to decrease in the left fontal lobe (13%, p=0.058).
Conclusion: 1H-MRS may be useful to explore the underlying metabolic mechanism in depressive patients. Additionally, the effects of treatment can be studied, with sufficient sensitivity at 3 Tesla.