A Proton Magnetic Resonance Spectroscopy Imaging Study On Prefrontal Lobe And Hippocampus In Patients With Obsessive-compulsive Disorder

BackgroundObsessive-compulsive disorder (OCD) is a prevalent, serious psychiatric disorder of unknown etiology. Several lines of investigation into the causes of OCD have suggested that it is characterized by dysfunction within a certain brain region. More recently, researchers have begun using magnetic resonance spectroscopy (MRS) to evaluate potential differences in regional brain metabolites between patients with OCD and healthy controls. They have revealed activation within the prefrontal region along with other brain regions such as medial orbitofrontal cortex, anterior cingulated and amygdala. But no studies have found identical results. MRS is a technique that allows the non-invasive measurement of brain metabolites. In the present study, we applied MRS to examine levels of neurochemicals in the prefrontal lobe and hippocampus in patients with OCD versus healthy controls. MRS studies inOCD have the potential effect to increase our understanding of the connection between the observable symptoms and associated neurobiology, and perhaps lead to improvements in diagnosis and treatment.Subjects and methodsA 1.5-T nuclear magnetic resonance machine was used to test 10 patients (18-60years;mean age±SD, 32.4±12.6years) and 10 healthy volunteers matched for age, sex, and handedness (18-60years;mean age±SD, 30.3±6.5years).~1H-MRS was carried out using PRESS for spatial localization (repetition time = 1500 msec, echo time =135 msec, repetition time = 1500 msec, average number = 192, acquire time =4min48sec). The T2-weighted series was used to prescribe an 15×15×15mm~3 volume of interest in the prefrontal lobe and the hippocampus. CHESS was used to provide maximum water suppression. The NAA, Cho and Cr were measured and the ratios of NAA/Cr and Cho/Cr were determined. Spectral data were analyzed using SPSS11.0 software.ResultsThe NAA/Cr ratios in bilateral prefrontal lobe in patients with OCD were higher than those in healthy controls (P <0.05) ; The NAA in the right prefrontal lobe in patients with OCD were higher than those in healthy controls (P <0.05) ; The NAA/Cr ratios in the left hippocampus in patients were higher than those in healthy controls (P<0.05). The Cho/Cr ratios in bilateral hippocampus and the Cho in right hippocampus in patients were higher than those in healthy controls (P<0.05).ConclusionsOur results confirm that there might exist both abnormal metabolize of membrane in hippocampus and increased neuronal vitality in bilateral prefrontal lobeand left hippocampus in the patients with obsessive-compulsive disorder. These results provide new evidence of localized functional neurochemical marker alterations in the patients with OCD.