Abnormal white matter microstructure in Parkinson's disease revealed by diffusion tensor imaging A non-randomized concurrent control observation

BACKGROUND: Imaging has been used to determine gray matter volume and metabolism in subjects with depressed Parkinson's disease (DPD). OBJECTIVE: To reveal abnormalities in orbitofrontal white matter and the anterior cingulate bundle in depressed and non-depressed Parkinson's disease (NDPD) patients using diffusion tensor imaging. DESIGN, TIME AND SETTING: A non-randomized, concurrent, control, neuroimaging study was performed at the Laboratory of Neurodegenerative Diseases and Center of Neuroimage, Xuanwu Hospital of Capital Medical University from July 2008 to January 2009. PARTICIPANTS: A total of 30 Parkinson's disease patients, including 14 males and 16 females, were included in the present study. All patients met Brain Bank criteria for idiopathic Parkinson's disease formulated by the United Kingdom Parkinson's Disease Society. Patients, who underwent previous head surgery, exhibited abnormal density on T2-weighted images, or Mini-Mental State Examination scores < corresponding education level, were excluded from the study. METHODS: All 35 patients underwent MRI scans, including traditional T2-weighted and DTI scans. The patients were assigned to DPD (n = 16) and NDPD (n = 14) groups according to the Diagnostic and Statistical Manual of Mental Disorders-IV (DSM-IV) criteria. The fractional anisotropy values of regions of interest were compared between the NDPD and DPD groups. MAIN OUTCOME MEASURES: Abnormalities in the orbitofrontal white matter and anterior cingulate bundle. RESULTS: Compared with the NDPD group, the DPD group exhibited significantly lower fractional anisotropy values in orbitofrontal white matter and anterior cingulate bundle (P < 0.05). CONCLUSION: Microstructure abnormalities existed in the orbitofrontal and anterior cingulate regions in DPD patients. This is the first report of abnormalities in the orbitofrontal white matter region in DPD patients.