| Summary: | 碩士 === 國立陽明大學 === 生物醫學影像暨放射科學系暨研究所 === 97 === Schizophrenia is a mental disorder which the most common symptoms are hallucination, delusion and impairment in social cognition. Many studies have shown that schizophrenia patients might suffer from the impairments of interhemispheric information transfer. Corpus Callosum (CC) is the largest white matter (WM) structure which dominates the interhemispheric information transfer in the brain.Diffusion tensor imaging (DTI) provides a non-invasive method for visualization of WM pathways in human brain. Moreover, the DTI indices provide an quantitative method to examine the WM tracts integrity and subtle pathological changes.
DTI and structural MRI scans were obtained from 50 schizophrenia and 50 control subjects. Probabilistic tracking algorithm was used to obtain the CC topography since each portion of CC fibers connect to different brain cortices . Mean fractional anisotropy (FA),first eigen value (FEV), and radial diffusivity (RD) were compared on each callosal subdivision between the two groups. The relationships
between DTI indices and clinical variables, such as duration of illness, were investigated as well.
Compared with controls, decreased FA was found in the subdivions connecting to the prefrontal, premotor, posterior parietal, and occipital cortices in subjects with schizophrenia. Specifically, FA showed a non-linear correlation with the duration of illness in the subdivision connecting to the prefrontal cortex. In addition, the gender effect revealed different patterns in two groups.
This study provides a quantitative evidence for the reduction of inter-hemispheric brain connectivity in schizophrenia; meanwhile, the effects of duration of illness and gender were discussed. The finding may support the hypo-connectivity model of schizophrenia.
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