Multimodality MR imaging of pathological changes in schizophrenia Aim: To prove structural changes of the neocortex and white matter of the brain indicating connectivity disorder in early phases of schizophrenia. Material and methods: A prospective monocentric study comparing a cohort of patients after the first episode of schizophrenia (on average 15.6 days after the initial hospitalization) with a control group of healthy persons. Probands were examined using a complex MRI protocol. Twenty-six patients and twenty-four healthy persons were examined in total. Three dimensional T1 and T2 data and DWI data were analyzed using TBSS FA, FBA a surface- based morphometry. Results: Large areas of dispersively decreased FA were found in patients compared to control group using TBSS. Several fixels of decreased FD metric were found using FBA in the anterior commissure of patients and one sporadic fixel of decreased FDC metric was found in frontal white matter of the brain. No statistically significant areas of cortical surface area and cortical thickness differences were found using SBM. Conclusions: Large areas of decreased microstructural integrity of the white matter of the brain were found. However, it was not possible to specify the nature of its corruption using FBA. Our findings indicate the crucial role of...

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第18174号 / 医博第3894号 / 新制||医||1003(附属図書館) / 31032 / 京都大学大学院医学研究科医学専攻 / (主査)教授 金子 武嗣, 教授 髙橋 良輔, 教授 河野 憲二 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第18854号 / 医博第3965号 / 新制||医||1007(附属図書館) / 31805 / 京都大学大学院医学研究科医学専攻 / (主査)教授 古川 壽亮, 教授 髙橋 良輔, 教授 富樫 かおり / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

Attention deficit/hyperactivity disorder (ADHD) is a common disease with a worldwide prevalence of 5% on preschool children. It has been reported that ADHD patients have volume variant in partial brain regions. Futhermore, functional magnetic resonance imaging have also been used to detect function variant possibility in particular brain regions. In the last decade, some researchers used diffusion MR imaging to investigate the abnormality of neural fibers in disease involved with central nervous system. In general, the diffusion anisotropy of white matter in both ADHD patients and healthy subjects can be estimated seperately to undergo inter-subject comparison. While previous studies often used the popular ICBM brain template (MNI152), this study applied a self-made template of Taiwan adolescents as the common space of image normailization. In this work, group comparison of diffusion fractional anisotropy was performing by using two methods, TBSS and VBM. Both manners found a decreased FA in white matter of ADHD subjects compared with normal control group. However, regions detected by different methods showed low reproducibility. The areas of significant difference include inferior longitudinal fasciculus¡Binternal capsule¡Bexternal capsule¡Bsuperior longitudinal fasciculus¡Boptic radiation¡Bsuperior frontal¡Bsuperior region of corona radiata¡Bcorticospinal tract¡Bposterior region of corona radiata / superior longitudinal fasciculus¡Bsuperior fronto-occipital fasciculus¡Banterior region of corona radiata¡Bgenu of corpus callosum nerve fibers.

Attention deficit hyperactivity disorder (ADHD) is a neurobehavior developmental disorder that affects around 7.5% of Taiwan children. With the use of magnetic resonance imaging , many results have been reported that ADHD patients have volume atrophy in gray matter and dysfunction in couples of cortical regions. In recent years, diffusion MR imaging with diffusion-sensitizing gradients has been used to investigate the abnormality of neural fibers in disease involved with central nervous system. In this study, the anisotropy of white matter in both ADHD patients and age-matched healthy subjects was estimated using diffusion tensor imaging to undergo inter-subject comparison. In this work, a significant decrease (FWE-corrected p-value <0.05) of FA values has been found in white matter of adolescents diagnosed as ADHD patients, compared with normal controls group. The areas that confirmed by two different algorithms of inter-subject comparison are mainly diffused on white matter region, including middle cerebellar peduncle, left inferior longitudinal fasciculus, internal capsule, left optic radiation, external capsule, splenium of the corpus callosum, superior longitudinal fasciculus, superior frontal and parietal-occipital nerve fibers.

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Mild cognitive impairment (MCI) is a transition phase between normal aging and Alzheimer’s disease. Individuals with MCI show impairment in cognition as well as corresponding damage to areas of their brain. Performance on tasks such as discriminating objects with ambiguous features has been associated with damage to the perirhinal cortex, while scenes with structural (spatial) elements have been associated with damage to the hippocampus. In addition, attention is regarded as one of the first non-memory domains to decline in MCI. A relatively new MRI technique called diffusion tensor imaging (DTI) is sensitive to white matter microstructural integrity and has been associated with changes due to cognitive decline. 18 MCI (14 amnesic, 4 vascular) and 12 healthy matched controls were assessed in feature ambiguity, attention and structural learning to assess associated deficits in MCI. Associations with white matter microstructural integrity were then investigated. The MCI groups were discovered to perform worse than controls on the test of structural learning. In addition, altered attention networks were found in MCI and were associated with white matter microstructural integrity. No significant differences were found for feature ambiguity. These findings suggest there may be specific damage to the hippocampus while the perirhinal cortex may be preserved in MCI. Furthermore, dysfunction in attention was found to be associated with white matter microstructural integrity. These experimental tests may be useful in assessing dysfunction in MCI and identifying degeneration in white matter microstructural integrity. Further studies with larger sample sizes are needed to validate these findings.