Quantative analysis of brain white matter using diffusion tensor imaging
| dc.contributor.author | Mohd Taib, Nur Hartini | |
| dc.date.accessioned | 2017-09-11T08:02:37Z | |
| dc.date.available | 2017-09-11T08:02:37Z | |
| dc.date.issued | 2014-12 | |
| dc.description.abstract | This research is concerned with the application of diffusion tensor imaging (DTI) in the study of leukoaraiosis and normal white matter. Four main objectives outlined in the study have been achieved. A head phantom was used and a total of 15 normal subjects and 51 leukoaraiosis subjects participated in the study. A total of 5128 slices were analysed in this work. Brain imaging was performed using 1.5 Tesla MRI system. Feasibility of acquiring DTI data and constructing fiber tracts for leukoaraiosis study was investigated. Results obtained showed capability of DTI to distinguish leukoaraiosis from normal white matter. Fiber tractography exhibited a good structural differentiation of nerve fibers in the white matter region. Acquiring DTI data and constructing fiber tractography for assessment of leukoaraiosis was found to be feasible. Optimum combination of voxel size resolution and b-value for the whole brain imaging has also been determined. Six protocols which consist of the combination of various voxel size and b-value were evaluated. Measurement of signal-to-noise ratio (SNR) and DTI parameter indices was carried out for both phantom and in-vivo studies. It was found that protocols with voxel 2.5 × 2.5 × 2.5 mm3 give the desired SNR of at least 20. The optimal combination of parameters are the voxel size of 2.5 × 2.5 × 2.5 mm3 with b-value of 700 s/mm2. Assessment of leukoaraosis (LA) at different region in the brain using mean diffusivity (MD) and fractional anisotropy (FA) values were carried out. The MD and FA values were compared with that of measured at normal appearing brain tissue (NABT) from leukoaraiosis subjects and normal brain tissue (CONTROL) from healthy subjects. It was found that LA demonstrated a significantly higher MD and lower FA as compared to NABT in frontal and occipital white matter areas. No differences were noted in MD and FA with regard to all white and grey matter regions between NABT and CONTROL categories. From fibre tractography it was also found that there is major reduction in the number of neural fibres in leukoaraiosis subject as compared to normal subject. Characterization of leukoaraiosis was performed using lesion-to-normal appearing white matter ratio (LNR). This method is proposed for the first time. Another new approach is measurement of lesion volume at each specific lesion spot. Correlation between LNR and lesion volume indicated that LNR is not associated with the lesion volume. Therefore, it is suggested that the degree of tissue destruction is not associated with size of the lesion. | en_US |
| dc.identifier.uri | http://hdl.handle.net/123456789/4586 | |
| dc.language.iso | en | en_US |
| dc.publisher | Universiti Sains Malaysia | en_US |
| dc.subject | Diffusion tensor imaging (DTI) | en_US |
| dc.title | Quantative analysis of brain white matter using diffusion tensor imaging | en_US |
| dc.type | Thesis | en_US |
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