Magnetic Resonance Spectroscopy (MRS) can be applied to probe noninvasively the concentrations and distribution of metabolites of human tissue in vivo. As the improving of hardware and localization techniques, MRS becomes more and more important in clinical applications. Furthermore, some post-processing software, like LCModel, provide a graphical user interface for efficient and convenient analysis of MR spectroscopic imaging and thus increase the value of MRS applications. Although LCModel provides an efficient analysis and produces stable results, it can not provide metabolite map to observe the distribution of metabolite concentrations. For this reason our study processes the output data of LCModel and Digital Imaging and Communications in Medicine (DICOM) format MR images for 2D/3D metabolite map displaying. Users can use this software to observe the metabolic distribution in AP, SI and RL slice of brain tissue. In the meanwhile, as the absolute quantification of MRS has played more and more important role in clinical applications, this study also provides the LCModel end users an easy way for interpretation.

Magnetic resonance spectroscopy is now in widespread use, which with various tools of spectra analysis can provide concentrations of metabolites. The influence of metabolites on human physiology is greatly. Due to the tiny variation of the concentration in various metabolites, the analytic method used in the quantitative determination of the absolute concentrations of metabolites plays an important role in this research area. In this thesis we present an analysis tool for segmentation of white matter, gray matte and cerebrospinal fluid using region growing with spatial space, and provide manual interaction for exception handling in this subject. Then we use this tool to analyze different percentages of white matter and gray matter with the default parameter by LCModel and correct partial volume effect. The results show that the proposed tool can improve significantly the accuracy in absolute quantitative analysis of concentration.

Thesis (Ph. D.)--University of Washington, 2000. / Vita. Includes bibliographical references (leaves 217-229).

Thesis (Ph. D.)--University of Hong Kong, 2010. / Includes bibliographical references (leaves 338-340). Also available in print.

Thesis (Ph. D.)--University of Hong Kong, 2010. / Includes bibliographical references (leaves 338-340). Also available online.

Thesis (Ph. D.)--University of Texas at Austin, 2000. / Vita. Includes bibliographical references (leaves 126-139). Available also in a digital version from Dissertation Abstracts.

Thesis (Ph. D.)--School of Textile and Fiber Engineering, Georgia Institute of Technology, 2004. Directed Haskell W. Beckham. / Includes bibliographical references.

Thesis (Ph. D.)--University of Hong Kong, 1989.

Thesis (Ph. D.)--University of Hong Kong, 1988.

Magnetic Resonance Spectroscopy (MRS) was used to study the relationship between brain regional concentrations of metabolites and normal aging in Chinese. Our goal in this study is to create a database of normal aging and hence enhance further understanding on the degenerative process leading to dementia and related neurodegenerative diseases. Thirty cognitively normal healthy volunteers of age 22-82 years were recruited and the bias on gender effect in data sampling was minimized by recruiting 15 females and 15 males. In the first part of the study, 1H MRS was obtained using single-voxel-spectroscopy (SVS). Offline software java-based version of Magnetic Resonance User Interface (jMRUI) was employed for data analysis. Cerebrospinal fluid was normalized using software voxel based morphormetry (VBM). Brain morphometry data was also analyzed. Brain metabolites choline (Cho), creatine (Cr) and N-acetyl aspartate (NAA) were quantified using internal water as reference. It was found that brain metabolite concentrations of Cr, Cho and NAA increase significantly with age. Gender effect on metabolite concentrations were also discovered, being higher in the female group. For brain morphometry, white matter and grey matter volumes and fractions all reveal a siginificant negative correlation with age, whereas CSF volume and fraction show a significant positive correlation with age. Gender effect was found on grey matter, white matter and intracranial volume, being higher in the male group. In the second part of the study, 31P SVS MRS was performed on the same population of volunteers. jMRUI was also employed for data analysis. Metabolic ratios were obtained. Similar to the 1H MRS study, apart from creating a database in studying normal aging, an additional aim of this 31P MRS study is to correlate with 1H MRS and assist in interpreting the corresponding metabolic activity. Brain metabolite concentrations were found to increase significantly with age. The increase of PCr (phosphocreatine)/Ptot (total phosphorus content) in posterior cingulate suggests lower metabolic activity throughout the course of aging. The strong evidence of PDE (phosphodiester) increase with age in left hippocampus proposes the fact that phospholipid membrane breakdown will be enhanced by aging. In conclusion, MRS can act as a non-invasive tool to study aging at molecular level. Metabolite levels are significant means to investigate the metabolic change in the human brain during the process of aging as the variations in metabolite levels are believed to be footprints of biochemical changes. / published_or_final_version / Diagnostic Radiology / Master / Master of Philosophy