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In this thesis, I have sought to address these issues by developing a toolbox called “Quantitative Tract Integrity Profiles (Q-TIPs)” that: is purely MATLAB-based (making it compatible with most operating systems), has a flexible and user-friendly interface, and will be distributed as a standalone toolbox for the popular Statistical Parametric Mapping (SPM) software package. This toolbox extracts the orientation of any ROI mask by calculating the medial axis using Voronoi and Delaunay algorithms, and then cross-sectional segments along the extracted medial axis are used to create profiles based on any quantitative white matter magnetic resonance imaging metric (e.g., diffusion tensor imaging, myelin water imaging, magnetization transfer imaging, etc.). As a result, this toolbox will enable future neuroimaging studies to more easily and flexibly quantify white matter imaging signals along individual tracts as a function of neural development, healthy aging, traumatic brain injury, or neurodegenerative disease. / February 2017

A research report submitted to the degree of Master of Medicine in the Department of Surgery for the University of the Witwatersrand Health Sciences, 2013 / Biliary atresia (BA) is characterised by a progressive obliterative cholangiopathy. If surgical treatment by a Kasai Portoenterostomy (KP) is undertaken early on in life there is the potential for successful bile drainage. The natural disease progression without intervention results in fibrosis and cirrhosis, necessitating liver transplantation before two years of life. Despite the advances in the management of biliary atresia over the recent decades we still do not have a good indicator of which patients will do well after surgery and which will require further intervention for their liver dysfunction. There are many clinical and serological indicators that suggest liver failure, but liver histology remains the gold standard indicating the extent of liver damage. This is, however, being slowly replaced by various new less-invasive biological markers, including the Aminotransferase Aspartate to Platelet Ratio Index (APRi). This study looks at this biological marker for patients with biliary atresia with reference to their level of disease at the time of surgery and whether it is a prognostic tool for long-term outcomes in this group of patients.

Graduation date: 1991