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Williams, Hannah (2020) Quantitative measures for gastrointestinal MRI. PhD thesis, University of Nottingham.

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Abstract

The use of Magnetic Resonance Imaging (MRI) as both a clinical and research tool has increased substantially over the last 40 years. However, one area of use that has seen a smaller benefit from this increase is the structure and function of the gastrointestinal system. Faster acquisition methods and improved computer analysis techniques now mean that measures that are routinely made outside of the abdomen can start to be utilised in the gastrointestinal system.

The aim of this thesis was to address key gaps in the availability of quantitative measures in the gastrointestinal system using MRI. Whilst there are many challenges that could have been addressed, three areas which all relate to inflammatory gastrointestinal diseases were chosen.

The first relates to the lymphatic system which plays an essential role in all inflammatory diseases. Quantitative measures of the lymphatic system in the abdomen could provide further insight into GI diseases. In this thesis methods to visualise the abdominal lymph nodes were developed and significant differences between the lymph nodes in patients with inflammatory gastrointestinal disease and healthy volunteers were measured.

The second area of focus was the bowel wall which is implicated in many inflammatory gastrointestinal diseases. Its relatively small size and unpredictable motion have meant that common MRI measures such as T1 and T2 have never been made in the non-enlarged bowel wall. In this thesis T2 was shown to correlate with the current standard measures of bowel wall permeability providing a new non-invasive method of investigating the structure of the bowel wall.

The third and final area was the quantification of fat in the abdomen. Whilst this topic has largely been tackled in the liver at low field strengths the confounding factors that effect its measurement have not been taken into account outside the liver or at higher field strengths. The current methods of fat quantification were tested and found to not be appropriate for use in the colon at 3T due to the large field inhomogeneities present. The first in vivo fat quantification maps at 7T were generated using in-house fitting methods which was found to perform better than the current vendor product for fat quantification.

Bringing these three topics together provides a good starting block for tackling the deficiencies currently present in quantitative GI MRI and the tools developed throughout this thesis will be applicable across many diseases that impact the gastrointestinal system.

Item Type:	Thesis (University of Nottingham only) (PhD)
Supervisors:	Gowland, Penny Marciani, Luca
Subjects:	Q Science > QC Physics
Faculties/Schools:	UK Campuses > Faculty of Science > School of Physics and Astronomy
Item ID:	59992
Depositing User:	Williams, Hannah
Date Deposited:	15 Jul 2020 04:40
Last Modified:	31 Jan 2023 09:02
URI:	https://eprints.nottingham.ac.uk/id/eprint/59992

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