eprintid: 1426205
rev_number: 65
eprint_status: archive
userid: 608
dir: disk0/01/42/62/05
datestamp: 2014-10-10 07:30:10
lastmod: 2022-01-12 00:01:54
status_changed: 2014-10-10 07:30:10
type: thesis
metadata_visibility: show
item_issues_count: 0
creators_name: Richardson, S
title: A Viable Isolated Tissue System: A Tool for Detailed MR Measurements and Controlled Perturbations in Physiologically Stable Tissue
ispublished: unpub
divisions: UCL
divisions: B02
divisions: C07
divisions: D07
divisions: F83
divisions: C10
divisions: D17
divisions: G94
divisions: B04
divisions: C05
divisions: F48
keywords: MRI, Diffusion MRI, Viable Isolated Tissue, Additive Layer Manufacturing, Chemical Fixation, Functional Diffusion MRI, Modelling
abstract: The research presented in this thesis revolves around developing, testing and applications of a tool for the development and assessment of diffusion weighted MRI and methods. The tool is a viable isolated tissue (VIT) maintenance chamber. The chamber was designed to maintain a section of rat optic nerve white matter in a stable state, as close to in vivo conditions as possible, while removing all of the confounding problems of imaging such tissue in a live animal. The chamber was designed to fit into a small volume coil in a high field horizontal bore MRI scanner and to enable extended periods of in depth, detailed experimentation. Additive layer manufacturing was used to construct the chamber. A series of validation experiments were conducted to demonstrate the performance of the chamber and the stability of optic nerves maintained within it. Fixed samples have been used extensively in diffusion MRI (dMRI) studies. However, fixation causes significant structural changes in tissue. The chamber was used to evaluate fixed white matter as a surrogate for viable white matter during development and validation of dMRI methods. Diffusion tensors and multi-compartment white matter signal models were fit to the data. The data demonstrated that fixed tissue, while maintaining the broad water environment of viable tissue, differs significantly in diffusion parameters. The chamber was further developed to enable in MRI electrophysiological stimulation and recording from the rat optic nerve. This EP-MRI chamber was designed to enable investigation of the existence of a dMRI measurable structural change in the tissue upon electrical activation. The functional diffusion MRI (dfMRI) signal could be more specific to in vivo functional activation that the gold-standard fMRI method which measures blood oxygenation levels to produce contrast. Preliminary data suggests that a purely structural dfMRI effect, though marginal, may be present in this simplified system.
date: 2014-05-28
vfaculties: VGHCSCI
vfaculties: VENG
vfaculties: VENG
oa_status: green
full_text_type: other
thesis_class: doctoral_open
language: eng
thesis_view: UCL_Thesis
dart: DART-Europe
primo: open
primo_central: open_green
verified: verified_manual
elements_source: Manually entered
elements_id: 940359
language_elements: EN
lyricists_name: Alexander, Daniel
lyricists_name: Lythgoe, Mark
lyricists_name: Richardson, Simon
lyricists_name: Siow, Bernard
lyricists_id: DALEX06
lyricists_id: MFLYT72
lyricists_id: SRICH17
lyricists_id: BSIOW77
full_text_status: public
pagerange: 1 - 162
pages: 162
institution: UCL (University College London)
department: Medical Physics and Bioengineering
thesis_type: Doctoral
editors_name: Alexander, DC
editors_name: Lythgoe, 
editors_name: Siow, 
citation:        Richardson, S;      (2014)    A Viable Isolated Tissue System: A Tool for Detailed MR Measurements and Controlled Perturbations in Physiologically Stable Tissue.                   Doctoral thesis , UCL (University College London).     Green open access   
 
document_url: https://discovery.ucl.ac.uk/id/eprint/1426205/1/Richardson_Simon__Thesis_Final_SR.pdf