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Clinical application of functional magnetic resonance imaging

Thesis/Dissertation:

Abstract

The work described in this thesis was carried out at the Magnetic Resonance Centre of the University of Nottingham during the time from May 1998 to April 2001, and is the work of the author except where indicated by reference. The main source of signal changes in functional magnetic resonance imaging (fMRJ) is the fluctuation of paramagnetic deoxyhaemoglobin in the venous blood during different states of functional performance. For the work of this thesis, fMRI studies were carried out using a 3 T MR system with an echo planar imaging (EPI) pulse sequence. Hearing research utilising fMRI has been previously reported in normal subjects. Hearing fMRI is normally performed by stimulating the auditory cortex via an acoustic task presentation such as music, tone, etc. However, performing the same research on deaf subjects requires special equipment to be designed to allow direct stimulation of the auditory nerve. In this thesis, a new method of direct electrical stimulation of the auditory nerve is described that uses a transtympanic electrode implanted onto the surface of the cochlea. This approach would however, result in electromotive forces (EMFs) being induced by the time varying magnetic field, which would lead to current flow and heating, as  More>>
Publication Date:
Jul 01, 2002
Product Type:
Thesis/Dissertation
Resource Relation:
Other Information: TH: Thesis (Ph.D.); Country of input: International Atomic Energy Agency (IAEA); PBD: 2002
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; DIAGNOSTIC USES; ELECTROMOTIVE FORCE; IMAGE PROCESSING; IMAGES; MAGNETIC FIELDS; NUCLEAR MAGNETIC RESONANCE
OSTI ID:
20329639
Research Organizations:
University of Nottingham (United Kingdom)
Country of Origin:
United Kingdom
Language:
English
Other Identifying Numbers:
TRN: GB0303432018762
Availability:
Available from British Library Document Supply Centre- DSC:DXN054720
Submitting Site:
GBN
Size:
vp.
Announcement Date:

Thesis/Dissertation:

Citation Formats

Alwatban, Adnan Z W. Clinical application of functional magnetic resonance imaging. United Kingdom: N. p., 2002. Web.
Alwatban, Adnan Z W. Clinical application of functional magnetic resonance imaging. United Kingdom.
Alwatban, Adnan Z W. 2002. "Clinical application of functional magnetic resonance imaging." United Kingdom.
@misc{etde_20329639,
title = {Clinical application of functional magnetic resonance imaging}
author = {Alwatban, Adnan Z W}
abstractNote = {The work described in this thesis was carried out at the Magnetic Resonance Centre of the University of Nottingham during the time from May 1998 to April 2001, and is the work of the author except where indicated by reference. The main source of signal changes in functional magnetic resonance imaging (fMRJ) is the fluctuation of paramagnetic deoxyhaemoglobin in the venous blood during different states of functional performance. For the work of this thesis, fMRI studies were carried out using a 3 T MR system with an echo planar imaging (EPI) pulse sequence. Hearing research utilising fMRI has been previously reported in normal subjects. Hearing fMRI is normally performed by stimulating the auditory cortex via an acoustic task presentation such as music, tone, etc. However, performing the same research on deaf subjects requires special equipment to be designed to allow direct stimulation of the auditory nerve. In this thesis, a new method of direct electrical stimulation of the auditory nerve is described that uses a transtympanic electrode implanted onto the surface of the cochlea. This approach would however, result in electromotive forces (EMFs) being induced by the time varying magnetic field, which would lead to current flow and heating, as well as deflection of the metallic electrode within the static magnetic field, and image distortion due to the magnetic susceptibility difference. A gold-plated tungsten electrode with a zero magnetic susceptibility was developed to avoid image distortion. Used with carbon leads and a carbon reference pad, it enabled safe, distortion-free fMRI studies of deaf subjects. The study revealed activation of the primary auditory cortex. This fMRI procedure can be used to demonstrate whether the auditory pathway is fully intact, and may provide a useful method for pre-operative assessment of candidates for cochlear implantation. Glucose is the energy source on which the function of the human brain is entirely dependent. Failure to maintain blood sugar levels may cause significant impairment of brain cognition. Investigation of the anatomical basis of these areas requires an attention demanding task and rapid responses. In this study, a paradigm involving a visual information processing task was described. The task was used to assess the possible modulatory effects of nutritional states and controlled hypoglycaemia on brain cognition. The behavioural data revealed that individuals perform the task differently and the ability of each individual on performing the task does not change over several tasks. However, fMRI data revealed different results on repeating the experiment possibly due to the involvement of the learning processes. The study may be a good method to study for the effects of food products and controlled hypoglycaemia on cognitive performance, if the learning effects are controlled for. (author)}
place = {United Kingdom}
year = {2002}
month = {Jul}
}