Advances in MRI to probe the functional and structural network of the macaque brain

Diffusion MRI and fMRI have provided neuroscientists with non-invasive tools to probe the functional and structural network of the brain. Diffusion MRI is a neuroimaging technique capable of measuring the diffusion of water in neural tissue. It can reveal histological architecture irresolvable by conventional magnetic resonance imaging methods and has emerged as a powerful tool to investigate a wide range of neuropathologies. fMRI is a neuroimaging technique sensitive to hemodynamics which is indirectly linked to neural activity. Despite the applications of diffusion MRI and fMRI in basic and clinical neuroscience, the underlying biophysical mechanisms of cerebral diffusion and the hemodynamic response remain largely unknown. Also, these neurotechnqiues suffer from low SNR compared to conventional MRI. The challenges associated with the acquisition and interpretation of diffusion MRI and fMRI limit the application of these powerful non-invasive neuroimaging tools to study the functional and structural network of the brain. The purpose of this thesis is three fold; (1) improve the acquisition and reconstruction of the diffusion MRI and fMRI signals and (2) develop an MR-compatible cortical cooling system to reversibly deactivate cerebral glucose metabolism, and (3) apply the cortical cooling system to investigate the effect of cerebral glucose metabolism on cerebral diffusion and the hemodynamic response. First, I describe a novel phased array monkey coil capable of improving the resolution of diffusion MRI (4 fold increase) and fMRI (2 fold increase) in monkeys. Secondly, I present a novel reconstruction method to resolve complex white matter architecture which boosts the sampling efficiency of the diffusion MRI acquisition by 274-377%.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Nuclear Science and Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2007

Author dc:creator

• Khachaturian, Mark Haig, 1979-

Advisor dc:contributor.advisor

• Wim Vanduffel and David Tuch.

• Nuclear Science and Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/44785

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/44785