Magnetic resonance spectroscopic imaging with 2D spectroscopy for the detection of brain metabolites
Year: 2012
Type: dissertation
Abstract: While magnetic resonance imaging (MRI) derives its signal from protons in water, additional biochemical compounds are detectable in vivo within the proton spectrum.The detection and mapping of these much weaker signals is known as magnetic resonance spectroscopy or spectroscopic imaging.Among the complicating factors for this modality applied to human clinical imaging are limited chemical-shift dispersion and J-coupling, which cause spectral overlap and complicated spectral shapes that limit detection and separation of brain metabolites using MR spectroscopic imaging (MRSI).Existing techniques for improved detection include so-called 2D spectroscopy, where additional encoding steps aid in the separation of compounds with overlapping chemical shift.This is achieved by collecting spectral data over a range of timing parameters and introducing an additional frequency axis.While these techniques have been shown to improve signal separation, they carry a penalty in scan time that is often prohibitive when combined with MRSI.Beyond scan time constraints, the lipid signal contamination from the subcutaneous tissue in the head pose problems in MRSI.Due to the large voxel size typical in MRSI experiments, ringing artifacts from lipid signals become more prominent and contaminate spectra in brain tissue.This is despite the spatial separation of subcutaneous and brain tissue.This thesis first explores the combination of a 2D MRS method, Constant Time Point REsolved SpectroScopy (CT-PRESS) with fast spiral encoding in order to achieve feasible scan times for human in-vivo scanning.Human trials were done on a 3.0T scanner and with a 32-channel receive coil array.A lipid giving me advice and words of encouragement even when we are separated by thousands of miles.I look forward to seeing them again in Singapore.I am heartily thankful to the friends outside of academia who made my Boston and MIT experience extraordinary.The instructors and students at Firebeat Dancesport Studios and on the MITBDT showed true dedication in doing what they love.There are too many to list here but I would like to thank them for helping me balance work and play.I also thank the Japanese Sports Meetup members for their friendship and for ensuring that my Sundays are always adrenaline-pumping.The Singaporeans at MIT have given me much support and laughter.I would like to specifically thank
Author: Trina Kok
Language: English
Subfield: Radiology, Nuclear Medicine and Imaging
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W1509874967