BROWSE

ITEM VIEW & DOWNLOAD

Robust assessment of quantitative magnetic resonance imaging as an imaging biomarker at 7 Tesla

Cited 0 times inthomson ciCited 0 times inthomson ci
Title
Robust assessment of quantitative magnetic resonance imaging as an imaging biomarker at 7 Tesla
Other Titles
7 Tesla에서 이미징 바이오 마커로서 정량적 자기 공명 영상법의 강력한 평가
Author
Lee, Dongkyu
Advisor
Cho, Hyungjoon
Keywords
magnetic resonance relaxations; magnetic resonance spatial resolution; trabecular structure; vessel size imaging (VSI); stimulated echo (STE); compressed sensing; T1 measurements; turbo-spin echo (TSE); rapid acquisition with refocused echoes (RARE)
Issue Date
2020-02
Publisher
Graduate School of UNIST
Abstract
Magnetic susceptibility contrast MRI using local magnetic field gradients or inhomogeneities is expected to provide low-resolution quantification of tissue microarchitecture, as magnetic resonance (MR) transverse relaxation times (T2 and T2*) are influenced by field inhomogeneity arising from susceptibility mismatch of tissues. By aid of ultra-high field MRI scanner, MR transverse relaxation times is promising to further increase their sensitivity to detecting subtle structural changes in tissue microstructures. However, one of the main technical difficulty of ultra-high field MRI is unwanted variations of signal and contrast, or even worse, nullify the MR signal due to increased macroscopic static magnetic field inhomogeneities which are prone to misinterpretation and loss of structural information. This study focuses on improving the sensitivity and the robustness of ultra-high field MRI (particularly for 7 T) from unwanted signal variations due to magnetic field inhomogeneities and shortened MR transverse relaxation times. MR transverse relaxation times were investigated for the low-resolution assessment of tissue microstructures, such as trabecular bone microstructure and cerebral microvasculature. As a result, T2 relaxation time without having an effect of macroscopic field inhomogeneities may be suitable for the assessment of trabecular structural indices and robust with degrading spatial resolution with reduced scan time at 7 T. For the assessment of cerebral microvasculature, the diffusion-time-dependent stimulated-echo-based MR relaxation-rates was demonstrated as robust measures for assessing small (diameter < 5 μm) cerebral microvasculature, where macroscopic field inhomogeneities from bone (air)-tissue interfaces and influences of large vessels in cortical region are significant. Finally, the quantification of MR longitudinal relaxation time (T1) was optimized by variable repetition-delay turbo-spin echo method with sparse encoding technique.
Description
Department of Biomedical Engineering
URI
Go to Link
Appears in Collections:
BME_Theses_Ph.D.
Files in This Item:
Robust assessment of quantitative magnetic resonance imaging as an imaging biomarker at 7 Tesla.pdf Download

find_unist can give you direct access to the published full text of this article. (UNISTARs only)

Show full item record

qrcode

  • mendeley

    citeulike

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

MENU