Analysis of the BOLD characteristics in pass-band balanced steady state free precession functional magnetic resonance imaging
Abstract/Contents
- Abstract
- Magnetic resonance imaging (MRI) is a powerful medical imaging modality that provides unique and flexible tissue contrast. MRI provides anatomical images, and also provides other capabilities such as measuring physiological changes such as neuronal activation. Since Ogawa et al. suggested oxygenation level as a contrast mechanism underlying the correlation between brain activation and image intensity of gray matter in MRI, various methods have been proposed to improve the contrast. Currently, Gradient Echo (GRE) Echo Planar Imaging (EPI) is most widely-used for the purpose. Balanced Steady-State Free Precession (bSSFP) has recently been proposed as an alternative method to acquire BOLD contrast. Pass-band bSSFP fMRI utilizes the T2 sensitivity of bSSFP in a relatively wide and flat off-resonance frequency band of the bSSFP profile. The method has a potential to provide higher SNR efficiency with reduced imaging artifacts compared to conventional approaches. Previous experimental results suggested that the level of the functional contrast and its characteristics are significantly influenced by the sequence parameters. However, few of these contrast characteristics have been investigated systematically. In this study, a computer simulation was performed to investigate the sources of functional contrast and the influence of scan parameters on the functional contrast to elucidate the contrast characteristics of pass-band bSSFP fMRI. The results suggest that both intravascular T2 change and extravascular spin diffusion are contrast sources with the intravascular contribution covering more than 60% of the total signal change. The extravascular contrast is the main source of small vessel specificity in the pass-band bSSFP fMRI. The pass-band bSSFP fMRI with short TR is most sensitive to vessels with 2 to 5 [mu]m radius, equivalent to human brain capillary size. The extravascular contrast of the pass-band bSSFP fMRI also depends on flip angle, B0 field, and TE. Experiments were performed to validate the simulation results.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2012 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Kim, Taek Soo |
|---|---|
| Associated with | Stanford University, Department of Electrical Engineering |
| Primary advisor | Nishimura, Dwight George |
| Primary advisor | Pauly, John (John M.) |
| Thesis advisor | Nishimura, Dwight George |
| Thesis advisor | Pauly, John (John M.) |
| Thesis advisor | Gold, Garry E |
| Advisor | Gold, Garry E |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Taek Soo Kim. |
|---|---|
| Note | Submitted to the Department of Electrical Engineering. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2012. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2012 by Taek Soo Kim
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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