碩士 / 長庚大學 / 醫療機電工程研究所 / 100 / Hearing loss induced by the central auditory pathways neural hyperactivity, the spontaneous motivation from auditory cortex may be one of reasons about tinnitus. But the hyperactivity caused by acoustic trauma is still unclear. Study shows heat shock protein in auditory cortex of rats has been changed when noise exposure, it also makes the difference on gene expression. However, the pervious examine needed to invasively adopting sacrifice of animals in order to observe the difference between the normal hearing rats and the hearing impairment rats. So, we try to find a non-invasive way to observe the difference between normal and hearing loss rats.
Using sodium magnetic resonance imaging is the best choice to observe organization. Sodium ion is 0.2% weight of human body, this ion is not only helping us to balance plasma osmotic pressure, but it is also the key of action potential. Every organization has their unique T1, T2 relaxation times.
In this study, we measured the T1, T2 relaxation times to find the characteristic of auditory cortex. The National Taiwan University’s Bruker 7T BioSpec 70/30 USR Preclinical MRI System was utilized to acquire T1, T2 relaxation times of phantom and rats. The sequence was FLASH, and the study was separated into two parts. The 140mM NaCl liquor was used in the phantom, which is the concentration of a normal rat’s brain, and the animal model were only contain the female Sprague Dawley rats weighted between 250 - 300g.
The T1, T2 relaxation times of 140mM NaCl liquor was measured successfully, that the T1 relaxation time is 56.02 ± 2.88 ms and T2 relaxation time is 52.31 ± 2.74 ms. We found that when using the Flash sequence to investigate the phantom experiment, we needed to be award on the effect from flip angle, FA at T1 relaxation time, and the number of excitations, NEX at T2 relaxation time. The values of T1and T2 at the rats’ for auditory cortex were 38.91 ± 8.54 ms and 22.18 ± 6.95 ms, respectively. This study is the first development of technologies on sodium MRI to find T1 and T2 relaxation times at auditory cortex in normal rats. And the further studies could focus on the T1 and T2 of the auditory cortex of the rats with noise exposure.
| Identifer | oai:union.ndltd.org:TW/100CGU05763004 |
| Date | January 2012 |
| Creators | Hui Hung Lin, 林暉閎 |
| Contributors | J. F. Yu, 余仁方 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 110 |
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