1997 Fiscal Year Final Research Report Summary
A study of functional MRI on whole brain measured by EPI sequence
| Project/Area Number |
07557069
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
Radiation science
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| Research Institution | UNIVERSITY OF TOKUSHIMA |
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Principal Investigator |
NISHITANI Hiromu The University of TOKUSHIMA School of Medicine, Professor, 医学部, 教授 (50117206)
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| Co-Investigator(Kenkyū-buntansha) |
MIYOSHI Hirokazu The University of TOKUSHIMA School of Medical Sciences, Research Associate, 医療短期大学部, 助手 (90229906)
HARADA Masafumi The University of TOKUSHIMA University Hospital, Assistant Professor, 医学部・附属病院, 講師 (20228654)
YOSHIZAKI Kazuo The University of TOKUSHIMA School of Medicine, Professor, 医学部, 教授 (50079696)
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| Project Period (FY) |
1995 – 1997
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| Keywords | fMRI / frequency / brain / language / mapping |
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| Research Abstract |
(1) functional MRI of 1.5T and 4T
We compared mapping results and time courses of intensity in same subjects using 4T and and 1.5T insturments. The statistical analysis was also conducted in the same manner and suitable thresh hold depending on differences of magnetic field strength was considerdd. The short memory task was applied to the same subjects on different days using two instruments. The BOLD effect at 4T was larger than that at 1.5T,but less than the theoretical expression. However the cerebral activated areas were presented in the almost same pattern two instruments and the multiphasic pattern of time signal intensity course was observed on 4T and 1.5T.We considered that even 1.5T would be as useful as 4T to detect function activity of the brain.
(2) 1/f fluctuation of fMRI intensities
The frequency analysis was conducted to the time intensity courses of MRI and the relationship with the inverted frequency was studied. The frequency component of MRI single on both phantom and human had the inverted proportional part to the frequency and the power of frequency. The activation by task study caused perturbation from such a inverted frequency relationship. We considered that the deviation from the inverted frequency relationship showed functional activity and the extent of this deviation would reflect strength of activation.
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