| Research Abstract |
We developed the Line Scan Diffusion Image (LSDI) pulse sequence to make a less signal distorted water diffusion coefficient image and to measure a precise diffusion coefficient of brain free water. This pulse sequence can also apply to measure a multi-exponential signal decay. We used GE SIGNA MRI scanner (General Electric Medical Systems) for the pulse program development.
We compared the diffusion images of the same slice plane by both methods of the LSDI and EPI pulse sequence to clarify the ability of LSDI for the less distorted image. In the EPI method which using a gradient echo pulse sequence, the image near an Air-Tissue interface which like a paranasal cavity area is obviously distorted by the effect of T2^*. This result is reported at International *ociety for Magnetic Resonance in Medicine, 7^<th> Scientific Meeting, Philadelphia, USA in 1999 and at Japan Society for Magnetic Resonance in Medicine, 28^<th> Meeting, Kyoto, JAPAN in 2000. In our LSDI method which can be used for a multi-exponential signal decay, it is possible to measure twenty different signals observed in different diffusion gradient fields at one scan protocol. Although we tried to observe the multi-exponential signal decay of brain free water diffusion, the signal could not identify as slow diffusing water because of the low SN ratio of LSDI signal. We, however, observed the signal fluctuation seems to be caused by brain pulsation. In the future, it is possible to visualize the effect of pulsation by using LSDL method.
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