Abstract: Biexponential diffusion of water in rat brain before and after picrotoxin induced epilepsy was reported for the first time based on MRI study at 4.7T. Self-comparision of the same rat (n=3) in the normal condition and after injection of picrotoxin shows that diffusion coefficients of both fast and slow diffusion components of water were reduced by 16.0% and 23.5%, respectively. Although the proton density was unchanged, the content ratio of the fast and slow diffused water was increased from 1.3:1 to 1.8:1 after the inducement of epilepsy. This may be the source of the increase in transverse relaxation time of water in the epilepsic rat brain.

Key words: MRI, Biexponential diffusion, Epilepsy