Abstract：Objective: To explicit the dynamic changes of average diffusion coefficient(DCav), Isotropic image(Iso), fractional anisotropy(FA), relative anisotropy(RA), anisotropy index(AI) value in acute cerebral ischemia. Materials and Methods: Twelve male SD rats were divided into four groups randomly: group A: cerebral ischemia 1h(3 rats), group B: cerebral ischemia 1.5h(3 rats), group C: cerebral ischemia 3h(3 rats), group D: cerebral ischemia 6h(3 rats). MRI in the prescriptive time and the cerebral TTC stain in 24h were performed. The values of Iso signal, DCav, FA, RA, and AI in the lesion and control region were measured. Results: The DCav value of left cortical and striatal area were lowered grading 51%～67％ and the isotropic image showed hyperintensity significently in all times. After cerebral ischemia 1h and 1.5h, the FA and RA value in left hemisphere increased slightly, but had no significance with contralateral region. The AI image showed hypointensity in left hemisphere, the ratio of AI value between lesion and contralateral region were 0.50 and 0.46. In 3h and 6h, the FA and RA value of left hemisphere dropped. The AI values were lowered with the ratio of 0.18 and 0.06 between two sides. Conclusions: The MR DTI parameters changes were luxuriant in acute cerebral ischemia.
2007, Vol. 18 
