An experimental study on acute cerebral ischemia and reperfusion with magnetic resonance diffusion weighted imaging of rabbits

Objective To discuss the changes of magnetic resonance diffusion weighted imaging(DWI) in acute middle cerebral artery occlusion ischemia and reperfusion(MCAOI/R)in rabbits.Methods 58 successful MCAO models were randomly divided into permanent ischemic group(n=30) which were further averagely subdivided into ischemic 1,3,6,12,24,48 h group and ischemic reperfusion group(n=28) which were divided into reperfusion 0,2,5,11,23,47 h group consisting respectively 5,5,5,4,5,4 cases.Another 10 rabbits were averagely divided into ischemic contrast and reperfusion contrast.The changes of hyperintensity area on DWI and apparent diffusion coefficient(ADC) were measured respectively in different groups.Results All rabbits showed hyperintensity area on DWI with declined ADC following ischemic 1 h.The mean ADC of each time point in ischemic group declined at first and then gradually increased.Compared with ischemic 1 h,the hyperintensity area on DWI in other time points was obviously enlarged and became steadily after 24 h in ischemic group.Compared with ischemic 1 h,hyperintensity area decreased in reperfusion 2,5 h groups,increased in reperfusion 11,23 and 47 h groups;ADC increased in reperfusion 2,5 and 11 h groups and decreased in reperfusion 23 and 47 h groups.Conclusions The hyperintensity area and the decreased ADC in acute cerebral ischemia could be improved by early reperfusion,but continuous reperfusion could induce the secondary decreased ADC.