MRI and DWI dynamic observation on hypertensive encephalopathy in rabbit models

Objective To investigate the dynamic changes of hypertensive encephalopathy(HTE) of rabbit models with MRI and DWI.Methods Totally 20adult New Zealand white rabbits were randomly divided into group A and B,contained 10rabbits.Modified Gloidblatt 2K1Cwere used in rabbits to establish chronic hypertension model in group A,while intramuscular injection of Metaraminol Bitartrate was performed to build acute hypertension models in group B.Routine brain MRI and DWI were obtained and ADC values were calculated in selected ROI.Variations of signal intensities and ADC values were compared in the anterior,middle and posterior brain regions.Results One rabbit died in group B.Patchy slightly hypo-intensities on T1WI and hyper-intensities on T2WI were observed in posterior brain regions in 9rabbits of group B,which disappeared completely after drug withdrawal for 1week,and slight hyper-intensities or iso-intensities were observed on DWI.ADC values increased with the time of injection going,and arrived to peak after 9days.No positive finding in group A was obtained.Conclusion Vasogenic edema in posterior brain regions is the characteristic presentation of HTE of rabbits.DWI could provide information of distribution and dynamic changes of brain edema.