An Experimental Study Of Ischemic Penumbra In Rabbits With Magnetic Resonance Diffusion And Perfusion Weighted Imaging

Objective To explore the value of diffusion weighed imaging (DWI) and perfusion weightedimaging (PWI) in the diagnosis of the ischemic penumbra (IP) slavaged. Methods 58 successfulmodels of middle cerebral artery occlusion (MCAO) with New Zealand rabbits were randomlydivided into permanent ischemic group (A group) consisting of 30 cases and ischemic reperfusiongroup (B group) consisting of 28 cases. The first group was further divided into ischemic 1h, 3h,6h, 12h, 24h, 48h groups (A_1～6 group), averagely consisting of 5 cases. The second group wasfurther divided into reperfusion 1h, 2h, 5h, 11h, 23h, 47h groups (B_1～6 group) consisting of 5, 5, 5,4, 5, 4 cases respectively. Another 10 rabbits were regarded as ischemic contrast and reperfusioncontrast, each group consist of 5 cases. Then every group was examed with modalities includingDWI and PWI. To analyze the changes of abnormal signal intensity area on DWI in order toexplore the evolutional rule of the extent of IP slavaged, and the goal of studying the changes ofADC, rCBV, rMTT ratio in different region of interest (ROI) was to have a quantitive analysis ofslavagable IP. Result On one hand, the area of the abnormal signal intensity on DWI in ischemicreperfusion group was significantly smaller than that in permanent ischemic group at the sametime, confirming that there was some IP slavaged; At ischemic 24h, the area of infarction getsmoothly, and the mismatch area between A group and B group attached closely to the extent of IPslavaged. On the other hand, the change of ADC, rCBV and rMTT ratio in different region ofinterest was helpful to indicate whether it was IP or necrosis; At ischemic 1h, if the ADC, rCBV,rMTT ratio of region of interest changed respectively during (73.40±4.33)%, (46.83±8.06)% and 1.58±0.04, it might be IP, but if the ADC, CBV ratio of region of interest changed belowrespectively 62.82%, 28.25%, and the rMTT ratio of region of interest was higher than 1.87, itwould become infaction. Conclusion Combined with DWI and PWI could evaluate quickly andefficiently IP slavaged.