Application of Diffusion-weighted and Perfusion Magnetic Resonance Imaging in Hyperacute Cerebral Infarction Reperfusion in Rats: Comparison to Histopathology

Objective To assess the role of combination diffusion weighted and perfusion magnetic resonance imaging in evaluating on a experimental model of hyperacute cerebral infarction reperfusion in rat and compare to pathological observation.Materials and Methods All 50 SD rats were randomly divided into 5 groups, group A (n=10) was shamoperated for control study, group B, C, D, E (n=10 for each) were divided according to time intervals of 30 minutes, 1 hour, 3 hours, 6 hours after occluding the left middle cerebral artery with thread and reflowed at each time end point at the onset of the occlusion. All rats were examined by diffusion weighted imaging (DWI), perfusion imaging (PI), T 1WI, T 2WI, ADC, CBF, CBV, MTT and pathological observation during their occlusion and 2, 24 h after reperfusion.Results Rats in A group were no change in the intensity of DWI, PI, T 1WI and T 2WI or by pathological examination; in B group, it can be seen that the initial DWI hyperintensity shadow disappeared and ADC recovery at 2 hours after reperfusion following by secondary DWI hyperintensity and ADC decrease at 24 hours after reperfusion. In C group, ADC slightly went up at 2 hours after reperfusion and decreased markedly at 24 hours later. In D,E groups, ADC had a small decrease or unchanged after reflow. In all groups, lesion volume on DWI was not enlarged after reperfusion. Although parameters (CBV,CBF, MTT) values of PI in B, C group recovered and remained normal, in D, E groups had 3 typical fashions of appearance after reperfusion: Hyperperfusion, hypoperfusion and normal perfusion respectively. The abnormal volume demonstrated by DWI after reperfusion showed no difference with that on TTC (t test, P0.05).Conclusion The resolution of initial DWI abnormal signal intensity is transient, and secondary abnormal signal on DWI occurs later after reperfusion in 30 minutes of MCAO; Neuronal necrosis can be observed in areas of the initial DWI abnormal signal resolution at 24 hours after reperfusion. Ischemic penumbra can be protected by recanalization in hyperacute cerebral infarction.