SWI对急性失血性贫血兔模型脑改变的实验性研究

SWI of Brain on Acute Hemorrhagic Anemia: An Experimental Study in Rabbits

目的探讨急性失血性贫血兔模型不同脑区磁敏感加权成像(SWI)信号值的变化。方法对10例新西兰大白兔急性失血性贫血模型行MRI扫描,测量SWI图像上双侧额叶皮层,额叶白质、颞叶皮层及丘脑核团的信号强度,并通过半定量方式评价脑灰白质对比度及静脉结构现象的情况。结果大白兔放血前大脑额叶皮层基础SWI信号值高于额叶白质,有统计学差异(F=117.04,P=0.01);经过连续放血后,兔的额叶皮层、颞叶皮层及丘脑灰质的SWI信号值均低于放血前基础SWI信号值,有统计学差异(F=8.10,P=0.01;F=7.67,P=0.01;F=6.72,P=0.02)。在半定量分析中,急性失血性贫血的大白兔在连续放血后其脑灰白质对比度及静脉结构的显示均优于放血前基础图像。结论 MRI SWI能反映急性失血性贫血的状态下,大脑皮质、灰质核团及白质不同的病理生理改变。

Objective To investigate susceptibility weighted imaging （SWI） signal changes in different brain regions in a rabbit model of acute hemorrhagic anemia. Methods Ten New Zealand white rabbits were used for construction of the model of acute hemorrhagic anemia. Signal intensities of SWI images of the bilateral frontal cortex, frontal white matter, temporal lobe and thalamic nuclei were measured. In addition, the cerebral gray white contrast and venous structures of the SWI images were evaluated by experienced physician. Results In normal status, the SWI signal intensity was significant- ly higher in the frontal cortex than in the frontal white matter （63.10±22.82 vs. 52.50±20.29 ; P 〈 0.05）. Repeated bloodletting （ five occasions） caused significant （ P 〈 0.05 ） decreases in the SWI signals of the frontal cortex （ from 63.10±22.82 to 37.70±4.32）, temporal lobe （from 52.50±20.29 to 42.60±5.54） and thalamus （from 60.40±20.29 to 39.40±3.47）, but was without effect in the frontal white matter. The cerebral white gray contrast and venous structures were clearer after bloodletting than before bloodletting. Conclusion The effect of acute hemorrhagic anemia on the brain is reflected by SWI signal changes in the cerebral cortex and gray matter nuclei.