犬实验性脊髓损伤后病理学改变与MRI对比研究

Characteristics of Experimental Spinal Cord Injury and Correlation between Its Pathological Change and Manifestations on MRI in Dogs

目的研究脊髓损伤(SCI)后MRI特点与病理改变的时间关系。方法采用Allen法制成犬SCI模型,分别在损伤后1d、1周、2周、4周、16周观察MRI与病理改变,并测定其行为学与后肢诱发电位变化。结果SCI后1d,动物双后肢肌力均为0级,记录不到明显的诱发电位。此后动物双下肢肌力逐渐恢复;伤后1周诱发电位开始出现,但潜伏期明显延长,随后潜伏期逐渐缩短;SCI后4周,行为学与诱发电位测定恢复均进入平台期,脊髓中央出现空腔,MRI能准确反映SCI后脊髓中央囊腔的形状与位置,T2WI表现边界清楚的高信号影。结论SCI后4周作为慢性SCI的时间定位界限,MRI检查结果尤其是T2WI能够准确反映囊腔的形态,为治疗慢性SCI处理囊腔的定位与范围判断提供实验依据。

Objective To study characteristics of spinal cord injury （SCI） and the correlation of its manifestation on MRI with its pathological change in dogs. Methods The SCI model was established by modified Allen＇s method in dogs. The manifestation of injured spinal cord on MRI and the changes in pathology, electrophysiology and animals behaviors were observed 1 day, 1 week, 2 weeks, 4 weeks and 16 weeks after SCI. Results The presence of high signal on MRI 4 weeks after SCI implied the formation of cyst. One day after SCI, the muscle strength of both the posterior limbs belonged in grade 0, and no motor evoked potential （MEP） and somatosensory evoked potential （SEP） were recorded. And then the muscle strength gradually recovered. One week after SCI, both the MEP and SEP began to appear, but their latent periods were significantly postponed. And then the latent periods of both the MEP and SEP were gradually shortened. The behavior manifestation, MEP and SPE were relatively stable 4 week after SCI. Conclusions MRI is very a useful tool in observing the formation of cyst, and is very helpful to assessing the timing stages of chronic SCI, too.