3D-TSE-T2加权像纵向观察猫脑皮质脊髓束早期Wallerian变性

A longitudinal 3D-TSE-T2 weighted imaging observation on early Wallerian degeneration of corticospinal tract in cat brain

目的研究猫脑皮质脊髓束早期Wallerian变性(WD)在3D-TSE-T2加权像上信号强度动态变化过程。方法对8只家猫实施单侧皮质脊髓束(CST)起源脑区切除术,选取连续的8个时间点,即建模前、建模后2天、4天、6天、8天、10天、20天、30天进行MRT2加权扫描。通过放置感兴趣区(ROI),分别获得患侧与健侧皮质脊髓束走行区的T2信号强度值(T2s),计算患侧与健侧T2s比值即相对T2信号强度(rT2s)。结果手术后至第4天,T2WI未见明显异常信号,rT2s值相对稳定;第6～10天,T2WI见患侧开始出现异常低信号,rT2s值急剧下降;第10～30天内,患侧仍表现为T2WI明显低信号,rT2s值保持相对稳定,但30天时rT2s值有升高趋势。结论 T2WI能比较敏感地监测早期WD。

Objective To observe the signal intensity dynamic process of early Wallerian degeneration （WD） of the corticospinal tract （CST） in cat brain on 3D-TSE-T2 weighted imaging （3D-TSE-T2WI）. Methods The origin cortex regions of the unilateral CSTs in 8 cats were cut off to establish the models of Wallerian degeneration, and longitudinal T2WI were performed repeatedly at 8 consecutive time points （before modeling and 2, 4, 6, 8, 10, 20 and 30 days after brain surgery）. The values of T2 signal intensity of bilateral CSTs were obtained using a region of interest method. The ratios of T2 signal intensity （rT2s） between the affected and unaffected sides of the CSTs were calculated. Results During the first 4 days, there was no obvious abnormal signal on T2WI, and the rT2s did not change significantly in the degenerated CSTs. From 6 to 10 days, the rT2s decreased progressively with abnormal low signals on T2WI. From 10 to 30 days, the rT2s stabilized relatively still with low signals on T2WI, but on 30th day the rT2s began to increase. Conclusion T2WI can be used to detect early WD sensitively.