3.0T弥散张量纤维束成像对颅脑爆震伤的研究价值

Study value of 3.0T diffusion tensor tractography in diagnosis of cerebral blast injury

目的利用弥散张量纤维束成像(DTT)技术,研究颅脑爆震伤后脑白质纤维束的形态和结构改变。方法对30只实验兔执行颅脑爆震,炸后执行常规MRI及弥散张量成像(DTI)扫描,采用Functool2的Tensor软件包对DTI进行校准,在弥散各向异性分数(FA)图基础上对感兴趣区(ROI)重建脑白质纤维束图,解剖实验兔颅脑,进行病理组织学检查,与其DTT图像对照分析。结果 30只实验兔中17只炸后死亡,13只存活,其中2只存活72 h以上。白质纤维束异常改变类型分为4型:编码颜色改变2只;缺失/断裂+移位8只;稀少+缺失/断裂6只;编码颜色改变+缺失/断裂+移位14只。病理组织学检查示毛细血管破裂,毛细血管内皮损伤、出血;神经细胞及神经胶质细胞变性、坏死,神经髓鞘脱失;轴突球形成。结论 DTT能够清晰、直观显示脑白质纤维束损伤情况,尤其是脑白质纤维束微小结构、形态改变,脑白质纤维束形态改变越复杂,存活时间越短。

Objective To investigate the efficacy of diffusion tensor tractography （DTT） in study of changes of cerebral white matter fiber after cerebral blast injury. Methods Cerebral blast was conducted in 30 rabbits, and routine MRI and diffusion tensor imaging （DTI） were performed after injury. DTI was adjusted with Tensor software of Functool2, and cerebral white matter fiber of region of interest （ROI） was reconstructed on the basis of fractional anisotropy images. The cerebral histopathological changes were observed, and contrast analysis was carried out with findings from DTT. Results After blast, 17 rabbits died, and the other 13 survived, among which 2 survived for more than 72 h. There were 4 types of cerebral white matter abnormality, which were color abnormality of ornamental code （ n = 2）, deficiency/breakage ＋ displacement （ n = 8）, rarity ＋ deficiency/breakage （n = 6） and color abnormality of ornamental code ＋ deficiency/breakage ＋ displacement （n = 14）. Pathological examination indicated there was capillary break, capillary endothelial injury and hemorrhage, nerve cell and colloid cell degeneration and necrosis, nerve myelin sheath loss and formation of axon bulb. Conclusion DTT may clearly and directly illustrate the injury of cerebral white matter fiber, especially for the small abnormal cerebral white matter fiber, and more complicated change of cerebral white matter fiber may lead to shorter duration of survival.