轻度创伤性脑损伤患者动态扩散张量成像的演变规律

目的通过观察轻度创伤性脑损伤(TBI)患者DTI动态变化规律,探讨其在反映TBI病理生理学改变、病程发展方面的应用价值.方法对35例轻度TBI患者和35名健康对照者行常规MR、DTI检查.测量TBI患者(急性期、亚急性期、伤后5周～3个月)和对照者多个脑区的FA值、ADC值并进行比较,观察各测量值动态变化规律.结果 轻度TBI患者部分脑叶白质和脑干区的FA值在急性期、亚急性期时减低(P均<0.05),伤后5周～3个月时略低于对照者(P均>0.05),但急性期时胼胝体、内囊的FA值高于对照者(P均>0.05),此后持续减低,在伤后5周～3个月时差异仍具有统计学意义(P均<0.05).ADC值大致呈现为急性期减低,亚急性期及伤后5周～3个月逐渐升高(P均>0.05)的趋势.结论FA值减低反映神经轴索损伤,但急性期轻度TBI患者的胼胝体、内囊处FA值略升高,提示存在细胞毒性<水肿.ADC值反映轴索损伤不及FA值敏感、准确.

Longitudinal imaging of mild traumatic brain injury patientswith diffusion tensor imaging

Objective To observe the spatiotemporal features of DTI in mild traumatic brain injury (TBI) patients, and to explore the significance of DTI in determining the pathophysiological change and monitoring the disease progression of TBI. Methods Thirty-five mild TBI patients and 35 matched healthy controls underwent conventional MRI and DTI. FA values and ADC values in the specific cerebral regions of TBI patients in acute phase, subacute phase, 5 weeks-3 months post-trauma and controls were measured and compared. The temporal changes of MRI data were observed. Results FA values in the part of the lobar white matter and brainstem reduced in the acute and subacute phases of mild TBI patients (all P<0.05), slightly lower than those of the controls (all P>0.05) in 5 weeks-3 months post-trauma phase. As for corpus callosum and internal capsule, the FA values in the acute stage exceptionally mildly elevated (all P>0.05) and decreased thereafter. Even in 5 weeks-3 months post-trauma phase, their FA values still were significantly different compared with healthy controls (all P<0.05). ADC values significantly decreased within acute stage and went up thereafter (all P>0.05). Conclusion The decreased FA values indicates the injury of axons. FA values of corpus callosum and internal capsule in the acute phase exceptionally increase in the mild TBI patients, suggesting the presence of cytoxic edema. ADC is not as sensitive nor accurate as FA values in reflecting the injury of axons.