磁共振弥散张量成像评估早期创伤性轴索损伤的价值

The value of MR diffusion tensor imaging in evaluating acute traumatic axonal injury

目的探讨磁共振弥散张量成像(DTI)对早期创伤性脑损伤(TBI)患者轴索损伤的临床应用价值。方法对21例TBI早期(伤后10d内)患者(TBI组)及10例正常志愿者(对照组)行DTI检查,分别测量两侧大脑半球6个感兴趣区(胼胝体膝部、胼胝体压部、内囊前肢、内囊后肢、外囊及背侧丘脑)的部分各向异性(FA)值,并构建上述部位三维弥散张量纤维束成像(3D-DTT)图。比较以上两组感兴趣区平均FA值的差异,并对TBI组的FA值与临床GCS评分进行相关性分析。结果 FA图像上可以清楚观察到呈高信号的脑白质纤维束,损伤局部呈低信号。TBI组平均FA值为0.562±0.042,明显低于对照组的0.609±0.045(P<0.01)。TBI患者FA值与GCS评分呈正相关(r=0.508,P<0.05)。3D-DTT图可以直观显示胼胝体、内外囊等白质纤维束的损伤情况。结论 FA值的变化反应了TBI患者脑白质纤维束水分子各向异性程度的变化,对评估伤情及判断预后有重要意义。

Objective To investigate the significance of MR diffusion tensor imaging（DTI） in evaluating acute axonal injury of traumatic brain injury（TBI）.Methods DTI examination was performed in 21 patients with acute TBI（group A） and 10 volunteers（group B）.The FA values in the 6 interest regions were measured,which were genu of the corpus callosum,splenium of the corpus callosum,anterior limb of the internal capsule,posterior limb of the internal capsule,external capsule and dorsal thalamus.The FA values between two groups were compared and the correlation of the FA value and clinical glasgow coma score（GCS） was analyzed.Results The cerebral white matter fibers in group A could be clearly showed on FA maps with the local low intensity of the injuried parts.The FA value was lower in group A than that in group B（0.562±0.042 vs.0.609±0.045）（P〈0.01）.The FA value in group A was positively correlated with GCS（r=0.508,P〈0.05）.3D-DTT showed that the injuried fibers lost their normal shape.Conclusion The changes of fractional anisotropy reflect the changes of cerebral white matter fibers,which is useful in evaluating the injury and predicting the prognosis of patients with TBI.