胼胝体挫伤的磁共振扩散张量成像研究

目的 评价磁共振扩散张量纤维束成像技术在脑外伤所引起的胼胝体纤维损伤中的临床应用价值. 资料与方法 12名健康志愿者和23例脑外伤患者进行常规MRI及扩散张量成像(DTI)检查,通过运算获得大脑白质纤维的各向异性(fractional anisotropy,FA)图、平均扩散系数(average diffusion coefficient,DCavg)图、容积比异向性(volume ratio anisotropy,VrA)图、各向同性(isotropic image,Iso)图等,分别测量经内囊层面胼胝体前部、胼胝体后部的FA、DCavg值,并进行比较. 结果 在FA图像上正常人胼胝体呈均匀高信号显示清晰,23例脑外伤中胼胝体正常7例,FA值正常;局灶胼胝体挫伤14例,FA值下降14例,DCavg下降14例,胼胝体弥漫挫伤2例,T1 FLAIR序列显示胼胝体肿胀变形,FA图胼胝体纤维失去正常结构及形态,类似斑片状,FA值下降. 结论 DTI能精确、直观地显示胼胝体纤维,在评价脑外伤后胼胝体损伤方面有较高的应用价值,尤其对弥漫性轴索损伤及患者预后的评估更有意义.

Study of Diffusion Tensor Imaging in the Contusion of Corpus Callosum

Objective To evaluate the clinical value of diffused fibrous bands MRI in detecting fibrous injury of corpus callosum caused by cerebral trauma. Materials and Methods Routine MRI and DTI examination were performed in 12 normal volunteers and 23 cases of cerebral trauma. Fractional anisotropy(FA), average diffusion coefficient(DCavg), volume ratio anisotropy(VrA), and isotropic image(Iso) were obtained. FA, and Dcavg of anterior part and posterior part of corpus callosum were measured respectively. FA, and Dcavg of anterior part were compared with that of posterior part. Results On FA image, corpus callosum of normal subjects showed clear high signal. In 23 trauma cases, 7 cases had normal corpus callosum and normal FA value. Local corpus callosum was contused with FA and Dcavg decreased in 14 cases. Corpus callosum was diffusely contused in 2cases. T1 FLAIR sequence showed corpus callosum was transfigured and swollen, FA showed that fibrous corpus callosum was disfigured and similar to patch, FA value was decreased. Conclusion DTI can directly and clearly display corpus callosum fiber, which is of great value in evaluating corpus callosum injury, especially diffused axonal injury following cerebral trauma and the prognosis.