颞叶内侧结构弥散张量成像及白质纤维束成像在颞叶癫痫诊断中的应用价值

目的 通过磁共振弥散张量成像(DTI)及白质纤维束示踪(DTT)技术定量分析颞叶癫痫患者双侧颞叶内侧结构弥散参数值及局部纤维束变化特点,评价DTI技术对颞叶癫痫的诊断价值.方法 对广州医学院第二附属医院自2010年12月至2011年2月临床诊断为颞叶癫痫的16例患者和20例健康志愿者进行常规MRI及DTI扫描,测量双侧颞叶杏仁体、海马及颞叶皮质的部分各向异性(FA)、相对各向异性(RA)、表观弥散系数(ADC)等数值并进行统计学分析,同时应用DTT技术观察癫痫患者局部纤维束与正常对照者的差异.结果 正常对照者双侧颞叶内侧各结构FA、RA、ADC值比较差异均无统计学意义(P＞0.05).颞叶癫痫患侧、对侧与正常对照者颞叶内侧各结构FA、RA、ADC值比较差异均有统计学意义(P＜0.05),其中ADC值呈颞叶癫痫患侧＞颞叶癫痫对侧＞正常对照者的变化趋势,以海马尾部变化最为显著；而FA、RA值呈颞叶癫痫患侧＜颞叶癫痫对侧＜正常对照者的变化趋势,并且杏仁体、海马体部变化较海马尾部更显著.结论 DTI技术能充分了解癫痫患者颞叶内侧结构的弥散参数值及纤维束变化特点,有助于癫痫病灶定位的准确诊断,同时加深对颞叶内侧结构整体变化的了解亦有助于术前的整体评估及提高手术疗效.

MR diffusion tensor imaging and MRI diffusion-tensor tracking of medial structures of the temporal lobe in the diagnosis of temporal lobe epilepsy

Objective To investigate the parameter values and changes of local fiber bundles of the medial structures of the temporal lobe in patients with temporal lobe epilepsy(TLE) with MR diffusion tensor imaging(DTI)and MRI diffusion-tensor tracking(DTT),and evaluate the diagnostic value of DTI in the localization of seizure focus in patients with TLE:Methods Sixteen patients with TLE,admitted to our hospital from December 2010 to February 2011,and 20 healthy volunteers received conventional MRI and DTI.The values of apparent diffusion coefient(ADC),fractional anisotropy(FA)and relative anisotropy(RA) of the bilateral medial structures of the temporal lobe (including the amygdala,hippocampus and cortex)were measured,respectively.The differences of the fiber bundles between the epilepsy patients and the controls were observed with DTT.Results No significant differences in measured values of ADC,FA and RA were noted between the left and right medial structures of temporal lobe in the controls(P＞0.05).The values of ADC,FA and RA in the left/right medial structures of temporal lobe in TLE patients had significant differences as compred with those in controls(P＜ 0.05); the values of ADC showed gradual reduction in the ipsilateral side,contralateral side and controls,successively; and the changes in the hippocampus tail was the most obvious.The values of FA and RA showed gradual increment in the ipsilateral side,contralateral side and controls successively;the changes of parameters values in the amygdala and the hippocampus body were more remarkable than those in the hippocampus tail.Conclusion The DTI can show the micromechanics′ characteristics of the medial structures of the temporal lobe in patients with TLE,which can help the location of seizure focus in patients with TLE.Increasing the understanding of the medial structures of the temporal lobe will help the preoperative integral assessment and improve the surgical effect.