目的应用基于体素分析(VBA)方法的磁共振扩散张量成像(DTI)技术对内侧颞叶癫痫(mTLE)患者脑微观结构的改变进行观察,探讨其在mTLE神经病理机制研究及定侧诊断中的价值。资料与方法16例单侧mTLE患者及23名健康成年人对照组纳人本研究。在1.5TMR扫描仪下行16个方向的单次激发回波平面成像序列(EPI)的DTI数据采集。采用基于VBA的SPM2软件对两组受试者表观扩散系数(ADC)图及各向异性分数(FA)图进行随机效应分析的两样本t检验比较,观察患者相对正常人AI)C值及FA值发生显著性改变(P〈0.01)的脑区。结果相比正常人,患者ADC增高区表现在患侧内外颞叶、部分额叶、顶叶和脑干结构,以及患侧丘脑等部位;其中大部分脑区同时也表现为FA值的降低,少部分脑区仅表现为FA值减低。比较ADC及FA值两种结果,发现前者在癫痫病灶定侧方面具有更好的效果。结论DTI是一种敏感的影像技术,可用于颞叶癫痫(TLE)定侧及癫痫脑网络结构的研究,有助于对TLE病理生理机制理解,并具有潜在的临床应用价值。
Objective To observe the micro-structural brain abnormalities in the patients with mesial temporal lobe epilepsy (mTLE) using voxei-based diffusion tensor imaging (DTI). To explore the neural pathological mechanism in mTLE and the diagnostic value of diffusion tensor imaging in lateralization of the epileptogenic focus. Materials and Methods Sixteen patients with mTLE and twenty-three healthy controls were scanned with conventional MRI and DTI at GE signal 1.5T MR scanner. The maps of apparent diffusion coefficient (ADC) and fractional anisotropy (FA) in the patients were compared to those in the controls by using voxel-based analysis respectively. Significant differences in diffusivity or ani- sotropy were detected at a threshold of P 〈 0.01 (corrected). Results Compared with the controls, the patients showed increased ADC in the mesial and lateral temporal lobe ipsilateral to the side of epileptogenic focus, bilateral parietal lobe and brain stem, as well as the thalamus ipsilateral to the side of epileptogenic focus. On the other hand, regions showing decreased FA were mostly overlapped with the regions showing increased ADC. Neither decreased ADC nor increased FA was detected in the present study. Laterality of epileptogenie cortex was more prominent in ADC than that in FA. Conclusion DTI has potential for applications in lateralization of the epileptogenie focus and investigation of changes in structural connectivity, and is significant for clinical diagnosis and investigation of the pathophysiological mechanism of mTLE.