肌萎缩侧索硬化症的扩散张量成像研究

Exploration of the degeneration in the brain of amyotrophic lateral sclerosis by diffusion tensor MR imaging

目的采用DTI技术,定量检测肌萎缩侧索硬化症(ALS)患者脑内上运动神经元(UMN)的受累情况。方法运用GE Signa3.0T磁共振成像系统,对15例临床确诊及拟诊的ALS患者和12例性别、年龄相当的正常对照者进行了全脑DTI扫描。分别计算双侧大脑皮层下白质、皮质脊髓束及胼胝体各部的各向异性分数(FA)和平均扩散系数(MD),并与多种临床参数进行相关分析。结果ALS患者脑内的FA值在双侧中央前后回皮层下白质、放射冠、内囊后肢后部、大脑脚及胼胝体各部较正常对照者显著下降;而相应部位的MD值无显著变化。FA值与ALSFRS及最大手指敲击率呈正相关,与病程、年龄及病情进展速度呈负相关;MD值与ALSFRS、病情进展速度及年龄呈负相关,而与其他临床指标之间无显著相关性。结论DTI可以通过定量检测ALS患者脑内FA及MD值的变化帮助确定上运动神经元的受累情况,尤其是在临床诊断不是很明确时。

Objective To investigate the involvement of upper motor neuron （UMN） in amyotrophic lateral sclerosis （ALS） patients using diffusion tensor imaging （DTI）. Methods Fifteen patients with clinically probable or definite ALS according to the E1 Escorial criteria and 12 （age and sex-matched） healthy control subjects were studied with the use of DTI. Disease severity was determined by means of the ALS Functional Rating Scale （ALSFRS）. DTI data were acquired with a 25-direction, single-shot, spin-echo echo-planar sequence on GE Signa 3.0T MR system. Fractional anisotropy （FA） and mean diffusivity （MD） were measured in the both sides of the subcortical white matter of pre and post central gyrus, various locations in the corticospinal tract （CST）, and the corpus callosum in ALS patients and control subjects. Results Compared with those of control groups, the FA values of ALS patients reduced significantly in the subcortical white matter of pre and post central gyrus, corona radiata, the posterior part of posterior limb of internal capsule, cerebral peduncle, and corpus callosum; while the MD values in all locations did not change significantly. The FA values correlated positively with ALSFRS and finger-tap rate, and negatively with the disease duration, age and disease progression rate. MD values correlated nega- tively with ALSFRS, age, and disease progression rate, but no correlation were found with the finger-tap rate and disease duration. Conclusion The change of FA and MD values detected by DTI can help to determine the involvement of UMN in ALS patients, especially when the clinical diagnosis is unclear.