Diffusion tensor imaging for the assessment of upper motor neuron integrity in ALS
Diffusion tensor imaging for the assessment of upper motor neuron integrity in ALS
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DOI：
10.1212/01.wnl.0000145766.03057.e7
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发表时间：
2004-12-14
期刊：
影响因子：
9.9
通讯作者：
Griffiths, PD
中科院分区：
文献类型：
--
作者：
Graham, JM;Papadakis, N;Griffiths, PD
背景资料：高角分辨率扩散张量成像（HARD）是一种MRI技术，它利用水分子的流动性来产生白色物质束的结构顺序和方向性图，其精度高于六向扩散张量成像（DTI）方案。目的：评估HARD在检测ALS患者上运动神经元（UMN）病理方面是否比常规MRI或神经学评估更敏感。方法：对25例有明确临床表现的UMN患者和23例健康志愿者进行常规MRI检查。从这些参与者的一个子集加上4名具有孤立性下运动神经元（LMN）体征的患者中收集HARD数据集。ALS症状严重程度由神经科医生评估，常规MR图像由神经放射科医生审查，DTI图进行定量感兴趣区分析。结果如下：T2加权像上运动皮质低信号和质子密度加权像上放射冠高信号区分UMN受累患者和志愿者的特异性为100%，但敏感性仅为20%。与志愿者相比，UMN受累患者内囊后肢的各向异性分数（FA）降低。检测ALS患者（包括孤立LMN体征的患者）的灵敏度为95%的FA阈值的特异性为71%。结论：高角分辨率弥散张量成像可能比常规MRI或神经病学评估更敏感，但缺乏诊断标记物所需的特异性。相反，它是潜在的有用的定量工具，用于监测UMN病理的进展。
Background: High angular resolution diffusion tensor imaging (HARD) is an MRI technique that exploits the mobility of water molecules to yield maps of structural order and directionality of white matter tracts with greater precision than six-direction diffusion tensor imaging (DTI) schemes. Objective: To assess whether HARD is more sensitive than conventional MRI or neurologic assessment in detecting the upper motor neuron (UMN) pathology of patients with ALS. Methods: Twenty-five patients with definite UMN clinical signs and 23 healthy volunteers underwent conventional MRI. HARD datasets were collected from a subset of these participants plus four patients with isolated lower motor neuron (LMN) signs. ALS symptom severity was assessed by a neurologist, the conventional MR images were reviewed by neuroradiologists, and the DTI maps were subject to quantitative region of interest analysis. Results: Motor cortex hypointensity on T2-weighted images and corona radiata hyperintensity on proton density-weighted images distinguished patients with UMN involvement from volunteers with 100% specificity, but only 20% sensitivity. Fractional anisotropy ( FA) was reduced in the posterior limb of the internal capsule in patients with UMN involvement compared to volunteers. A FA threshold value with a sensitivity of 95% to detect patients with ALS ( including those with isolated LMN signs) had a specificity of 71%. Conclusions: High angular resolution diffusion tensor imaging may be more sensitive than conventional MRI or neurologic assessment to the upper motor neuron ( UMN) pathology of ALS, but it lacks the specificity required of a diagnostic marker. Instead, it is potentially useful as a quantitative tool for monitoring the progression of UMN pathology.