University of Oxford Centre for Functional Magnetic Resonance of the Brain, John Radcliffe Hospital, Oxford, UK.
Neurology. 2010 Nov 2;75(18):1645-52. doi: 10.1212/WNL.0b013e3181fb84d1.
While the hallmark of amyotrophic lateral sclerosis (ALS) is corticospinal tract in combination with lower motor neuron degeneration, the clinical involvement of both compartments is characteristically variable and the site of onset debated. We sought to establish whether there is a consistent signature of cerebral white matter abnormalities in heterogeneous ALS cases.
In this observational study, diffusion tensor imaging was applied in a whole-brain analysis of 24 heterogeneous patients with ALS and well-matched healthy controls. Tract-based spatial statistics were used, with optimized voxel-based morphometry of T1 images to determine any associated gray matter involvement.
A consistent reduction in fractional anisotropy was demonstrated in the corpus callosum of the ALS group, extending rostrally and bilaterally to the region of the primary motor cortices, independent of the degree of clinical upper motor neuron involvement. Matched regional radial diffusivity increase supported the concept of anterograde degeneration of callosal fibers observed pathologically. Gray matter reductions were observed bilaterally in primary motor and supplementary motor regions, and also in the anterior cingulate and temporal lobe regions. A post hoc group comparison model incorporating significant values for fractional anisotropy, radial diffusivity, and gray matter was 92% sensitive, 88% specific, with an accuracy of 90%.
Callosal involvement is a consistent feature of ALS, independent of clinical upper motor neuron involvement, and may reflect independent bilateral cortical involvement or interhemispheric spread of pathology. The predominantly rostral corticospinal tract involvement further supports the concept of independent cortical degeneration even in those patients with ALS with predominantly lower motor neuron involvement clinically.
虽然肌萎缩侧索硬化症（ALS）的标志是皮质脊髓束与下运动神经元变性相结合，但两个部位的临床受累特征性地不同，发病部位也存在争议。我们试图确定在异质性 ALS 病例中是否存在脑白质异常的一致特征。
在这项观察性研究中，我们对 24 名异质性 ALS 患者和匹配良好的健康对照者进行了全脑弥散张量成像分析。使用基于束的空间统计学，对 T1 图像进行优化体素形态计量学，以确定任何相关的灰质受累。
ALS 组胼胝体的各向异性分数明显降低，向头侧和双侧延伸至初级运动皮质区域，与临床上上运动神经元受累的程度无关。匹配的区域放射状弥散度增加支持了胼胝体纤维进行性变性的概念。双侧初级运动和辅助运动区、扣带回和颞叶区也观察到灰质减少。纳入各向异性分数、放射状弥散度和灰质有显著意义的事后组比较模型的敏感性为 92%，特异性为 88%，准确性为 90%。
胼胝体受累是 ALS 的一个一致特征，与临床上的上运动神经元受累无关，可能反映了独立的双侧皮质受累或病理学的半球间传播。主要的皮质脊髓束受累向头侧进一步支持了即使在临床上主要表现为下运动神经元受累的 ALS 患者中也存在独立皮质变性的概念。
