Division of Neurology, Department of Medicine, University of Alberta, Edmonton, Canada.
Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada.
Brain Behav. 2023 Jul;13(7):e3102. doi: 10.1002/brb3.3102. Epub 2023 Jun 6.
To evaluate the degeneration of the corticospinal tract (CST) and corpus callosum (CC) in patients with motor neuron disease and upper motor neuron (UMN) dysfunction using diffusion kurtosis imaging (DKI).
Twenty-seven patients and 33 healthy controls underwent magnetic resonance imaging along with clinical and neuropsychological testing. Tractography of diffusion tensor images was performed to extract tracts of the bilateral CST and CC. Group mean differences both across the entire averaged tract and along each tract were assessed, including correlations between diffusion metrics and clinical measures. Tract-based spatial statistics (TBSS) was performed to evaluate the spatial distribution of whole-brain microstructural abnormalities in patients.
In comparison to controls, patients had significantly higher mean and radial diffusivity and lower fractional anisotropy (FA), kurtosis anisotropy, mean kurtosis (MK), and radial kurtosis (RK) in the CST and CC (p < .017). Along-the-tract analysis revealed changes concentrated in the posterior limb of the internal capsule, corona radiata, and primary motor cortex (false-discovery rate p < .05). FA of the left CST correlated with disease progression rate, whereas MK of the bilateral CST correlated with UMN burden (p < .01). TBSS results corroborated along-tract analysis findings and additionally revealed reduced RK and MK in the fornix, where diffusion tensor imaging (DTI) changes were absent.
DKI abnormalities in the CST and CC are present in patients with UMN dysfunction, potentially revealing complementary information to DTI regarding the pathology and microstructural alterations occurring in such patients. DKI shows promise as a potential in vivo biomarker for cerebral degeneration in amyotrophic lateral sclerosis.
使用扩散峰度成像（DKI）评估运动神经元病和上运动神经元（UMN）功能障碍患者皮质脊髓束（CST）和胼胝体（CC）的退变。
27 名患者和 33 名健康对照者接受了磁共振成像以及临床和神经心理学测试。对弥散张量图像进行了轨迹追踪，以提取双侧 CST 和 CC 的轨迹。评估了整个平均轨迹和每条轨迹的组间差异，包括扩散指标与临床指标之间的相关性。进行基于束的空间统计学（TBSS）分析以评估患者全脑微观结构异常的空间分布。
与对照组相比，患者的 CST 和 CC 的平均弥散度和径向弥散度明显升高，各向异性分数（FA）、峰度各向异性、平均峰度（MK）和径向峰度（RK）明显降低（p<0.017）。沿轨迹分析显示，变化主要集中在内囊后肢、放射冠和初级运动皮层（假发现率 p<0.05）。左侧 CST 的 FA 与疾病进展速度相关，而双侧 CST 的 MK 与 UMN 负担相关（p<0.01）。TBSS 结果证实了沿轨迹分析的结果，并进一步显示了穹窿和双侧 CST 的 RK 和 MK 降低，而弥散张量成像（DTI）的变化则不存在。
UMN 功能障碍患者的 CST 和 CC 存在 DKI 异常，这可能为这些患者的病理和微观结构改变提供了与 DTI 互补的信息。DKI 有望成为肌萎缩侧索硬化症中脑退行性变的潜在体内生物标志物。
