Waterval N F J, Meekes V L, Hooijmans M T, Froeling M, Jaspers R T, Oudeman J, Nederveen A J, Brehm M A, Nollet F
Amsterdam UMC, University of Amsterdam, Department of Rehabilitation Medicine, Amsterdam Movement Sciences, Meibergdreef 9, Amsterdam, the Netherlands.
Amsterdam UMC, University of Amsterdam, Department of Rehabilitation Medicine, Amsterdam Movement Sciences, Meibergdreef 9, Amsterdam, the Netherlands.
Clin Biomech (Bristol). 2022 Apr;94:105609. doi: 10.1016/j.clinbiomech.2022.105609. Epub 2022 Mar 1.
Progression of plantar flexor weakness in neuromuscular diseases is usually monitored by muscle strength measurements, although they poorly relate to muscle function during walking. Pathophysiological changes such as intramuscular adipose tissue affect dynamic muscle function independent from isometric strength. Diffusion tensor imaging and T2 imaging are quantitative MRI measures reflecting muscular pathophysiological changes, and are therefore potential biomarkers to monitor plantar flexor functioning during walking in people with neuromuscular diseases.
In fourteen individuals with plantar flexor weakness diffusion tensor imaging and T2 scans of the plantar flexors were obtained, and the diffusion indices fractional anisotropy and mean diffusivity calculated. With a dynamometer, maximal isometric plantar flexor strength was measured. 3D gait analysis was used to assess maximal ankle moment and power during walking.
Fractional anisotropy, mean diffusivity and T2 relaxation time all moderately correlated with maximal plantar flexor strength (r > 0.512). Fractional anisotropy and mean diffusivity were not related with ankle moment or power (r < 0.288). T2 relaxation time was strongly related to ankle moment (r = -0.789) and ankle power (r = -0.798), and moderately related to maximal plantar flexor strength (r < 0.600).
In conclusion, T2 relaxation time, indicative of multiple pathophysiological changes, was strongly related to plantar flexor function during walking, while fractional anisotropy and mean diffusivity, indicative of fiber size, only related to maximal plantar flexor strength. This indicates that these measures may be suitable to monitor muscle function and gain insights into the pathophysiological changes underlying a poor plantar flexor functioning during gait in people with neuromuscular diseases.
神经肌肉疾病中跖屈肌无力的进展通常通过肌力测量来监测，尽管这些测量与行走时的肌肉功能相关性较差。肌肉内脂肪组织等病理生理变化会独立于等长肌力影响动态肌肉功能。扩散张量成像和T2成像都是反映肌肉病理生理变化的定量MRI测量方法，因此有可能作为监测神经肌肉疾病患者行走时跖屈功能的生物标志物。
对14名跖屈肌无力患者进行了跖屈肌的扩散张量成像和T2扫描，并计算了扩散指数分数各向异性和平均扩散率。使用测力计测量最大等长跖屈肌力。采用三维步态分析评估行走过程中的最大踝关节力矩和功率。
分数各向异性、平均扩散率和T2弛豫时间均与最大跖屈肌力呈中度相关（r > 0.512）。分数各向异性和平均扩散率与踝关节力矩或功率无关（r < 0.288）。T2弛豫时间与踝关节力矩（r = -0.789）和踝关节功率（r = -0.798）密切相关，与最大跖屈肌力中度相关（r < 0.600）。
总之，反映多种病理生理变化的T2弛豫时间与行走时的跖屈功能密切相关，而反映纤维大小的分数各向异性和平均扩散率仅与最大跖屈肌力相关。这表明这些测量方法可能适用于监测肌肉功能，并有助于深入了解神经肌肉疾病患者步态中跖屈功能不良背后的病理生理变化。
