Department of Radiology, University of Washington, Seattle, WA, United States of America.
Department of Neurology, University of Washington, Seattle, WA, United States of America.
PLoS One. 2018 Oct 26;13(10):e0206323. doi: 10.1371/journal.pone.0206323. eCollection 2018.
In this study, multi-parametric magnetic resonance imaging (MRI) was conducted to monitor skeletal muscle changes in dystrophic (mdx4cv) and age-matched control (C57BL/6J) mice starting at 3 weeks of age. The objective of this study was to evaluate and characterize changes in muscle tissue characteristics of hind limbs in young, dystrophic mice using MRI. Mdx4cv (n = 25) and age-matched C57BL/6J (n = 5) were imaged at 3, 5, 7, 9, and 11 weeks of age. Multiple MR measurements were taken from the tibialis anterior, gastrocnemius, and soleus muscles. There were significant differences between dystrophic and control groups for all three muscle types when comparing transverse relaxation times (T2) in lower hind limb muscles. Additionally, fractional anisotropy, radial diffusivity, and eigenvalue analysis of diffusion tensor imaging also demonstrated significant differences between groups. Longitudinal relaxation times (T1) displayed no significant differences between groups. The earliest time points in the magnetization transfer ratio measurements displayed a significant difference. Histological analysis revealed significant differences in the tibialis anterior and gastrocnemius muscles between groups with the mdx mice displaying greater variability in muscle fiber size in later time points. The multi-parametric MRI approach offers a promising alternative for future development of a noninvasive avenue for tracking both disease progression and treatment response.
在这项研究中，从 3 周龄开始，对进行性营养不良症（mdx4cv）和年龄匹配的对照（C57BL/6J）小鼠进行多参数磁共振成像（MRI）监测骨骼肌变化。本研究的目的是使用 MRI 评估和描述年轻的进行性营养不良症小鼠后肢肌肉组织特征的变化。在 3、5、7、9 和 11 周龄时对 mdx4cv（n=25）和年龄匹配的 C57BL/6J（n=5）进行成像。从比目鱼肌、腓肠肌和跖肌中采集了多个 MR 测量值。当比较下后肢肌肉的横向弛豫时间（T2）时，三种肌肉类型的进行性营养不良症组和对照组之间均存在显著差异。此外，各向异性分数、径向扩散系数和扩散张量成像的特征值分析也表明组间存在显著差异。纵向弛豫时间（T1）在组间无显著差异。磁化传递比测量的最早时间点显示出显著差异。组织学分析显示，在比目鱼肌和腓肠肌之间，各组之间存在显著差异，mdx 小鼠在后期时间点的肌肉纤维大小变化更大。多参数 MRI 方法为未来开发一种非侵入性的方法来跟踪疾病进展和治疗反应提供了有希望的替代方法。
