Department of Neurology, BG-University Hospital Bergmannsheil, Ruhr-University Bochum, Bochum, Germany.
Department of Neurology, Klinikum Dortmund, University Witten-Herdecke, Dortmund, Germany.
NMR Biomed. 2024 Nov;37(11):e5214. doi: 10.1002/nbm.5214. Epub 2024 Jul 10.
Quantitative muscle magnetic resonance imaging (qMRI) is a valuable methodology for assessing muscular injuries and neuromuscular disorders. Notably, muscle diffusion tensor imaging (DTI) gives insights into muscle microstructural and macrostructural characteristics. However, the long-term reproducibility and robustness of these measurements remain relatively unexplored. The purpose of this prospective longitudinal cohort study was to assess the long-term robustness and range of variation of qMRI parameters, especially DTI metrics, in the lower extremity muscles of healthy controls under real-life conditions. Twelve volunteers (seven females, age 44.1 ± 12.1 years, body mass index 23.3 ± 2.0 kg/m) underwent five leg muscle MRI sessions every 20 ± 4 weeks over a total period of 1.5 years. A multiecho gradient-echo Dixon-based sequence, a multiecho spin-echo T2-mapping sequence, and a spin-echo echo planar imaging diffusion-weighted sequence were acquired bilaterally with a Philips 3-T Achieva MR System using a 16-channel torso coil. Fifteen leg muscles were segmented in both lower extremities. qMRI parameters, including fat fraction (FF), water T2 relaxation time, and the diffusion metrics fractional anisotropy (FA) and mean diffusivity (MD), were evaluated. Coefficients of variance (wsCV) and intraclass correlation coefficients (ICCs) were calculated to assess the reproducibility of qMRI parameters. The standard error of measurement (SEM) and the minimal detectable change (MDC) were calculated to determine the range of variation. All tests were applied to all muscles and, subsequently, to each muscle separately. wsCV showed good reproducibility (≤ 10%) for all qMRI parameters in all muscles. The ICCs revealed excellent agreement between time points (FF = 0.980, water T2 = 0.941, FA = 0.952, MD = 0.948). Random measurement errors assessed by SEM and the MDC were low (< 12%). In conclusion, in this study, we showed that qMRI parameters in healthy volunteers living normal lives are stable over 18 months, thereby defining a benchmark for the expected range of variation over time.
定量肌肉磁共振成像（qMRI）是评估肌肉损伤和神经肌肉疾病的一种有价值的方法。值得注意的是，肌肉扩散张量成像（DTI）可以深入了解肌肉的微观结构和宏观结构特征。然而，这些测量的长期可重复性和稳健性仍相对未知。本前瞻性纵向队列研究的目的是评估健康对照者在现实生活条件下下肢肌肉 qMRI 参数（特别是 DTI 指标）的长期稳健性和变化范围。12 名志愿者（7 名女性，年龄 44.1±12.1 岁，体重指数 23.3±2.0 kg/m）在 1.5 年内每隔 20±4 周进行 5 次腿部肌肉 MRI 检查。使用飞利浦 3-T Achieva MR 系统和 16 通道体线圈，双侧采集多回波梯度回波 Dixon 基序、多回波自旋回波 T2 映射序列和自旋回波 EPI 扩散加权序列。在两个下肢中对 15 条腿部肌肉进行分割。评估 qMRI 参数，包括脂肪分数（FF）、水 T2 弛豫时间和扩散指标各向异性分数（FA）和平均扩散系数（MD）。计算变异系数（wsCV）和组内相关系数（ICC）以评估 qMRI 参数的可重复性。计算测量误差的标准误差（SEM）和最小可检测变化（MDC）以确定变化范围。所有测试均应用于所有肌肉，然后分别应用于每个肌肉。wsCV 显示所有肌肉的所有 qMRI 参数均具有良好的可重复性（≤10%）。ICC 显示各时间点之间具有极好的一致性（FF=0.980、水 T2=0.941、FA=0.952、MD=0.948）。SEM 和 MDC 评估的随机测量误差较低（<12%）。总之，在这项研究中，我们表明生活正常的健康志愿者的 qMRI 参数在 18 个月内是稳定的，从而为随时间变化的预期变化范围定义了一个基准。
