Department of Radiology, Cochin Hospital, Université Paris Cité, APHP, Paris, France.
Center for Research in Epidemiology and StatisticS (CRESS), Université Paris Cité and Université Sorbonne Paris Nord, Inserm, INRAE, Paris, France.
J Magn Reson Imaging. 2024 Sep;60(3):1037-1048. doi: 10.1002/jmri.29178. Epub 2023 Dec 15.
MR elastography (MRE) may provide quantitative imaging biomarkers of lumbar back muscles (LBMs), complementing MRI in spinal diseases by assessing muscle mechanical properties. However, reproducibility analyses for MRE of LBM are lacking.
To assess technical failure, within-day and inter-day reproducibility, robustness with the excitation source positioning, and inter-observer agreement of MRE of muscles.
Prospective.
Seventeen healthy subjects (mean age 28 ± 4 years; 11 females).
FIELD STRENGTH/SEQUENCE: 1.5 T, gradient-echo MRE, T1-weighted turbo spin echo.
The pneumatic driver was centered at L3 level. Four MRE were performed during two visits, 2-4 weeks apart, each consisting of two MRE with less than 10 minutes inter-scan interval. At Visit 1, after the first MRE, the coil and driver were removed, then reinstalled. The MRE was repeated. At Visit 2, following the first MRE, only the driver was moved down 5 cm. The MRE was repeated. Two radiologists segmented the multifidus and erector spinae muscles.
Paired t-test, analysis of variance, intraclass correlation coefficients (ICCs). P-values <0.05 were considered statistically significant.
Mean stiffness of LBM ranged from 1.44 to 1.60 kPa. Mean technical failure rate was 2.5%. Inter-observer agreement was excellent (ICC ranging from 0.82 [0.64-0.96] to 0.99 [0.98-0.99] in the multifidus, and from 0.85 [0.69-0.92] to 0.99 [0.97-0.99] in the erector spinae muscles). Within-day reproducibility was fair in the multifidus (ICC: 0.53 [0.47-0.77]) and good in the erector spinae muscles (ICC: 0.74 [0.48-0.88]). Reproducibility after moving the driver was excellent in both multifidus (ICC: 0.85 [0.69-0.93]) and erector spinae muscles (ICC: 0.84 [0.67-0.92]). Inter-day reproducibility was excellent in the multifidus (ICC: 0.76 [0.48-0.89]) and poor in the erector spinae muscles (ICC: 0.23 [-0.61 to 0.63]).
MRE of LBM provides measurements of stiffness with fair to excellent reproducibility and excellent inter-observer agreement. However, inter-day reproducibility in the multifidus muscles indicated that the herein used MRE protocol may not be optimal for this muscle.
2 TECHNICAL EFFICACY: Stage 1.
磁共振弹性成像（MRE）可提供腰椎肌肉（LBM）的定量成像生物标志物，通过评估肌肉力学特性来补充脊柱疾病的 MRI。然而，LBM 的 MRE 重复性分析尚缺乏研究。
评估 LBM 的 MRE 的技术失败率、日内和日间可重复性、激励源定位的稳健性以及观察者间的一致性。
前瞻性研究。
17 名健康受试者（平均年龄 28±4 岁；11 名女性）。
场强/序列：1.5T，梯度回波 MRE，T1 加权涡轮自旋回波。
气动驱动器位于 L3 水平的中心。两次就诊时进行了 4 次 MRE，间隔 2-4 周，每次 MRE 包括两次扫描，两次扫描之间的间隔不到 10 分钟。在第一次 MRE 后，第一次就诊时，首先将线圈和驱动器移开，然后重新安装。重复 MRE。在第二次就诊时，仅将驱动器向下移动 5cm。重复 MRE。两名放射科医生对多裂肌和竖脊肌进行了分段。
配对 t 检验、方差分析、组内相关系数（ICC）。p 值<0.05 被认为具有统计学意义。
LBM 的平均刚度范围为 1.44 至 1.60kPa。平均技术失败率为 2.5%。观察者间的一致性很好（多裂肌的 ICC 范围为 0.82[0.64-0.96]至 0.99[0.98-0.99]，竖脊肌的 ICC 范围为 0.85[0.69-0.92]至 0.99[0.97-0.99]）。多裂肌的日内重复性为中等（ICC：0.53[0.47-0.77]），竖脊肌的重复性良好（ICC：0.74[0.48-0.88]）。驱动器移动后的重复性在多裂肌（ICC：0.85[0.69-0.93]）和竖脊肌（ICC：0.84[0.67-0.92]）中均为优秀。多裂肌的日间重复性很好（ICC：0.76[0.48-0.89]），而竖脊肌的重复性较差（ICC：0.23[-0.61 至 0.63]）。
LBM 的 MRE 提供了具有中等至优秀可重复性和良好观察者间一致性的刚度测量值。然而，多裂肌的日间重复性表明，此处使用的 MRE 方案可能不适合该肌肉。
2 级技术效能。
