Vetter Sebastian, Köhler Hans-Peter, Hepp Pierre, Steinke Hanno, Schleifenbaum Stefan, Theopold Jan, Kiem Simon, Witt Maren, Henkelmann Jeanette, Roth Christian
Sports Faculty Department of Biomechanics in Sports, Leipzig University, Leipzig, Germany.
Department of Orthopedics, Trauma and Plastic Surgery, Universitätsklinikum, Leipzig University, Leipzig, Germany.
PLoS One. 2023 Sep 21;18(9):e0286280. doi: 10.1371/journal.pone.0286280. eCollection 2023.
The ability of muscle to generate force depends on its architecture and health condition. MR-based diffusion tensor imaging of muscle (mDTI) is an innovative approach for showing the fiber arrangement for the whole muscle volume. For accurate calculations of fiber metrics, muscle segmentation prior to tractography is regarded as necessary. Since segmentation is known to be operator dependent, it is important to understand how segmentation affects tractography. The aim of this study was to compare the results of deterministic fiber tracking based on muscle models generated by two independent operators. In addition, this study compares the results with a segmentation-free approach. Fifteen subjects underwent mDTI of the right shoulder. The results showed that mDTI can be successfully applied to complex joints such as the human shoulder. Furthermore, operator segmentation did not influence the results of fiber tracking and fascicle length (FL), fiber volume (FV), fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity (RD), and mean diffusivity (MD) showed excellent intraclass correlation estimates (≥ 0.975). As an exploratory approach, the segmentation-free fiber tracking showed significant differences in terms of mean fascicle length. Based on these findings, we conclude that tractography is not sensitive to small deviations in muscle segmentation. Furthermore, it implies that mDTI and automatic segmentation approaches or even a segmentation-free analysis can be considered for evaluation of muscle architecture.
肌肉产生力量的能力取决于其结构和健康状况。基于磁共振成像的肌肉扩散张量成像（mDTI）是一种用于显示整个肌肉体积内纤维排列的创新方法。为了准确计算纤维指标，在进行纤维束成像之前进行肌肉分割被认为是必要的。由于已知分割依赖于操作者，了解分割如何影响纤维束成像很重要。本研究的目的是比较基于两位独立操作者生成的肌肉模型进行确定性纤维追踪的结果。此外，本研究还将结果与一种无需分割的方法进行了比较。15名受试者接受了右肩部的mDTI检查。结果表明，mDTI可以成功应用于人体肩部等复杂关节。此外，操作者分割并未影响纤维追踪结果，束状长度（FL）、纤维体积（FV）、分数各向异性（FA）、轴向扩散率（AD）、径向扩散率（RD）和平均扩散率（MD）显示出极好的组内相关估计值（≥0.975）。作为一种探索性方法，无需分割的纤维追踪在平均束状长度方面显示出显著差异。基于这些发现，我们得出结论，纤维束成像对肌肉分割中的小偏差不敏感。此外，这意味着可以考虑使用mDTI和自动分割方法，甚至无需分割的分析来评估肌肉结构。
