Neuroscience Research Australia, Sydney, NSW, Australia; University of New South Wales, Sydney, NSW, Australia.
Neuroscience Research Australia, Sydney, NSW, Australia; University of New South Wales, Sydney, NSW, Australia.
J Biomech. 2019 Mar 27;86:71-78. doi: 10.1016/j.jbiomech.2019.01.043. Epub 2019 Jan 30.
For detailed analyses of muscle adaptation mechanisms during growth, ageing or disease, reliable measurements of muscle architecture are required. Diffusion tensor imaging (DTI) and DTI tractography have been used to reconstruct the architecture of human muscles in vivo. However, muscle architecture measurements reconstructed with conventional DTI techniques are often anatomically implausible because the reconstructed fascicles do not terminate on aponeuroses, as real muscle fascicles are known to do. In this study, we tested the reliability of an anatomically constrained DTI-based method for measuring three-dimensional muscle architecture. Anatomical magnetic resonance images and diffusion tensor images were obtained from the left legs of eight healthy participants on two occasions one week apart. Muscle volumes, fascicle lengths, pennation angles and fascicle curvatures were measured in the medial and lateral gastrocnemius, soleus and the tibialis anterior muscles. Averaged across muscles, the intraclass correlation coefficient was 0.99 for muscle volume, 0.81 for fascicle length, 0.73 for pennation angle and 0.76 for fascicle curvature. Measurements of muscle architecture obtained using conventional DTI tractography were highly sensitive to variations in the stopping criteria for DTI tractography. The application of anatomical constraints reduced this sensitivity significantly. This study demonstrates that anatomically constrained DTI tractography can provide reliable and robust three-dimensional measurements of whole-muscle architecture. The algorithms used to constrain tractography have been made publicly available.
为了详细分析生长、衰老或疾病过程中的肌肉适应机制，需要可靠的肌肉结构测量方法。扩散张量成像（DTI）和 DTI 示踪技术已被用于在体重建人类肌肉的结构。然而，由于所重建的肌束不能像真实的肌束那样终止于腱膜，因此常规 DTI 技术重建的肌肉结构通常在解剖学上是不合理的。在这项研究中，我们测试了一种基于解剖约束的 DTI 方法测量三维肌肉结构的可靠性。从八名健康参与者的左腿在一周内两次获得解剖磁共振图像和扩散张量图像。在腓肠肌内侧和外侧、比目鱼肌和胫骨前肌中测量肌肉体积、肌束长度、肌纤维羽状角和肌束曲率。平均而言，肌肉体积的组内相关系数为 0.99，肌束长度为 0.81，肌纤维羽状角为 0.73，肌束曲率为 0.76。使用常规 DTI 示踪技术测量的肌肉结构测量值对 DTI 示踪技术的停止标准变化非常敏感。解剖约束的应用显著降低了这种敏感性。这项研究表明，基于解剖约束的 DTI 示踪技术可以提供可靠和稳健的整体肌肉结构的三维测量。用于约束示踪的算法已经公开。
