Reliability and robustness of muscle architecture measurements obtained using diffusion tensor imaging with...

Area of Science:

• Biomedical Engineering
• Human Anatomy
• Medical Imaging

Background:

• Accurate muscle architecture analysis is crucial for understanding growth, aging, and disease.
• Conventional diffusion tensor imaging (DTI) tractography often yields anatomically implausible muscle fascicle reconstructions.
• Fascicles must realistically terminate on aponeuroses, a limitation not met by standard DTI.

Purpose of the Study:

• To evaluate the reliability of an anatomically constrained DTI-based method for in vivo 3D muscle architecture measurement.
• To compare the robustness of constrained DTI against conventional DTI tractography.
• To provide reliable quantitative data on muscle architecture parameters.

Main Methods:

• Acquired anatomical and diffusion tensor images of lower leg muscles (medial/lateral gastrocnemius, soleus, tibialis anterior) from eight healthy participants.
• Applied an anatomically constrained DTI tractography method to reconstruct 3D muscle architecture.
• Measured muscle volume, fascicle length, pennation angle, and fascicle curvature, assessing reliability via intraclass correlation coefficients (ICC).

Main Results:

• The anatomically constrained method demonstrated high reliability across all measured parameters (ICC ≥ 0.73).
• Intraclass correlation coefficients were 0.99 for muscle volume, 0.81 for fascicle length, 0.73 for pennation angle, and 0.76 for fascicle curvature.
• Constrained DTI significantly reduced sensitivity to tractography stopping criteria compared to conventional DTI.

Conclusions:

• Anatomically constrained DTI tractography provides reliable and robust 3D measurements of whole-muscle architecture in vivo.
• This method overcomes limitations of conventional DTI, offering more plausible fascicle reconstructions.
• Publicly available algorithms facilitate broader application of this advanced technique for muscle research.