Achilles tendon injuries are common but challenging to monitor during recovery due to the limitations of current imaging techniques. Researchers, led by Associate Professor Zeng Nan from the International Graduate School at Shenzhen, Tsinghua University, have applied Mueller matrix polarimetry, a non-invasive imaging method, to more accurately observe and evaluate the healing of Achilles tendon injuries. This technique offers unique insights by capturing the subtle changes in tendon tissue without needing labels or dyes, allowing for more natural tissue characterization.

The study used Mueller matrix polarimetry to assess various Achilles tendon samples, comparing injured tissues with those undergoing treatment. The findings revealed specific patterns in injured tendons, such as decreased phase retardance and increased diattenuation, as well as irregular fiber orientation. Healthy tendons, by contrast, showed higher phase retardance and a more consistent fiber arrangement, markers indicative of strong, undamaged tissue.

By combining experimental results with Monte Carlo simulations, the study highlighted three key recovery indicators: fiber diameter growth, improved alignment, and increased birefringence due to collagen production. A new parameter, called PFP, was developed based on these observations, offering a practical tool for visualizing and quantifying tendon healing progress. This breakthrough, spearheaded by Professor Zeng Nan’s team, could have significant implications for clinical practice, as it allows for precise, real-time assessment of treatment efficacy for Achilles tendon injuries. The work entitled “Mueller matrix polarimetry for quantitative evaluation of the Achilles tendon injury recovery” was published on Frontiers of Optoelectronics (published on Dec. 9, 2024).
DOI: 10.1007/s12200-024-00142-2