Sensitivity & Repeatability of UTE-T2* Mapping to Tendon Extension and Contraction

Motivation: Tendon laxity, which may cause skeletal maltracking, can lead to pain and increased injury risk. Non-invasive measurement of tendon laxity remains a challenge but Ultrashort echo time (UTE)-T2* mapping may serve as a potential evaluation method. Goal(s): This study aims to evaluate the sensitivity and repeatability of UTE-T2* mapping to tendon laxity. Approach: We scanned the Achilles tendons of human subjects under tension and relaxation using UTE sequences. Results: T2* relaxation times seemed to decrease as tendon load increased, from plantar flexion to dorsiflexion. However, the changes observed were small and intra-subject variability with position did not show any specific trends. Impact: As the changes in T2* relaxation times were small and showed poor reproducibility, UTE-T2* mapping may not be sensitive enough to changes in tendon tensile loading and laxity.