Tension‐Dependent Variability and Repeatability of Achilles Tendon UTE‐T 2 * Mapping Using Mono‐ and Bi‐Exponential Models

作者：Ananya Goyal, Marco Barbieri, Valentina Mazzoli, Feliks Kogan · 发表于：NMR in Biomedicine · 年份：2026 · DOI：10.1002/nbm.70302 · 研究领域：Tendon Structure and Treatment、Shoulder Injury and Treatment、Bone health and osteoporosis research

ABSTRACT Quantitative MRI using ultrashort echo time (UTE)‐T 2 * mapping is sensitive to collagen‐bound water and tendon microstructure, enabling noninvasive assessment of tendon integrity and laxity. However, the extent to which UTE‐T 2 * measures reflect changes in tendon tension, and their repeatability, remain incompletely understood. We evaluated the sensitivity of mono‐ and bi‐exponential UTE‐T 2 * measures of the Achilles tendon to changes in tendon tension induced by ankle positioning and assessed the test–retest repeatability of these metrics across repeated scan sessions. In this study, healthy adult volunteers underwent UTE‐MRI of the Achilles tendon at two scan sessions, spaced 1 week apart, with the ankle positioned in dorsiflexion (higher tendon tension) and plantarflexion (lower tendon tension). Mono‐exponential T 2 * (T 2 * mono ) and bi‐exponential parameters (T 2 * short , T 2 * long , and short‐component fraction ρ short ) were quantified. We performed a two‐way repeated‐measures ANOVA to assess the main effects of ankle position and scan session, and their interaction. Repeatability was evaluated using root mean square error (RMSE), coefficient of variation (CV%), and Bland–Altman analysis. We observed that short‐component T 2 * metrics demonstrated significant sensitivity to tendon tension. A main effect of ankle position was observed for T 2 * mono ( p < 0.001) and T 2 * short ( p = 0.02), with lower values in dorsiflexion compared with plantarflexion...