Real-time 3-T MRI of peroneal tendon motion during active ankle movement: feasibility and image quality.

OBJECTIVE

To evaluate the feasibility and image quality of dynamic 3-T magnetic resonance imaging (MRI) for visualizing and quantifying peroneal tendon motion during active dorsiflexion and plantarflexion.

MATERIALS AND

METHODS

This prospective pilot study was approved by the Swedish Ethical Review Authority (Dnr 2020-00029). Asymptomatic adults without prior ankle trauma underwent dynamic ankle MRI at 3 T using a balanced fast field-echo sequence (axial at the lateral malleolus) during active dorsiflexion/plantarflexion. Three musculoskeletal radiologists rated five image-quality criteria (five-point Likert); agreement was quantified with Gwet's AC2 and Fleiss' κ. The highest-rated sequence was analyzed. One musculoskeletal radiologist manually segmented the peroneus longus and peroneus brevis tendons; Euclidean centroid distance was computed per frame. For intra-rater analysis, an independent person randomly selected three volunteers; segmentation was repeated after 1 month, and reliability was assessed with the intraclass correlation coefficient (ICC) (2,1).

RESULTS

Ten volunteers aged 36.6 ± 7.8 years (mean ± stasndard deviation) were included. Tendon motion was visualized in all volunteers with good image quality (median 4; mean 4.04-4.10). Agreement was strongest for retinaculum visibility and ability to follow tendon motion (AC2 = 0.621 and 0.557, respectively). Centroid distance increased in dorsiflexion and decreased in plantarflexion (excursion 2.95-4.83 mm). Intra-rater reliability was good (ICC = 0.85; 95% confidence interval 0.723-0.922; p < 0.001).

CONCLUSION

Dynamic MRI enabled reproducible, high-quality visualization and quantification of peroneal tendon motion during active ankle movement and warrants evaluation in suspected peroneal tendon instability.

RELEVANCE STATEMENT: Dynamic real-time 3-T MRI enables visualization and quantitative tracking of peroneal tendon motion during active ankle movement, and may complement static imaging in future studies of suspected peroneal tendon instability.

KEY POINTS: Real-time 3-T MRI showed peroneal tendon motion in all volunteers. Image quality was consistently good for tracking tendons during ankle movement. Centroid-to-centroid distance between tendons was highly repeatable over time.