Dynamic 3-T MRI can show and measure peroneal tendon motion during active ankle movement with good image quality in healthy volunteers. A prospective pilot study in European Radiology Experimental assessed real-time imaging during active dorsiflexion and plantarflexion at the lateral malleolus. Ten adults without ankle symptoms or previous ankle trauma underwent dynamic ankle MRI, while three musculoskeletal radiologists rated image quality and one radiologist measured tendon motion from segmented images. Peroneal tendon movement was visible in all volunteers, and repeated measurements of the distance between the peroneus longus and peroneus brevis tendons showed good reliability.
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Dynamic Imaging Targets a Diagnostic Gap
Peroneal tendon disorders are a frequent but under-recognised cause of lateral ankle pain. Injuries to the anterior talofibular and calcaneofibular ligaments can be associated with peroneus brevis tears and lateral ankle instability. The superior peroneal retinaculum may also be injured. Peroneal tendon instability and longitudinal split tears can be difficult to diagnose because symptoms and tendon movement may appear only in certain positions or during motion.
Static imaging can miss instability when the abnormal movement is not present during the scan. Dynamic assessment can show how the tendons behave during active ankle movement, rather than only showing their position at rest. Ultrasound already offers real-time evaluation and remains the preferred first-line test for suspected peroneal instability, but it depends strongly on examiner experience. Results can also be harder to standardise and review later.
Dynamic 3-T MRI offers a different form of functional assessment. It provides cross-sectional images during motion and creates a record that can be reviewed after the examination. The approach is not intended to replace ultrasound or routine MRI. Instead, it may help in selected cases where symptoms suggest tendon instability but static MRI is unclear or where ultrasound findings are difficult to reproduce. Previous dynamic MRI work has mainly focused on larger joints, joint motion or lower-resolution imaging, rather than detailed peroneal tendon movement during active ankle motion.
Protocol Produces Reviewable Tendon Motion
The pilot included ten healthy adult volunteers with no ankle pain, previous ankle trauma, ankle surgery or MRI contraindications. Imaging took place at Sahlgrenska University Hospital in Gothenburg, Sweden. Before scanning, volunteers received standardised instructions on slow dorsiflexion and plantarflexion. Their foot movement was monitored in real time with a camera, allowing rhythm and movement to be adjusted during acquisition.
The lower leg and ankle were supported with cushions and sandbags to limit unwanted movement while still allowing the ankle to move freely. Dynamic imaging was performed in the axial plane at the lateral malleolus, a common site for peroneal tendon instability, dislocation and split tears. The real-time sequence produced 70 frames during a 60-second scan. The same sequence was repeated four times in each examination. The added time for instruction, positioning and dynamic imaging was approximately eight minutes.
Three experienced musculoskeletal radiologists independently assessed image quality using five criteria. These covered artefacts, visibility of tendon contours, visibility of the fibula and superior peroneal retinaculum, ability to follow tendon motion and confidence in excluding tendon luxation. For the motion analysis, the best-rated series was selected. The peroneus longus and peroneus brevis tendons were manually segmented, and the distance between their centroids was calculated in each frame. This provided a simple time-based measure of how the tendons moved in relation to each other during ankle motion.
Image Quality and Motion Metrics Support Feasibility
Image quality was good across the assessed criteria. Median scores were at least 4 on a five-point scale, while mean scores were just above 4. Diagnostic confidence and tendon contour sharpness received the highest total ratings. Agreement between readers was strongest for visibility of the superior peroneal retinaculum and the ability to follow tendon motion. Optional comments mainly noted occasional motion-related blurring, ghosting or partial-volume effects. No rater reported artefacts that prevented diagnostic interpretation.
All volunteers completed continuous self-paced plantarflexion and dorsiflexion during the dynamic scans. They usually completed four to five movement cycles during each 60-second scan. Peroneal tendon motion was visible in every volunteer. The distance between the peroneus longus and peroneus brevis tendons increased during dorsiflexion and decreased during plantarflexion. The range of movement between the tendons varied between volunteers, and repeated segmentation after one month showed good intra-rater reliability.
The results support technical feasibility but do not establish diagnostic performance. The sample was small, single-centre and limited to healthy volunteers. It remains unknown whether the same protocol works as well in patients with pain, limited range of motion or suspected instability. The motion measurements also used manual segmentation by one radiologist, so wider reproducibility was not assessed. Imaging was limited to one axial level, ankle angles were not directly measured, and self-paced motion could vary between volunteers. Future evaluation will need symptomatic patients, comparison with ultrasound and clinical or surgical reference standards, and more practical segmentation methods.
Dynamic ankle 3-T MRI can show peroneal tendon motion during active movement with good image quality in healthy volunteers. The approach provides reviewable functional information during dorsiflexion and plantarflexion, with reproducible measurement of tendon movement in this pilot setting. It may complement ultrasound and static MRI in future assessment of suspected peroneal tendon instability. Routine use is not yet supported, because diagnostic accuracy, clinical value, reproducibility in symptomatic patients and workflow practicality still need to be confirmed.
Source: European Radiology Experimental
Image Credit: iStock
References:
Mocanu D, Phoemsawang CN, Papalini EI et al. (2026) Real-time 3-T MRI of peroneal tendon motion during active ankle movement: feasibility and image quality. Eur Radiol Exp; 10, 99.
