Ligaments and tendons of the ankle: Evaluation with low-field (0.2 T) MR imaging

Purpose: To investigate the value of MR imaging using a low-field imaging unit (0.2 T) for the evaluation of ligaments and tendons of the ankle. Material and Methods: Twelve ankle specimens were studied using low-field MR imaging (0.2 T). The Achilles tendon, the tibialis posterior tendon, and the lateral collateral ligaments were evaluated for the presence of degenerative changes and partial and complete tears. Visibility and overall image quality were analyzed by qualitative evaluation. Results: Low-field MR images of the 24 tendons were interpreted as normal in 11 cases, showing degenerative changes in 9 cases and a partial tear in 1 case. Visualization was regarded as not sufficient for a diagnosis in 3 cases. Of the 36 ligaments, 14 were regarded as normal while degenerative changes were seen in 5 cases and a tear in 2 cases. In 13 cases, no diagnosis could be established, and in 2 cases only a probable diagnosis was established. The best overall quality was obtained with the use of Tl spin-echo (680/20/4) and T2 multi-echo (3000/40/1) images. Conclusion: Optimized protocols for examination of the ankle using low-field MR imaging may allow evaluation of the Achilles and tibialis posterior tendons, but these protocols may not be as useful for diagnosing ligamentous changes.