Magic angle imaging of the Achilles tendon in patients with chronic tendonopathy

AIMS: To assess the Achilles tendon in patients with chronic tendonopathy using magnetic resonance (MR) magic angle imaging, and to compare the appearances and uptake of contrast medium in abnormal tendons with those in normal tendons. MATERIAL AND METHODS: Eight patients with chronic Achilles tendonopathy and five normal controls were examined with the long axis of the tendon placed at 55degrees and at 0degrees to the main magnetic field. Conventional two-dimensional (2D) multi-slice images were obtained and T1 values were calculated before, and for up to 1 h after the administration of intravenous gadodiamide. Both the unenhanced appearance and the pattern of enhancement in the tendon were compared. RESULTS: In the patients with tendonopathy, high signal intensity areas were evident on the short T1 inversion recovery (STIR) images obtained at 55degrees in all tendons. Contrast medium enhancement was seen in six tendons and was most obvious on the images obtained at the magic angle. This was initially focal and then spread more diffusely within the tendon. After contrast medium administration, T1 values were significantly reduced in the tendonopathy group compared with normal controls (p < 0.01). On the late post-contrast medium images obtained at 55degrees, enhancement was evident in most of the tendon and correlated well with high signal intensity seen on STIR images. CONCLUSION: The use of magic angle MR imaging improved the demonstration of signal changes in the Achilles tendon in chronic tendonopathy. The STIR images obtained at the magic angle showed more obvious signal change than those obtained at 0degrees. The changes due to enhancement were much more evident on images obtained at 55degrees than at 0degrees. The uptake of contrast medium was greater in the patients than in normal controls. Oatridge, A. et al. (2003). Clinical Radiology 58, 384-388. (C) 2003 The Royal College of Radiologists. Published by Elsevier Science Ltd. All rights reserved.