Magnetic resonance: magic angle imaging of the Achilles tendon

Tendons do not normally produce detectable signals with conventional magnet ic-resonance techniques and are recognised as dark signal voids. However, i f tendons are examined at 55 degrees to the static magnetic field (the "mag ic angle"), signals become detectable and the tendons can become the bright est structure on the Image. We have used this approach to establish tendon relaxation times and magnetisation transfer ratios and to show contrast enh ancement. We have also shown more detail of acute and chronic tendon ruptur e by this method compared with images made with the tendon parallel to the static magnetic field.