Contrast-enhanced magic-angle MR imaging of the Achilles tendon

The objective of this study was to image the Achilles tendon with MR imaging at the magic angle (the long axis of the tendon at 55 degrees relative to the direction of the main static magnetic field [B(0)]) to detect signal from the tendon, to measure the T1 of the tendon, and to determine patterns of contrast enhancement in control subjects and patients.

Mean T1 values of 311 +/- 30 msec (at 1.0 T) were found in six volunteers. In six control volunteers, slow uptake of contrast material that dispersed over 40 min-1.5 hr was shown without focal change, with elimination in most cases occurring within 18-24 hr. Small rapidly enhancing focal areas of enhancement were seen next to the insertion of the tendon and centrally within 5-10 min in two control volunteers. The focal areas were located at the sites of the blood supply. A patient with chronic tendinopathy showed early local contrast enhancement that extended widely within the tendon over several hours. Two patients with a partially ruptured or repaired tendon showed marked rapid contrast enhancement. The enhancement was obvious with the tendon at the magic angle but was not evident with the tendon in the usual orientation for MR examinations parallel to B(0).