Imaging of the rabbit supraspinatus enthesis at 7 Tesla: a 4-week time course after repair surgery and effect of channeling.

Purpose: To image the supraspinatus enthesis reformation of rabbit shoulders by magnetic resonance at 7 Tesla (T) using T2 mapping after surgical repair and to assess the effects of channeling aimed at enhancing enthesis reformation.

Materials And Methods: In 112 rabbits, the distal supraspinatus (SSP) tendon was unilaterally detached and reattached after 1 week. At the first surgery, channeling was performed at the footprint in 64 rabbits. At the second surgery, the SSP tendon of all rabbits was re-attached to the greater tuberosity. The shoulders were harvested at 0, 1, 2, or 4 weeks after the repair surgery and were imaged at 7T. Quantitative T2 mapping was performed using multi slice two-dimensional multi-echo spin-echo sequence with fat saturation. Enthesis regions of interests were drawn on three slices at the footprint to measure T2 relaxation times.

Results: Tendon repair (F  = 44; P < 2.2e-16) and postoperative duration (F  = 4.8; P = 0.006) both affected significantly the T2 values while channeling had no significant effect. For the time effect, the only pair with a statistical difference was the 0-week and 4-week for the channeling groups (P = 0.023).

Conclusion: Enthesis reformation early after surgical repair of the SSP distal tendon was characterized by increasing T2 values.

Level Of Evidence: 2 Technical Efficacy: Stage 1 J. MAGN. RESON. IMAGING 2017;46:461-467.