In vivo time course studies of the tissue responses to resorbable polylactic acid implants by means of MRI

Magnetic resonance (MR) imaging and relaxation time measurements of bioreso rbable implants made of polylactic acid (PLA), as well as the surrounding t issues, were carried out over a period of 6 months to monitor the implant s tate and the body's responses, and to determine how these processes are ref lected in MR data. Twelve rabbits each received two subcutaneous PLA implan ts (45 x 10 x 2 mm). Changes in tissue relaxation rates demonstrated inflam mation and tissue healing time courses but were not simply linear functions of the tissue water content and so provide new insight into MR characteriz ation of inflammatory processes. Magn Reson Med 42:210-214, 1999. (C) 1999 Wiley-Liss, Inc.