Bone scanning in assessing viability of vascularized skeletal tissue transplants

One hundred and eight bone scans using 99mTechnetium methylene diphosphonate (MDP) were performed in rats undergoing vascularized and nonvascularized syngeneic and allogeneic transplants of the hind limb, and in control animals. A six-level system of grading the radionuclide uptake in the graft was used to evaluate healing or complications of the transplantation. Bone scanning was superior to other modalities in assessing viability of the graft. Bone scans were able to: (1) immediately confirm vascular patency, thus obviating angiography; (2) demonstrate differences in the rate of repair in syngeneic and allogeneic nonvascularized grafts; (3) sequentially assess vascularized allograft rejection; and (4) document long-term effects, such as bone atrophy due to disuse and early epiphyseal maturity.