Quantitative radionuclide imaging for early determination of fate of mandibular bone grafts

Clinical assessment of bone-graft healing in the maxillofacial region is generally limited to clinical evaluation, radiographs, and biopsy. A noninvasive quantitative radionuclide method has been developed in an animal model, and it seems to allow earlier prediction of graft failure or success than conventional methods. Using a localization technique to identify preselected regions of interest reproducibly in the graft and adjacent host bone, an activity ration was developed between the graft region and a contralateral control. Two mandibular grafting systems were evaluated with this technique. When the activity ratio for the graft region over the period of study approached, or was greater than, the activity ratio for the host bone, the graft subsequently proved successful by clinical observation and gross dissection. When the activity ratio for the host bone remained greater than that of the graft, healing did not occur and the grafts were unsuccessful. This method allowed prediction of graft fate by 6 wk after grafting, and preceded radiographic confirmation of repair or failure by 2-3 wk.