MAGNETIC-RESONANCE-IMAGING OF MASSIVE BONE ALLOGRAFTS WITH HISTOLOGICCORRELATION

Objective. The objective of this study was to better understand the MR I appearance of massive bone allografts. Design. The MRI findings of t hree massive bone allografts imaged in vivo were correlated with the h istologic findings following removal of the allografts. A fourth allog raft, never implanted, was imaged and evaluated histologically. Patien ts. Allografts were placed for the treatment of primary or recurrent o steosarcoma. Results and conclusions. The in-vivo allografts have a he terogeneous appearance on MRI which we attribute to the revascularizat ion process. Fibrovascular connective tissue grows into the graft in a patchy, focal fashion, down the medullary canal from the graft-host j unction and adjacent to the periosteum. The marrow spaces are initiall y devoid of normal cellular elements and occupied by fat and gelatinou s material. This normal postoperative appearance of massive bone allog rafts must not be interpreted as recurrent neoplasm or infection in th e allograft. Recognition of these complications rests on features outs ide the marrow.