Quantification of Massive Allograft Healing with Dynamic Contrast Enhanced-MRI and Cone Beam-CT: A Pilot Study

Nicole Ehrhart VMD, MS, Susan Kraft DVM, PhD, David Conover MS, Randy N. Rosier MD, PhD, Edward M. Schwarz PhD
Symposium: New Approaches to Allograft Transplantation
Volume 466, Issue 8 / August , 2008

Abstract

Although massive allografts are widely used for reconstruction of critical defects in long bones caused by tumor or trauma, many will have inadequate long-term outcomes. Toward a tissue engineering solution to this problem, we developed experimental stem cell and gene therapy adjuvants that induce angiogenesis, osteogenesis, and remodeling of the structural allografts. We present data from pilot studies to show the utility of dynamic contrast enhanced MRI (DCE-MRI) to quantify vascularity after femoral osteotomy in a canine femur model and cone beam CT (CB-CT) to quantify bone volume in a patient after composite prosthetic-allograft reconstructive surgery. The results demonstrate our ability to suppress the artifacts generated by the metal implants required to secure massive allografts such that precise quantification of cortical bone revascularization (>10-fold increase at 3 weeks postoperatively) and new bone formation (accurate to about 193 μm3) around the graft can be performed longitudinally via DCE-MRI and CB-CT, respectively.