Comparison of MRI and pathology of periosteal change in experimental bone tumor

Objective: To study MRI features and pathologic basis of various periosteal changes in rabbit VX₂ bone tumor and to evaluate the role of MRI in the change of periosteum in bone tumor. Methods: Bone tumor models were induced by injection of VX₂ carcinoma cell suspension into the medullary cavity of right tibias in 32 rabbits. Thirty-six positive contrast cases and 4 negative contrast cases were established. Serial plain films and MRI examinations were performed at an interval of 5 days following the implantation. Every 4 rabbits were sacrificed immediately after imaging. The findings of periosteal changes were compared between imaging features and pathologic results. Results: From the 5th to 15th day after implantation of VX₂ carcinoma, periosteal edema was demonstrated in 32 tibias. On the 20th day, periosteal thickening was revealed in 19 tibias. On the 25th day, periosteal new bone with the thickened periosteum attaching to its outer surface was found in 12 tibias. On the 30th day, periosteal new bone with the thickened periosteum were elevated by the tumor in 11 tibias. On the 35th to 40th day, destruction of periosteal bone and periosteum were revealed. Conclusions: The progress of periosteal changes in rabbit VX₂ bone tumor included periosteal edema, periosteal thickening, periosteal new bone, destruction of periosteal new bone and destruction of periosteum. Various periosteal changes could be demonstrated on MRI and MRI is useful in evaluating periosteal changes.