PURPOSE: We compared the sequential characteristic MR findings with histopathologic findings in experimentally induced osteomyelitis of rabbits tibiae . MATERIALS AND METHODS: We induced osteomyelitis in the left tibiae of 25 rabbits by direct inoculation of E. coli. Right tibiae of the same rabbits were directly punctured with sterile needle, which were used as control groups. Spin-echo sagittal T1- and T2-weighted images(T1WI & T2WI) and gadolinium-enhanced T1-weighted sagittal images of both tibiae were obtained at 3 days, 5 days, 1 week, 2 weeks, and 4 weeks following inoculation of pathogen. MR-pathologic correlation study was done with emphasis on changes of the morphology and the MR signal intensity(SI) of marrow abscess. RESULTS: Well-defined abscesses were seen on MR 3 -5 days after pathogen inoculation and they all showed low SI on both T1 & T2WI and no enhancement. MR imaging of abscess wall, which became visible at 3 days as high SI on T1WI, gradually changed to low SI on T1WI and high SI on T2WI with diffuse enhancement according to the time sequence (17% after 3 days; 40% after 5 days; 46% after 1 week; 56% after 2 weeks; 60% after 4 weeks). The peripheral portion of the abscess, which was seen in some cases (48% after 3 days; 40% after 4 weeks), showed iso-intensity to muscle on T1WI and ill-defined high SI on T2WI with mild Gd-enhancement. Pathologically the abscesses and their walls were composed of cell debris and granulation tissue with infiltration of inflammatory cells. Fibroblasts and acute inflammatory cells in the abscess wall, which were most prominent at 3 and 5 days relatively, decreased gradually along with the development of abscess. Inner layer of the abscess wall was composed of chronic inflammatory cells, which appeared after 2 weeks of inoculation. The granulation tissue and inner chronic inflammatory cell layer became more organized feature after 4 weeks. The peripheral portion of the abscess revealed as granulation tissue. In the control group, necrosis or inflammatory cell infiltration was absent and the lesion decreased in size to remain only focal fatty change of bone marrow after 4 weeks. CONCLUSION: Central abscess composed of cell debris showed low SI on both T1