In vivo longitudinal assessment of bone resorption in a fibular osteotomy model using micro-computed tomography.

Longitudinal in vivo micro-computerized tomography (CT) imaging was used to monitor bone resorption in a rat fibula osteotomy model. Quantitative image post-processing techniques were developed for spatially aligning the longitudinal data sets. Nominal length and bone volume in the proximal and distal segments of the fibula after the osteotomy were measured, and quantitative comparisons of bone loss over a 13-week period post-surgery were made in five individual rats. A significant decrease in nominal length and bone volume of the distal segment was observed 13 weeks post surgery. A significant decrease in bone volume was also observed in the proximal segment. However, no change in nominal length was observed for the proximal segment of the fibula. This study illustrates the power of this non-invasive technology to measure in vivo small changes in bone length and volume using just a small cohort of animals.