A comparison of micro-CT, microradiography and histomorphometry in bone research

Abstract

Objective Intraobserver reliability and agreement were determined for microradiography (MR), micro-computed tomography (μCT) and histomorphometry (HM). These three modalities were compared for quantitative measurements of bone formation and graft modelling in rat mandibular defects and grafts. Design Twelve rats were randomly selected from a larger experiment, evaluating bone formation in rat mandibular defects and bone modelling in grafts. Twelve lateral microradiographs were taken of the grafts. μCT images were obtained from all defects and grafts (24 specimens). Defects and grafts were cut perpendicularly through their centre. Microradiographs, μCT images and histological sections were obtained from the resulting 48 specimens. New bone volume and graft volume were measured using image analysis software on MR and μCT images. Defect width and graft width were measured using images from HM, MR and μCT. The results were compared to each other. Results The intraobserver reliabilities for the measurements of new bone volume by μCT, and the measurement of graft modelling by MR and graft volume by μCT were high. The differences between MR, HM and μCT were larger in defect width measurements than in graft width measurement. MR measured smaller defects than HM and μCT. The 95% confidence interval was larger in defect width measurements compared to graft width measurements. Conclusions The methods of MR and μCT image analysis are reliable but preferably should be used in combination as to obtain valid conclusions. HM, MR and μCT for graft widths measurements showed more agreement than for defect width measurements. MR appears to overestimate bone formation.