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

OBJECTIVE

Intraobserver reliability and agreement were determined for microradiography (MR), micro-computed tomography (microCT) 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. microCT images were obtained from all defects and grafts (24 specimens). Defects and grafts were cut perpendicularly through their centre. Microradiographs, microCT 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 microCT images. Defect width and graft width were measured using images from HM, MR and microCT. The results were compared to each other.

RESULTS

The intraobserver reliabilities for the measurements of new bone volume by microCT, and the measurement of graft modelling by MR and graft volume by microCT were high. The differences between MR, HM and microCT were larger in defect width measurements than in graft width measurement. MR measured smaller defects than HM and microCT. The 95% confidence interval was larger in defect width measurements compared to graft width measurements.

CONCLUSIONS

The methods of MR and microCT image analysis are reliable but preferably should be used in combination as to obtain valid conclusions. HM, MR and microCT for graft widths measurements showed more agreement than for defect width measurements. MR appears to overestimate bone formation.