Comparison of mean bone densities of three preparations of the distal portion of the equine third metacarpal bone measured by use of quantitative computed tomography.

This research study examines how the process of cutting specific areas in a horse’s subchondral bone may influence the calculation of bone density when using quantitative computed tomography (QCT). The findings indicate that slicing the bone to define regions of interest results in a substantial decrease in mean bone density, potentially leading to inaccurate modeling and diagnosis of joint conditions via CT imaging.

Objective of the research

• The primary objective of this study was to determine whether the procedure of sectioning a horse’s subchondral bone to identify specific regions of interest has significant influence on the averaged bone density calculation when using Quantitative Computed Tomography (QCT).

Research Methodology

• Two metacarpophalangeal joints from equine cadavers were used as samples for this study.
• The distal part of each joint’s third metacarpal bone was analyzed with CT scanning to replicate real-life conditions.
• The metacarpophalangeal joints were then disassembled and dissected, after which they underwent air-based CT scanning.
• Six 1-cm² regions of interest (ROIs) were surgically sliced into the distal condylar surfaces to depths of roughly 1 cm, followed by another round of CT scanning.
• Using data from each array of scan images, the researchers developed three-dimensional CT models for each third metacarpal bone.
• The densities of the six ROIs were then measured and compared among intact, dissected, and sectioned third metacarpal bone scans.

Findings of the research

• The mean bone density was significantly lower in sectioned bone preparations, compared to intact or dissected bones.
• No notable variation was found between the mean bone densities for the intact and dissected bone preparations.

Conclusions

• The research concludes that the process of cutting subchondral bone to delineate specific ROIs before conducting CT imaging was found to significantly lower the mean bone density as calculated with QCT, hence creating substantial artifacts.
• This has direct implications for the way CT modelling is done for the equine subchondral bone in diagnosing joint diseases in horses. Incorrect bone density measurements could lead to misdiagnosis or misunderstanding of disease severity.