Comparison of Bone Mineral Content of the Equine Third Metacarpal to Total Radiographic Bone Aluminum Equivalents From Unprocessed Digital Radiographs.

The research article evaluates the efficacy of using digital radiographs for estimating Bone Mineral Content (BMC) in horses, by comparing the radiographic bone aluminum equivalents (RBAE) derived from digital radiographs to BMC obtained from bone ash, and physical and digital measurements of the bone. The study finds that while digital radiographs can accurately measure morphological parameters and estimate BMC, it underlines the importance of using unprocessed radiographs to avoid distortion of RBAE.

Research Methodology

• The researchers conducted digital radiography on six third metacarpals (MCIII) extracted from horse cadavers, using an aluminum step wedge penetrometer. This aids in creating a comparative standard for the radiographs.
• A segment of bone, approximately 2 cm wide, was digitally examined and extracted from each MCIII.
• A linear regression was computed using the varying thicknesses of the step wedge, a procedure that displayed high correlation (R > 0.99).
• This linear regression was employed to calculate total and individual RBAE.
• Physical and digital measurements of both diameter and cortical thickness were recorded on dorsal-palmar (DP) and lateral-medial (LM) aspects of the bone.
• The bone samples were then put through a processing cycle of ether extraction, oven drying, and ashing to obtain the BMC.

Key Findings

• Physical and digital measurements of the dorsal, medial, and lateral cortices, as well as the DP outer diameter, demonstrated similarity (r > 0.74, P < .09), implying a high accuracy of digital measurements. However, the palmar cortical measurements did not show any strong correlation (r = 0.41, P = .42).
• The LM outer and DP/LM inner diameter measurements were also similar between the two methods, thus further confirming the accuracy of digital measurements (r > 0.95, P < .05).
• A strong correlation between total RBAE and BMC (r > 0.93, P < .01) was observed, suggesting that the use of digital radiographs is reliable for calculating BMC in equine studies.
• Despite the overall accuracy of the digital radiographs for estimating BMC and making morphological measurements, the study emphasizes the need to use unprocessed radiographs to prevent any distortion in RBAE.