Cartilage defect identification on computed tomography arthrography in equine fetlock: Ex-vivo study.

The research study in this article aimed at finding out the minimum volume of iodinated contrast medium (CM) required for Computed Tomography Arthrography (CTA) to visibly identify man-made cartilage defects in horse fetlock. It was found that 20 millilitres of CM were required to visualize 100% of the defects, irrespective of their location.

Study Design and Procedure

• Using 32 distal limbs from adult horses, which were collected at the time of slaughter, an ex-vivo study was conducted.
• At 5 predetermined areas on the horse fetlock, iatrogenic (human caused) cartilage defects were created using an arthroscope.
• Each fetlock then underwent a total of 10 CT scans, starting with a pre-contrast scan, followed by scans with progressively increasing volumes of CM, ranging from 2.5 ml to 40 ml.
• After the completion of the scans, the cartilage defects were then manually measured using a calliper.

Data Collection and Analysis

• All the CTA scans were evaluated by a single operator, who checked for the presence/absence of defects and also measured their volume.
• Data from the study were expressed as median and interquartile cell population values.
• A Chi-square test was used to examine the association between the scan assessments and the varying CM volumes used.
• Correlation between the measurements from the CT scans and manual (macroscopic) assessments were evaluated using Spearman’s coefficient.
• Statistical significance was defined as a p-value less than 0.05.

Key Findings

• It was determined that a contrast medium volume of 20 ml was required to visualize all the cartilage defects, irrespective of where they were located on the fetlock.
• The study found a weak correlation between the volumes of defects measured macroscopically and those assessed on the CT scan.
• This suggests that while 20 ml CM is sufficient to identify the presence of a cartilage defect, it may not be fully accurate for determining the defect’s volume.
• Thus, the research supports the conscious use of iodinated CM, tailored to specific diagnostic needs.