Repeatability of diagnostic ultrasonography in the assessment of the equine superficial digital flexor tendon.

This research investigates the variability in ultrasonography of the equine superficial digital flexor tendons, using tendon cross-sectional area (CSA) measurements as a comparative variable. It found no significant differences when different operators performed the image acquisition or used different equipment in the analysis. However, differences were found when different operators undertook the image analysis and the study concludes to minimize variability, a single operator should handle the image analysis.

Objective

The main focus of this research was to quantitatively assess the variability that can occur during the ultrasonographic examination of the equine superficial digital flexor tendons (SDFT). The researchers aimed to use an objective measure – CSA, or cross-sectional area – to quantify any discrepancies.

Method

The experiment involved three variables being introduced to measure their effects on the CSA measurements:

• Image acquisition operator (IAc): This involved two different operators performing the ultrasonographic examination;
• Image analysis operator (IAn): This also used two different operators, but this time for the task of calculating CSA values from pre-existing images; and
• Analytical Equipment (IEq): Two different sets of equipment were used during the CSA calculation stage.

Procedure

The experiment involved two operators acquiring transverse ultrasonographic images from the forelimb SDFTs of 16 National Hunt Thoroughbred racehorses. Each operator also took charge of analyzing their own and each other’s images. For one operator, the analysis was undertaken using two different sets of equipment.

Findings

No significant difference was revealed, statistically speaking, when different operators handled the task of image acquisition (P>0.05) or when different equipment was used during the analysis, except at the most distal level (P>0.05). However, one key finding was a statistically significant difference when different operators undertook image analysis (P<0.01) – one operator consistently produced larger measurements.

The research concluded that having different operators conduct different stages of an examination may result in substantial variability.

Recommendations

To reduce potential inconsistency during ultrasonographic studies involving multiple operators, the study suggests that one operator should undertake the entire process of image analysis. The image acquisition stage, however, can be assigned to different operators without affecting the accuracy of the result.