Contrast-enhanced computed tomographic evaluation of the deep digital flexor tendon in the equine foot compared to macroscopic and histological findings in 23 limbs.

The study reveals the effectiveness of Contrast-enhanced computed tomography (CECT) in identifying and diagnosing distal deep digital flexor tendinopathy, a common cause of foot lameness in horses. The research highlights that CECT, despite a few inaccuracies, has a high sensitivity and could be a worthy alternative to the more common, yet costly and less practical, MRI scan.

About the Study

• The research was a descriptive analysis of computed tomography (CT), macroscopic, and histological findings of the deep digital flexor tendon (DDFT) in horses.
• Both plain and contrast-enhanced CT scans were obtained from 23 limbs of 16 horses diagnosed with clinical lameness localized to the foot.
• All these horses had detectable DDFT lesions that were classified according to their anatomical location and extent using both CT and CECT.
• Postmortem examinations were conducted on all horses, and any gross abnormalities were noted. Tissue samples from the DDFT (both lesion and non-lesion sites) were collected for histological evaluation.
• The outcomes of macroscopic and histological evaluations were later matched with the findings of the CECT scans.

Findings of the Study

• The study identified 67 sites across 23 DDFTs for evaluation. Using CECT imaging, the researchers discovered lesions in 42 sites across 18 tendons.
• The same 42 sites also revealed lesions under macroscopic evaluation, confirming the diagnostic effectiveness of CECT imaging.
• However, there were a few inconsistencies, with 3 false negative and 3 false positive results identified on CECT. This implies that CECT scans mistakenly identified some healthy sites as having lesions and vice versa.
• Despite these few errors, the overall sensitivity of CECT for diagnosing DDFT lesions was found to be as high as 93%, indicating that it was able to correctly identify the vast majority of actual lesions.

Implications of the Study

• The study concluded that CECT, despite its occasional inaccuracies, can be a highly effective supplementary method for diagnosing causes of equine foot pain.
• While magnetic resonance imaging (MRI) remains the gold standard for identifying DDFT lesions, its practical disadvantages and high cost make CECT a promising alternative, especially in cases where MRI is not an option.