34th Annual Scientific Meeting proceedings

Objectives:

Diagnosing digital flexor tendon sheath (DFTS) pathologies is often unreliable using ultrasonography and tenography, especially determining lesion laterality can be challenging. Standing DFTS CT-tenography (CTT) may aid in the pre-operative diagnosis of intrathecal soft tissue lesions and in surgical planning. This study aimed at determining the diagnostic performance of ultrasonography and CTT to detect naturally occurring intrathecal tendon lesions in horses undergoing tenoscopy.

Methods:

Twenty horses with a positive DFTS block, inconclusive ultrasonographic examination, tenography, CTT and tenoscopy were included. Images were retrospectively evaluated by a radiologist. For each structure it was recorded whether a lesion was present or not. Sensitivity and specificity were calculated for each modality using tenoscopy as the reference, and values compared amongst modalities (McNemars tests).

Results:

CTT showed a significantly higher overall sensitivity (96%) than ultrasonography (50%) (P=0.0077) for detecting intrathecal tendon lesions. Specificity was not different between CTT (85%) and ultrasonography (85%, P=1).

CTT detected all deep digital flexor tendon lesions (9/9, 100%); ultrasonography detected 4/9 lesions (44%). CTT detected more manica flexoria lesions (8/9, 89%) than ultrasonography (5/9 lesions, 56%). CTT detected all superficial digital flexor tendon lesions (2/2, 100%); ultrasonography (1/2 lesions, 50%).

Conclusions:

CTT showed high sensitivity and specificity values for intrathecal lesion detection, and was more sensitive, but equally specific as ultrasonography. Pre-operative planning was improved by recognition of lesion laterality by CTT. Standing CTT is recommended whenever a definitive diagnosis in DFTS pathology cannot be made using standard imaging modalities.