Are We Missing Elbow Pathology in Dogs? What Contrast-Enhanced CT Reveals

Diagnostic value of contrast-enhanced CT for elbow joint disorders in dogs

Bettina Rohr; Sven Reese; Martin Zöllner; Andrea Meyer-Lindenberg

Background

Elbow joint disorders are a frequent cause of forelimb lameness in dogs and commonly include conditions within the elbow dysplasia complex as well as flexor enthesopathy and humeral intracondylar fissure. While computed tomography (CT) is widely used for diagnosing osseous elbow pathology, the additional diagnostic value of intravenous contrast agents in canine elbow CT has not previously been systematically evaluated. The study aimed to determine whether contrast-enhanced CT provides clinically relevant information beyond unenhanced imaging, particularly for soft tissue involvement.

Methods

This retrospective study evaluated 326 elbow joints from 163 dogs with unilateral or bilateral lameness attributed to elbow pathology. All dogs underwent radiography and CT of both elbows, including unenhanced and contrast-enhanced CT imaging. Primary diseases and periarticular osteophytes were assessed using radiographs and unenhanced CT in the bone window. Post-contrast CT images were evaluated in the soft tissue window for enhancement of the joint capsule and flexor muscles. Elbow joints without pathology, lameness, or enhancement served as controls. Statistical analyses examined associations between specific diagnoses and contrast enhancement patterns.

Results

Contrast enhancement was identified in 137 of 326 elbow joints (44.9%). Enhancement was limited to the joint capsule in 68.6% of cases, to the flexor muscles in 11.7%, and involved both structures in 19.7%. Joint capsule enhancement was most strongly associated with periarticular osteophytes and was also correlated with medial coronoid process disease and ununited anconeal process. Flexor muscle enhancement showed the strongest association with epicondylar spurs and caudal calcified bodies, but not medial calcified bodies. Notably, 14 elbow joints showed flexor muscle enhancement without any bony indicators of flexor enthesopathy, findings that were detectable only with contrast-enhanced CT.

Limitations

The study was retrospective in design and some disease combinations were represented by small case numbers, limiting statistical power for certain comparisons. Arthroscopic confirmation was not available for all elbow joints. Additionally, adverse effects of contrast agents may have been underreported due to incomplete retrospective documentation.

Conclusions

Contrast-enhanced CT did not improve detection of primary osseous elbow diseases such as medial coronoid process disease, osteochondrosis dissecans, ununited anconeal process, or humeral intracondylar fissure. However, it provided valuable information on active inflammation, synovitis, and flexor enthesopathy, including early or concomitant soft tissue disease not visible on radiographs or unenhanced CT. The authors conclude that contrast administration during elbow CT can help avoid overlooked pathology, particularly flexor enthesopathy, but should be considered on a case-by-case basis, balancing diagnostic benefit against potential risks.

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