Magnetic resonance arthrography of the cubital joint in dogs affected withfragmented medial coronoid processes

Objective-To evaluate efficacy of intra-articular injection of gadolinium t etra- azacyclododecane tetraacetic acid (gadolinium-DOTA) for delineating f ragmented medial coronoid processes (FMCP) and lesions on the medial aspect of the humeral condyle (MAHC). Sample Population-14 cubital joints in 9 dogs. Procedure-Magnetic resonance imaging (MRI) was performed with and without i ntra-articular injection of a solution of 2 mmol of gadolinium-DOTA/L. Arth rographic images obtained after injection of contrast medium were compared with those obtained without contrast medium. Evidence of contrast medium ar ound or in the medial coronoid process and infiltration of contrast medium in subchondral bone lesions was recorded, Twenty-four hours after imaging, arthroscopy was performed, and lesions detected were correlated with result s of MRI. Results-An abnormal coronoid process was diagnosed in 13 of 14 joints. A fr agmented process (free) was seen in 7 of 14 joints; nondisplaced mineralize d medial tin situ) coronoid processes were evident in 4 joints; and nondisp laced unmineralized medial coronoid processes were evident in 2 joints. Les ions on the MAHC were diagnosed in 4 of 12 joints. In 5 joints, a hyperinte nse signal resulted from contrast medium that infiltrated between the fragm ented process and ulna. In 2 joints, contrast medium did not infiltrate com pletely around the process and was stopped by an isointense structure tie, abnormal cartilage). Subchondral bone lesions were enhanced by use of contr ast medium. Conclusion and Clinical Relevance-Use of arthrography enabled us to identif y FMCP easily, but did not provide important additional information about c hanges on the medial coronoid process, compared with MRI performed without contrast medium.