Comparison of radiography, magnetic resonance imaging, and surgical findings in dogs with elbow dysplasia

Objective-To describe the magnetic resonance imaging (MRI) appearance of medial coronoid process and humeral condyle lesions in dysplastic cubital joints and to compare survey radiography and MRI for evaluation of fragmented medial coronoid process (FMCP) and lesions of the medial aspect of the humeral condyle (MAHC). Animals-18 dogs with elbow dysplasia. Procedure-Radiography of 22 cubital joints was performed. The 22 joints then underwent MRI. The scans were evaluated with regard to the shape and signal of the coronoid process; articular cartilage change, subchondral bone disruption of the MAHC. Surgical findings were used as the standard to calculate accuracy, sensitivity, specificity, and positive-and negative-predictive values for specific diagnosis of FMCP (free fragment) and lesions of the MAHC. Results-At surgery, 31.8% of the joints had FMCP (free), 36.4% had nondisplaced unmineralized coronoid process, and 27.2% had nondisplaced mineralized coronoid process, Eleven joints had lesions of the MAHC, and wear lesions were observed in 41% of the joints. On radiography, FMCP (free) was visualized in 9% of the joints and lesions of the MAHC were observed in 23%. MRI had the highest accuracy (95.5%), sensitivity (100%), and negative-predictive value (100%) for detection of FMCP (free), and had accuracy (91%), sensitivity (87.5%), specificity (92.5%), and positive (87.5%)- and negative (92.5%)- predictive values for detection of nondisplaced unmineralized coronoid process. Conclusions and Clinical relevance-Compared with radiography, MRI was useful for detection of nondisplaced unmineralized coronoid process; images consistently correlated with surgical findings. The technique is accurate and especially useful when radiographic findings are inconclusive.