MAGNETIC RESONANCE IMAGING FEATURES OF CANINE INCOMPLETE HUMERAL CONDYLE OSSIFICATION

Incomplete ossification of the humeral condyle ( IOHC ) is characterized by an intracondylar fissure located where the intercondylar physis is present in growing dogs. Its radiologic and computed tomographic features have been described but the magnetic resonance ( MR ) features have not been characterized. Our purpose was to further describe the range of MR appearances of IOHC , to assess the diagnostic capability of MR relative to radiology, and to determine whether MR is able to identify the disease before a fissure forms. Thirty‐eight elbow MR scans and radiographs, when available, were reviewed and divided into three groups. In Group 1 (affected elbows, n = 22), there was an intracondylar defect on MR with variable appearance; the defect was not visible radiographically in 32% of the elbows. The main difference between Group 2 (nonaffected elbows, n = 6) and Group 3 (contralaterals to IOHC or to condylar fracture, without fissure, n = 10) was the appearance of the humeral condyle in short tau inversion recovery (STIR) sequences: all elbows in Group 2 had a homogeneous humeral condyle, whereas all but one in Group 3 were heterogeneous. One dog in Group 3 developed a complete condylar fissure 7 months after the first examination, when no evidence of an intracondylar defect had been detected. The MR appearance of IOHC is variable and a heterogeneous humeral condyle in STIR images without a clear defect may warn of the possibility for the subsequent development of a condylar fissure.