FIGURE 1.

OCL lesion at the distal humerus of a 4-week-old pig. (A) A hyperintense region within the cartilage in the 3D DESS image (indicated by white arrow) that corresponds to (B) an area with increased T2 values (orange and yellow) within the articular epiphyseal cartilage complex (black arrow) in the T2 map with (C) corresponding histological section showing associated region of chondrocyte necrosis with matrix pallor (outlined in black), consistent with an OCL lesion in the distal humerus of a 4-week-old pig. White clefts between the cartilage (purple) and marrow and bone of the epiphysis and metaphysis are artifactual. H&E, 0.5× magnification. (D) Corresponding T1ρ map with increased T1ρ values in the OCL lesion (black arrow). (E) Higher magnification image (20×) showing localized area of chondronecrosis centrally (bordered by dotted lines) characterized by matrix pallor and chondrocytes that are pyknotic and eosinophilic with loss of detail (chondrocyte cell death). H&E, 10× magnification; scale bar = 100 μm. (F) High magnification image (40×) of the area indicated by the box bordered by dashed lines in (E) demonstrating necrotic chondrocytes (black arrowheads) with diffuse eosinophilia and condensed morphology as compared to unaffected neighboring chondrocytes (lower left). H&E, 40× magnification; scale bar = 20 μm. H&E, hematoxylin & eosin; OCL, osteochondrosis latens.