Figure 2.

depicts color T₂ maps (beneath which is the reference gray scale image generated from the shortest echo image of the T₂ mapping sequence) obtained in vivo in a 3T MR scanner in the coronal plane 9 weeks after vascular interruption surgery in three goats (Panels A–D). Panel A demonstrates normal epiphyseal cartilage of the medial femoral condyle in the left unoperated (control) limb of goat 4. Red ovals mark areas of increased relaxation time, consistent with ischemic cartilage necrosis, and delay of the progression of the ossification front (Panel D) in the operated right medial femoral condyle of goats 4, 3, and 2 (Panels B, C and D). Increased relaxation time and delayed progression of the ossification front in the area of ischemic cartilage necrosis (marked with red oval) are apparent in the T₂ map obtained at 9.4T ex vivo in goat 2 (Panel E). An area of ischemic chondronecrosis, characterized by pallor of the matrix is present in a safranin O stained histological section of the operated right medial femoral condyle of goat 2, and is accompanied by focal delay in the progression of the ossification front (red arrowheads, Panel F). Hematoxylin and eosin stained section at 40 × (inset) showing the interface of necrotic (above dotted line) and viable (below dotted line) epiphyseal cartilage from the area identified with the black rectangle in panel F. Black arrows indicate the surgical scars (Panels B–F).