Comparison of indium-111 nonspecific polyclonal IgG with indium-111-leukocytes in a canine osteomyelitis model.

Osteomyelitis was surgically produced in the proximal tibia of ten dogs. A sham operation was performed on the other tibia. Early (3 hr) and late (20 hr) imaging was performed 1, 4, 7, 10, and 13 wk later, while the osteomyelitis progressed from acute to chronic. Indium-111-IgG had a significantly greater accumulation at the osteomyelitis site than 111In-leukocytes, both during early (p = 0.001) and late (p = 0.03) imaging, and at each of the weeks studied (p less than 0.001). During early imaging, both agents gave equivalent lesion to background ratios. On the late images, the 111In-leukocytes gave significantly higher lesion-to-background ratios than 111In-IgG (p less than 0.001) and higher ratios than they did during the early images (p less than 0.001). Both agents had greater accumulation in acute osteomyelitis than in chronic osteomyelitis (p less than 0.02). Osteomyelitis in the surgical site can be distinguished from the uptake in the sham surgery site using 111In-leukocytes, but not when using 111In-IgG.