Imaging techniques for evaluation of postoperative orthopedic infections

Labeled leukocyte scintigraphy is the preferred imaging technique for the evaluation of suspected postoperative orthopedic infections. Labeled leukocyte localization returns to a normal pattern faster than MRI after bone trauma, surgical procedures, and treatment of osteomyelitis. 99mTc HMPAO labeled leukocyte scintigraphy is useful, particularly in children, because less peripheral blood volume is required for labeling. However, delayed 16-20 hour imaging is usually needed to detect low-grade osteomyelitis, and 111In WBC usually provides better images in adults. Combined 111In WBC/99mTc sulfur colloid marrow images improve the specificity for detection of osteomyelitis in regions containing active bone marrow. Simultaneous 111In leukocyte/99mTc bone SPECT imaging is usually necessary in regions such as the skull, spine, and hips, where there is overlapping bone, and soft tissues.