Abstract

The diagnostic accuracy of scintigraphy performed after injection of indium-111-labeled nonspecific human immunoglobulin G (IgG) was studied in 113 patients with 120 foci of suspected infection in bone (52 chronic and eight acute infections), joints (15 localizations), joint prostheses (37 prostheses), and soft tissue of the locomotor system (eight localizations). All patients also underwent standard three-phase scintigraphy after injection of technetium-99m-labeled methylene diphosphonate. A scan obtained with In-111-labeled IgG was considered positive if focal increasing accumulation was noted over time. In 51 patients (45.1%), the results of scintigraphy were verified with intraoperative cultures, and in 21 patients (18.6%), with needle aspiration. The prevalence of infection was 59%; overall sensitivity, 97%; and specificity, 85%. Use of In-111-labeled IgG enabled correct identification of the presence, site, and extent of infection in 69 of 71 proved foci of infection; 41 of 48 negative studies were correct. Only two infections proved with culture were missed; in both patients, the cultures revealed growth of Staphylococcus aureus in low counts.