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Updated: Aug 8, 2026
Non-invasive Imaging of Leukocyte Homing and Migration in vivo
Published on: December 6, 2010
Indium-111-labeled leukocytes for the detection of infection: current status
1Department of Radiology, University of Utah School of Medicine, Salt Lake City 84132.
Insights
Labeled leukocytes demonstrate high sensitivity for detecting infections, including chronic and prosthetic joint infections. Factors like antibiotic therapy and certain medical conditions do not significantly impact scan accuracy, though specificity is reduced in the GI tract and lungs.
Area of Science:
- Nuclear Medicine
- Infectious Disease Imaging
- Immunology
Background:
- Leukocyte labeling with various chelates is a diagnostic tool for infection detection.
- Sensitivity of labeled leukocytes, particularly indium-111 (111In)-labeled cells, varies with imaging time and infection type.
Purpose of the Study:
- To evaluate the diagnostic utility and sensitivity of labeled leukocytes for various infections, including musculoskeletal and chronic infections.
- To assess the impact of factors like antibiotic therapy, hemodialysis, and hyperglycemia on leukocyte scan sensitivity.
Main Methods:
- Review of studies utilizing different chelates for leukocyte labeling and imaging.
- Analysis of sensitivity and specificity data for labeled leukocytes in different anatomical locations and infection types.
Main Results:
- Labeled leukocytes show 90%-95% sensitivity for infection at 24 hours postinjection.
- High sensitivity is observed for infected prostheses and chronic infections (≥2 weeks old).
- Antibiotic therapy and conditions like hemodialysis, hyperglycemia, and steroids do not significantly reduce scan sensitivity, but specificity is low in the GI tract and lungs (10%-50%).
Conclusions:
- Labeled leukocytes are effective for detecting various infections, including challenging cases like infected prostheses and chronic infections.
- Scan sensitivity is generally reliable despite confounding factors, though interpretation requires caution in the gastrointestinal tract and lungs.
Abstract:
Several chelates are available for leukocyte labeling. Studies indicate that cells labeled with any of the chelates have a sensitivity for infection of 90% to 95% when imaged at 24 hours postinjection. The sensitivity of 111In-labeled leukocytes at earlier imaging times is more controversial. There has been concern about the utility of labeled leukocytes in musculoskeletal infection. Recent leukocyte studies show a high sensitivity for infected prostheses, even though these infections are often walled off and do not cause systemic symptoms. However, leukocytes frequently miss osteomyelitis of the spine for reasons that are not known. Although some investigators do not recommend the use of 111In-labeled leukocytes in chronic infections, we have found a high sensitivity for infections that are 2 or more weeks old. Autopsy studies from the preantibiotic era indicate that bacterial infections with common organisms have high levels of neutrophil infiltration for months. Labeled lymphocytes from mixed-cell preparations also may play a role in detecting these inflammatory sites. Questions have been raised about the effect of antibiotic therapy on leukocyte sensitivity. Antibiotics do not appear to have a significant effect on scan sensitivity. By reducing the number of bacteria at an inflammatory site, antibiotics reduce the amount of chemotactic inhibitors. In addition, some antibiotics have been shown to directly stimulate leukocyte chemotaxis. Other factors that can theoretically reduce leukocyte function, including hemodialysis, hyperalimentation, hyperglycemia, and steroids, do not appear to reduce labeled leukocyte sensitivity for infection. The specificity of leukocyte uptake is reduced in the gastrointestinal tract and lungs. In these sites, uptake correlates with infection or the true cause of the patients' fever in only 10% to 50% of cases.
