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Complicated bone and soft-tissue infections. Imaging with 0.1 T MR and 99mTc-HMPAO-labeled leukocytes. ff
1Department of Radiology, University Central Hospital, Helsinki, Finland.
Purpose:
To assess the value of imaging by 0.1 T MR and by 99mTc-HMPAO-labeled leukocytes in confirming skeletal infection in patients with soft-tissue infections and/or bone pathology.
Methods:
Thirty-nine anatomical sites (35 patients) with suspected bone infection were prospectively imaged with 0.1 T MR and 99mTc-HMPAO-labeled leukocytes. Thirty-two infected areas were confirmed: 12 osteomyelitis (out of which 3 were spondylitis) and 27 soft-tissue infections (both bone and soft-tissue infection in 7 areas).
Results:
MR imaging showed 31 true-positive, 3 true-negative, 4 false-positive and one false-negative diagnosis of infection and scintigraphy 27, 7, 0 and 5 respectively. The sensitivity of MR for osteomyelitis was 100% (12/12) and of scintigraphy 42% (5/12), p<0.01. The specificity of MR and of scintigraphy for osteomyelitis were 81% (22/27) and 93% (25/27) respectively. The sensitivity of MR for soft-tissue infection was 96% (26/27) and specificity 75% (9/12). The correspoding figures for scintigraphy were 85% (23/27) and 100% (12/12). MR and scintigraphy were concordant with respect to the final diagnosis in 28/39 (72%) sites and discordant in 10 (26%). In one patient with Charcot osteoarthropathy a false-positive finding was found by both methods. MR detected all 3 cases of spondylitis, scintigraphy none. Nonpyogenic inflammations and neuroarthropathic joints were indistinguishable from infection by MR.
Conclusion:
Combined imaging with MR and 99mTc-labeled leukocytes is recommended in diagnostically complicated bone infections except for spondylitis where MR is the method of choice. Congruent positive findings are highly suggestive of infection, the extent of which can be determined. Congruent negative results exclude infection.
Insights
Magnetic resonance (MR) imaging and technetium-99m-labeled leukocytes are valuable for diagnosing bone infections. MR is particularly effective for spondylitis, while combined imaging aids in complex cases.
Area of Science:
- Medical Imaging
- Nuclear Medicine
- Orthopedics
Background:
- Skeletal infections require accurate diagnostic methods.
- Differentiating infection from other pathologies can be challenging.
- Evaluating imaging modalities is crucial for patient management.
Purpose of the Study:
- To compare the diagnostic value of 0.1 T MR imaging and 99mTc-HMPAO-labeled leukocyte scintigraphy.
- To assess their efficacy in confirming skeletal infections in patients with soft-tissue infections or bone pathology.
Main Methods:
- Prospective imaging of 39 anatomical sites in 35 patients with suspected bone infection.
- Utilized both 0.1 T MR imaging and 99mTc-HMPAO-labeled leukocyte scintigraphy.
- Correlated imaging findings with confirmed diagnoses.
Main Results:
- MR imaging demonstrated higher sensitivity for osteomyelitis (100%) and soft-tissue infection (96%) compared to scintigraphy.
- Scintigraphy showed higher specificity for soft-tissue infection (100%) than MR (75%).
- MR successfully identified all spondylitis cases, while scintigraphy identified none. Concordance between methods was 72%.
Conclusions:
- Combined MR and 99mTc-labeled leukocyte imaging is recommended for complex bone infections.
- MR imaging is the preferred method for diagnosing spondylitis.
- Concordant positive findings strongly suggest infection; congruent negative results exclude it.