From the Guidelines
Contrast is not always necessary to visualize osteomyelitis, as fluid-sensitive sequences alone may be sufficient for diagnosis, with one study noting 100% identification of cases of septic arthritis and osteomyelitis in children. However, the use of contrast agents, such as gadolinium-based agents, can improve the detection of abscesses and help differentiate osteomyelitis from other conditions like Ewing sarcoma 1.
When evaluating for osteomyelitis, MRI is widely regarded as sensitive and specific, with sensitivity reportedly 82% to 100% and specificity 75% to 96% 1. The use of fat-suppressed T1-weighted imaging and the presence of subperiosteal fluid can be useful in diagnosing osteomyelitis, especially in challenging scenarios like differentiating it from Ewing sarcoma or marrow infarction in children with sickle cell disease 1.
Some key points to consider when diagnosing osteomyelitis include:
- MRI is the gold standard for diagnosing osteomyelitis, with or without contrast agents
- Fluid-sensitive sequences alone may be sufficient for diagnosis in some cases
- Contrast agents can improve the detection of abscesses and help differentiate osteomyelitis from other conditions
- Subperiosteal fluid and fat-suppressed T1-weighted imaging can be useful in diagnosing osteomyelitis
- Repeat MRI may be necessary for worsening or persistent symptoms, resulting in clinical management changes in some patients 1.
In terms of morbidity, mortality, and quality of life, the use of contrast agents should be carefully considered, as they can improve diagnostic accuracy and help guide treatment decisions, but may not be necessary in all cases. Ultimately, the decision to use contrast agents should be made on a case-by-case basis, taking into account the individual patient's needs and circumstances 1.
From the Research
Diagnostic Methods for Osteomyelitis
- Radiography is considered the first-line screening exam for clinically suspected osteomyelitis, but additional evaluation is generally needed 2
- MRI is the definitive diagnostic exam with high sensitivity and specificity combined with excellent anatomic definition, and can be used with or without contrast 2, 3
- Gadolinium contrast can be useful to detect areas of devitalization before surgery, but evidence suggests that it may not be necessary for routine cases of suspected non-spinal osteomyelitis 3, 4
Use of Contrast in MRI for Osteomyelitis
- A systematic review found that MRI with gadolinium-based contrast has 89% sensitivity, 79% specificity, and 90% overall diagnostic accuracy for diagnosing osteomyelitis in the appendicular skeleton 3
- The same review found that MRI without gadolinium-based contrast has 92% sensitivity, 89% specificity, and 96% overall diagnostic accuracy for diagnosing osteomyelitis in the appendicular skeleton 3
- Another study found that fat-suppressed contrast-enhanced MR imaging has a sensitivity of 88% and specificity of 93% in diagnosing osteomyelitis, and is particularly useful in patients with complicating clinical factors 4
Alternative Contrast Agents
- Ferumoxytol, a superparamagnetic iron oxide nanoparticle preparation, has been shown to be a promising approach for diagnosing osteomyelitis, with MRI contrast changes correlating with systemic markers of inflammation 5
- Ferumoxytol-induced MRI contrast changes have been compared with those observed using standard-of-care Gadolinium, with promising results 5
Other Imaging Modalities
- Conventional radiography should always be the first imaging modality, but may not be sufficient for diagnosing osteomyelitis 6
- Nuclear medicine and MRI are the most sensitive and most specific imaging modalities for the detection of osteomyelitis, with nuclear medicine being particularly useful in identifying multifocal involvement 6