MRI in spondyloarthritis: when and how?

Area of Science:

• Rheumatology
• Radiology
• Medical Imaging

Background:

• Axial spondyloarthritis (SpA) diagnosis relies on imaging, with sacroiliac joint (SIJ) involvement being key.
• Early detection of axial SpA is crucial for timely intervention and management.
• Magnetic resonance imaging (MRI) offers detailed visualization of SIJ pathology.

Purpose of the Study:

• To review recent advancements in using MRI for early recognition of axial SpA.
• To highlight the challenges and potential of MRI in diagnosing axial SpA.
• To discuss the role of MRI in conjunction with other imaging modalities.

Main Methods:

• Review of current literature on MRI techniques for axial SpA.
• Analysis of the diagnostic utility of bone marrow edema (BME) and structural lesions on SIJ MRI.
• Comparison of MRI findings with other imaging modalities like low-dose computed tomography and pelvic radiographs.

Main Results:

• Low-grade BME on SIJ MRI can be nonspecific; combining it with structural lesions enhances diagnostic specificity for axial SpA.
• Structural lesions identified on MRI show high concordance with low-dose computed tomography, validating SIJ MRI's criterion validity.
• Accumulating evidence suggests SIJ MRI may replace traditional pelvic radiographs where MRI is accessible, due to superior reliability of structural lesion assessment.

Conclusions:

• SIJ MRI evaluation should integrate both structural lesions and BME for accurate diagnosis of axial SpA.
• MRI is a valuable component of pattern recognition for diagnosing SpA, but not the sole determinant.
• Disseminating imaging advancements in SpA to rheumatologists and radiologists remains an unmet need.