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ESR Essentials: Imaging of sacroiliitis—practice recommendations by ESSR

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Sacroiliitis is commonly seen in patients with axial spondyloarthritis, in whom timely diagnosis and treatment are crucial to prevent irreversible structural damage. Imaging has a prominent place in the diagnostic process and several new imaging techniques have been examined for this purpose. We present a summary of updated evidence-based practice recommendations for imaging of sacroiliitis. MRI remains the imaging modality of choice for patients with suspected sacroiliitis, using at least four sequences: coronal oblique T1-weighted and fluid-sensitive sequences, a perpendicular axial oblique sequence, and a sequence for optimal evaluation of the bone-cartilage interface. Both active inflammatory and structural lesions should be described in the report, indicating location and extent. Radiography and CT, especially low-dose CT, are reasonable alternatives when MRI is unavailable, as patients are often young. This is particularly true to evaluate structural lesions, at which CT excels. Dual-energy CT with virtual non-calcium images can be used to depict bone marrow edema. Knowledge of normal imaging features in children (e.g., flaring, blurring, or irregular appearance of the articular surface) is essential for interpreting sacroiliac joint MRI in children because these normal processes can simulate disease.

Clinical relevance statement

Sacroiliitis is a potentially debilitating disease if not diagnosed and treated promptly, before structural damage to the sacroiliac joints occurs. Imaging has a prominent place in the diagnostic process. We present a summary of practice recommendations for imaging of sacroiliitis, including several new imaging techniques.

Key Points

• MRI is the modality of choice for suspected inflammatory sacroiliitis, including a joint-line-specific sequence for optimal evaluation of the bone-cartilage interface to improve detection of erosions.

• Radiography and CT (especially low-dose CT) are reasonable alternatives when MRI is unavailable.

• Knowledge of normal imaging features in children is mandatory for interpretation of MRI of pediatric sacroiliac joints.

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Change history

  • 06 May 2024

    Correction of minor typographical error in guest editor's name.



Axial spondyloarthritis


Dual-energy CT


Juvenile spondyloarthropathy


Low-dose CT


Modified New York criteria


Sacroiliac joint


Short tau inversion recovery


T2-weighted fat-saturated


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This paper was endorsed by the Executive Council of the European Society of Radiology (ESR) and the Executive Committee of the European Society of Musculoskeletal Radiology (ESSR) in February 2024.


The authors state that this work has not received any funding.

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Correspondence to Lennart Jans.

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The scientific guarantor of this publication is Lennart Jans.

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evidence-based practice recommendations

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This Article belongs to the ESR Essentials series guest edited by Marc Dewey (Berlin/Germany).

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Vereecke, E., Diekhoff, T., Eshed, I. et al. ESR Essentials: Imaging of sacroiliitis—practice recommendations by ESSR. Eur Radiol (2024).

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