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Suspected axial spondyloarthritis — SCE Rheumatology MCQ

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ModerateMusculoskeletal ImagingSuspected axial spondyloarthritisSCE Rheumatology

A 32-year-old woman has a 4-year history of low back pain that wakes her during the second half of the night, alternating buttock pain and prolonged morning stiffness that improves with exercise. She has had two episodes of acute anterior uveitis. Examination shows reduced lumbar flexion, and C-reactive protein is 18 mg/L. HLA-B27 is negative. Sacroiliac joint radiographs do not meet modified New York criteria. An unenhanced inflammatory back pain MRI, including T1-weighted and STIR sequences of the sacroiliac joints and whole spine, is reported by a general radiologist as showing a small non-specific focus of sacroiliac bone marrow oedema but not meeting ASAS/OMERACT criteria. Clinical suspicion of axial spondyloarthritis remains high. What is the most appropriate next step in the imaging pathway?

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Correct answer: B — Arrange specialist musculoskeletal radiology review of the existing MRI

The marked disparity between the strongly suggestive clinical phenotype and the initial MRI interpretation warrants specialist musculoskeletal radiology review. NICE advises that an MRI not meeting ASAS/OMERACT criteria does not exclude axial spondyloarthritis and specifically recommends considering specialist review when clinical suspicion and imaging findings are discordant. If the diagnosis remains unconfirmed after review and suspicion remains high, a follow-up MRI may subsequently be considered. Immediate gadolinium-enhanced MRI is inappropriate because the recommended inflammatory back pain protocol is unenhanced and uses T1-weighted and fluid-sensitive sequences; contrast is not required routinely to identify osteitis. CT depicts erosions and other structural lesions well but cannot establish active inflammation and is not the next investigation in the NICE diagnostic pathway. Bone scintigraphy should not be offered for suspected axial spondyloarthritis because of inadequate diagnostic performance. A negative or formally non-classifying MRI cannot independently exclude the diagnosis, particularly in an HLA-B27-negative woman with inflammatory back pain, recurrent uveitis and elevated inflammatory markers.

Reference: Spondyloarthritis in over 16s: diagnosis and management — Recommendations (Published 28 February 2017; imaging recommendation clarified May 2017) — https://www.nice.org.uk/guidance/NG65/chapter/Recommendations Spondyloarthritis in over 16s: diagnosis and management — Overview (Last reviewed 4 March 2025) — https://www.nice.org.uk/guidance/ng65