Article Text

Choose wisely: imaging for diagnosis of axial spondyloarthritis
  1. Torsten Diekhoff1,
  2. Iris Eshed2,
  3. Felix Radny1,
  4. Katharina Ziegeler1,
  5. Fabian Proft3,
  6. Juliane Greese1,
  7. Dominik Deppe1,
  8. Robert Biesen4,
  9. Kay Geert Hermann1,
  10. Denis Poddubnyy5
  1. 1Department of Radiology, Charité Universitätsmedizin Berlin, Berlin, Germany
  2. 2Radiology, Sheba Medical Center, Tel Hashomer, Israel
  3. 3Department of Gastroenterology, Infectiology and Rheumatology, Charite Universitatsmedizin Berlin Campus Benjamin Franklin, Berlin, Germany
  4. 4Department of Rheumatology and Clinical Immunology, Charité Universitätsmedizin Berlin, Berlin, Germany
  5. 5Division of Gastroenterology, Infectious Diseases and Rheumatology, Charité Universitätsmedizin Berlin, Berlin, Germany
  1. Correspondence to Torsten Diekhoff, Department of Radiology, Charité Universitätsmedizin Berlin, Berlin, Berlin, Germany; torsten.diekhoff{at}charite.de

Abstract

Objective To assess the diagnostic accuracy of radiography (X-ray, XR), CT and MRI of the sacroiliac joints for diagnosis of axial spondyloarthritis (axSpA).

Methods 163 patients (89 with axSpA; 74 with degenerative conditions) underwent XR, CT and MR. Three blinded experts categorised the imaging findings into axSpA, other diseases or normal in five separate reading rounds (XR, CT, MR, XR +MR, CT +MR). The clinical diagnosis served as reference standard. Sensitivity and specificity for axSpA and inter-rater reliability were compared.

Results XR showed lower sensitivity (66.3%) than MR (82.0%) and CT (76.4%) and also an inferior specificity of 67.6% vs 86.5% (MR) and 97.3% (CT). XR +MR was similar to MR alone (sensitivity 77.5 %/specificity 87.8%) while CT+MR was superior (75.3 %/97.3%). CT had the best inter-rater reliability (kappa=0.875), followed by MR (0.665) and XR (0.517). XR +MR was similar (0.662) and CT+MR (0.732) superior to MR alone.

Conclusions XR had inferior diagnostic accuracy and inter-rater reliability compared with cross-sectional imaging. MR alone was similar in diagnostic performance to XR+MR. CT had the best accuracy, strengthening the importance of structural lesions for the differential diagnosis in axSpA.

  • spondylitis
  • ankylosing
  • magnetic resonance imaging
  • low back pain

Data availability statement

Data are available on reasonable request. All data relevant to the study are included in the article or uploaded as online supplemental information. All source data including but not limited to scoring results and primary imaging are available from the corresponding author on request.

https://creativecommons.org/licenses/by/4.0/

This is an open access article distributed in accordance with the Creative Commons Attribution 4.0 Unported (CC BY 4.0) license, which permits others to copy, redistribute, remix, transform and build upon this work for any purpose, provided the original work is properly cited, a link to the licence is given, and indication of whether changes were made. See: https://creativecommons.org/licenses/by/4.0/.

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Data availability statement

Data are available on reasonable request. All data relevant to the study are included in the article or uploaded as online supplemental information. All source data including but not limited to scoring results and primary imaging are available from the corresponding author on request.

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Footnotes

  • Handling editor Josef S Smolen

  • TD and IE contributed equally.

  • Contributors TD: conception and design of the study, design of scoring system, image scoring, data evaluation, statistical calculations, article draft, critical revision of the manuscript for important intellectual content. IE: conception and design of the study, image scoring, data evaluation, critical revision of the manuscript for important intellectual content. FR: data management, critical revision of the manuscript for important intellectual content. KZ: image scoring, data evaluation, statistical calculations, critical revision of the manuscript for important intellectual content. FP: patient acquisition, data collection, critical revision of the manuscript for important intellectual content. JG: patient acquisition, data collection, critical revision of the manuscript for important intellectual content. DD: patient acquisition, data evaluation, critical revision of the manuscript for important intellectual content. RB: data evaluation, critical revision of the manuscript for important intellectual content. KGH: conception and design of the study, critical revision of the manuscript for important intellectual content. DP: conception and design of the study, statistical calculations, critical revision of the manuscript for important intellectual content.

  • Funding TD received a research grant from the Assessment of Spondyloarthritis international Society. Other than that, the authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests TD reports an ASAS research grant during the conduct of the study, personal fees from Canon MS, MSD, Roche and Novartis and an institutional grant from Canon MS outside the submitted work. DP reports grants and personal fees from AbbVie, Eli Lilly, MSD, Novartis, Pfizer and personal fees from Bristol-Myers Squibb, Roche, UCB, Biocad, GlaxoSmithKline and Gilead outside the submitted work. KGH reports personal fees from AbbVie, Novartis, Merck and Pfizer outside the submitted work. For the remaining authors none were declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.