CC BY-NC-ND 4.0 · Rofo 2024; 196(06): 550-559
DOI: 10.1055/a-2193-1970
Review

New Bone Formation in Axial Spondyloarthritis: A Review

Knochenneubildung bei axialer Spondyloarthritis: eine Übersichtsarbeit
1   Department of Radiology (Campus Charité Mitte), Charité Universitätsmedizin Berlin, Germany
2   Charité – Universitätsmedizin, Berlin Institute of Health at Charite, Berlin, Germany
,
Dominik Deppe
1   Department of Radiology (Campus Charité Mitte), Charité Universitätsmedizin Berlin, Germany
,
1   Department of Radiology (Campus Charité Mitte), Charité Universitätsmedizin Berlin, Germany
,
1   Department of Radiology (Campus Charité Mitte), Charité Universitätsmedizin Berlin, Germany
2   Charité – Universitätsmedizin, Berlin Institute of Health at Charite, Berlin, Germany
› Institutsangaben

Abstract

Background

Axial spondyloarthritis (axSpA) is a chronic inflammatory disease primarily affecting the sacroiliac joints (SIJs) and the spine. Imaging plays a crucial role in the diagnosis of axSpA, with magnetic resonance imaging (MRI) and radiography being the primary modalities used in clinical practice. New bone formation occurs in both the spine (non-bridging and bridging syndesmophytes, transdiscal ankylosis, and ankylosis of small joints and posterior elements) and the SIJs (backfill and ankylosis). New bone formation indicates advanced axSpA.

Method

This review explores the role of imaging in the diagnosis and monitoring of axSpA, focusing on the significance of new bone formation, and provides an overview of the characteristic imaging findings of new bone formation in axSpA in each imaging modality.

Conclusion

Imaging methods, such as X-ray, MRI, and CT, have different diagnostic accuracies for detecting structural lesions and new bone formation. Each modality has its strengths and weaknesses, and the choice depends on the specific clinical context. Imaging is crucial for the diagnosis and monitoring of axSpA, particularly for the detection of new bone formation. Different imaging techniques provide valuable information about disease progression and treatment response. Understanding the significance of new bone formation and its detection using imaging modalities is essential for the accurate diagnosis and effective management of patients with axSpA.

Key Points

  • New bone formation is a hallmark feature of advanced axial spondyloarthritis.

  • New bone formation occurs both in the spine and in the sacroiliac joints.

  • Differentiation of new bone formation in axial spondyloarthritis from that in other conditions such as diffuse idiopathic skeletal hyperostosis and from osteophytes is essential.

  • Imaging methods, such as X-ray, MRI, and CT, have different diagnostic accuracies for detecting new bone formation.

Citation Format

  • Ulas S, Deppe D, Ziegeler K et al. New Bone Formation in Axial Spondyloarthritis: A Review. Fortschr Röntgenstr 2024; 196: 550 – 559

Zusammenfassung

Hintergrund

Die axiale Spondyloarthritis (axSpA) ist eine chronisch entzündliche Erkrankung, die vor allem das Sakroiliakalgelenk (SIG) und die Wirbelsäule betrifft. Die Bildgebung spielt bei der Diagnose der axSpA eine entscheidende Rolle, wobei MRT und Röntgenuntersuchung die wichtigsten Untersuchungsmethoden in der klinischen Praxis sind. Knochenneubildung tritt sowohl an der Wirbelsäule (nicht brückenbildende und brückenbildende Syndesmophyten, transdiskale Ankylose und Ankylose der kleinen Gelenke und der hinteren Elemente) als auch am Sakroiliakalgelenk (Backfill und Ankylose) auf. Das Vorhandensein von Knochenneubildung weist auf fortgeschrittene Stadien der axSpA hin.

Methode

In dieser Übersichtsarbeit wird die Rolle der Bildgebung bei der Diagnose und Überwachung der axSpA untersucht, wobei der Schwerpunkt auf der Bedeutung der Knochenneubildung liegt, und es wird ein Überblick über die charakteristischen Bildgebungsbefunde der Knochenneubildung bei axSpA in den jeweiligen Bildgebungsmodalitäten gegeben.

Schlussfolgerung

Bildgebende Verfahren wie Röntgen, MRT und CT haben unterschiedliche diagnostische Genauigkeiten bei der Erkennung struktureller Läsionen und Knochenneubildung. Jede Modalität hat ihre Stärken und Schwächen, und die Wahl hängt vom jeweiligen klinischen Kontext ab. Die Bildgebung ist für die Diagnose und Überwachung der axSpA von entscheidender Bedeutung, insbesondere für den Nachweis von Knochenneubildung. Verschiedene bildgebende Verfahren liefern wertvolle Informationen über das Fortschreiten der Krankheit und das Ansprechen auf die Behandlung. Das Verständnis der Bedeutung der Knochenneubildung und ihrer Erkennung durch bildgebende Verfahren ist für eine genaue Diagnose und eine wirksame Behandlung der axSpA unerlässlich.

Kernaussagen

  • Knochenneubildung ist kennzeichnende Veränderung bei meist fortgeschrittener axialer Spondyloarthritis.

  • Knochenneubildung kommt sowohl an der Wirbelsäule als auch am Sakroiliakalgelenk vor.

  • Die Unterscheidung zwischen Knochenneubildung bei axialer Spondyloarthritis und anderen Differenzialdiagnosen, wie der diffusen idiopathischen skeletalen Hyperostosis, sowie degenerativ bedingten Spondylophyten ist essenziell.

  • Bildgebende Verfahren wie Röntgen, MRT und CT haben unterschiedliche diagnostische Genauigkeiten bei der Darstellung von Knochenneubildung.



Publikationsverlauf

Eingereicht: 27. Juni 2023

Angenommen: 06. September 2023

Artikel online veröffentlicht:
09. November 2023

© 2023. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commecial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/)

Georg Thieme Verlag KG
Rüdigerstraße 14, 70469 Stuttgart, Germany

 
  • References

  • 1 Braun J, Bollow M, Remlinger G. et al. Prevalence of spondylarthropathies in HLA-B27 positive and negative blood donors. Arthritis Rheum 1998; 41: 58-67 DOI: 10.1002/1529-0131(199801)41:1<58::AID-ART8>3.0.CO;2-G.
  • 2 Sieper J, Rudwaleit M, Khan MA. et al. Concepts and epidemiology of spondyloarthritis. Best Pract Res Clin Rheumatol 2006; 20: 401-417 DOI: 10.1016/j.berh.2006.02.001.
  • 3 Rudwaleit M, Jurik AG, Hermann KG. et al. Defining active sacroiliitis on magnetic resonance imaging (MRI) for classification of axial spondyloarthritis: a consensual approach by the ASAS/OMERACT MRI group. Ann Rheum Dis 2009; 68: 1520-1527 DOI: 10.1136/ard.2009.110767.
  • 4 Braun J, Sieper J. Ankylosing spondylitis. Lancet 2007; 369: 1379-1390 DOI: 10.1016/S0140-6736(07)60635-7.
  • 5 Navarro-Compan V, Sepriano A, El-Zorkany B. et al. Axial spondyloarthritis. Ann Rheum Dis 2021; 80: 1511-1521 DOI: 10.1136/annrheumdis-2021-221035.
  • 6 Rudwaleit M, van der Heijde D, Khan MA. et al. How to diagnose axial spondyloarthritis early. Ann Rheum Dis 2004; 63: 535-543 DOI: 10.1136/ard.2003.011247.
  • 7 Rudwaleit M, van der Heijde D, Landewe R. et al. The development of Assessment of SpondyloArthritis international Society classification criteria for axial spondyloarthritis (part II): validation and final selection. Ann Rheum Dis 2009; 68: 777-783 DOI: 10.1136/ard.2009.108233.
  • 8 Kiltz U, Braun J. Dgrh. et al. [Long version on the S3 guidelines for axial spondyloarthritis including Bechterew’s disease and early forms, Update 2019: Evidence-based guidelines of the German Society for Rheumatology (DGRh) and participating medical scientific specialist societies and other organizations]. Z Rheumatol 2019; 78: 3-64 DOI: 10.1007/s00393-019-0670-3.
  • 9 Lambert RG, Bakker PA, van der Heijde D. et al. Defining active sacroiliitis on MRI for classification of axial spondyloarthritis: update by the ASAS MRI working group. Ann Rheum Dis 2016; 75: 1958-1963 DOI: 10.1136/annrheumdis-2015-208642.
  • 10 Hoballah A, Lukas C, Leplat C. et al. MRI of sacroiliac joints for the diagnosis of axial SpA: prevalence of inflammatory and structural lesions in nulliparous, early postpartum and late postpartum women. Ann Rheum Dis 2020; 79: 1063-1069 DOI: 10.1136/annrheumdis-2020-217208.
  • 11 Eshed I, Miloh-Raz H, Dulitzki M. et al. Peripartum changes of the sacroiliac joints on MRI: increasing mechanical load correlating with signs of edema and inflammation kindling spondyloarthropathy in the genetically prone. Clin Rheumatol 2015; 34: 1419-1426 DOI: 10.1007/s10067-015-2976-0.
  • 12 Baraliakos X, Ostergaard M, Lambert RG. et al. MRI lesions of the spine in patients with axial spondyloarthritis: an update of lesion definitions and validation by the ASAS MRI working group. Ann Rheum Dis 2022; DOI: 10.1136/annrheumdis-2021-222081.
  • 13 Maksymowych WP, Lambert RG, Ostergaard M. et al. MRI lesions in the sacroiliac joints of patients with spondyloarthritis: an update of definitions and validation by the ASAS MRI working group. Ann Rheum Dis 2019; 78: 1550-1558 DOI: 10.1136/annrheumdis-2019-215589.
  • 14 Vleeming A, Schuenke MD, Masi AT. et al. The sacroiliac joint: an overview of its anatomy, function and potential clinical implications. J Anat 2012; 221: 537-567 DOI: 10.1111/j.1469-7580.2012.01564.x.
  • 15 Hermann KG, Baraliakos X, van der Heijde DM. et al. Descriptions of spinal MRI lesions and definition of a positive MRI of the spine in axial spondyloarthritis: a consensual approach by the ASAS/OMERACT MRI study group. Ann Rheum Dis 2012; 71: 1278-1288 DOI: 10.1136/ard.2011.150680.
  • 16 Baraliakos X, Listing J, Rudwaleit M. et al. Progression of radiographic damage in patients with ankylosing spondylitis: defining the central role of syndesmophytes. Ann Rheum Dis 2007; 66: 910-915 DOI: 10.1136/ard.2006.066415.
  • 17 Jans L, van Langenhove C, Van Praet L. et al. Diagnostic value of pelvic enthesitis on MRI of the sacroiliac joints in spondyloarthritis. Eur Radiol 2014; 24: 866-871 DOI: 10.1007/s00330-013-3074-9.
  • 18 Cortes A, Hadler J. International Genetics of Ankylosing Spondylitis C. et al. Identification of multiple risk variants for ankylosing spondylitis through high-density genotyping of immune-related loci. Nat Genet 2013; 45: 730-738 DOI: 10.1038/ng.2667.
  • 19 Baraliakos X, Listing J, Rudwaleit M. et al. The relationship between inflammation and new bone formation in patients with ankylosing spondylitis. Arthritis Res Ther 2008; 10: R104 DOI: 10.1186/ar2496.
  • 20 Jacques P, Lambrecht S, Verheugen E. et al. Proof of concept: enthesitis and new bone formation in spondyloarthritis are driven by mechanical strain and stromal cells. Ann Rheum Dis 2014; 73: 437-445 DOI: 10.1136/annrheumdis-2013-203643.
  • 21 Ward MM, Reveille JD, Learch TJ. et al. Occupational physical activities and long-term functional and radiographic outcomes in patients with ankylosing spondylitis. Arthritis Rheum 2008; 59: 822-832 DOI: 10.1002/art.23704.
  • 22 Masi AT. Might axial myofascial properties and biomechanical mechanisms be relevant to ankylosing spondylitis and axial spondyloarthritis?. Arthritis Res Ther 2014; 16: 107 DOI: 10.1186/ar4532.
  • 23 Sardoo AM, Neto A, Pinheiro Torres R. et al. The role of muscle in the susceptibility and progression of axial Spondyloarthritis: The MyoSpA Study Protocol. Acta Reumatol Port 2021; 46: 342-349
  • 24 Van Mechelen M, Lories RJ. Microtrauma: no longer to be ignored in spondyloarthritis?. Curr Opin Rheumatol 2016; 28: 176-180 DOI: 10.1097/BOR.0000000000000254.
  • 25 Baraliakos X, Heldmann F, Callhoff J. et al. Which spinal lesions are associated with new bone formation in patients with ankylosing spondylitis treated with anti-TNF agents? A long-term observational study using MRI and conventional radiography. Ann Rheum Dis 2014; 73: 1819-1825 DOI: 10.1136/annrheumdis-2013-203425.
  • 26 Maksymowych WP, Wichuk S, Chiowchanwisawakit P. et al. Fat metaplasia and backfill are key intermediaries in the development of sacroiliac joint ankylosis in patients with ankylosing spondylitis. Arthritis Rheumatol 2014; 66: 2958-2967 DOI: 10.1002/art.38792.
  • 27 Romanus R, Yden S. Destructive and ossifying spondylitic changes in rheumatoid ankylosing spondylitis (pelvo-spondylitis ossificans). Acta Orthop Scand 1952; 22: 88-99 DOI: 10.3109/17453675208988998.
  • 28 Engfeldt B, Romanus R, Yden S. Histological studies of pelvo-spondylitis ossificans (ankylosing spondylitis) correlated with clinical and radiological findings. Ann Rheum Dis 1954; 13: 219-228 DOI: 10.1136/ard.13.3.219.
  • 29 Chiowchanwisawakit P, Lambert RG, Conner-Spady B. et al. Focal fat lesions at vertebral corners on magnetic resonance imaging predict the development of new syndesmophytes in ankylosing spondylitis. Arthritis Rheum 2011; 63: 2215-2225 DOI: 10.1002/art.30393.
  • 30 Maksymowych WP, Chiowchanwisawakit P, Clare T. et al. Inflammatory lesions of the spine on magnetic resonance imaging predict the development of new syndesmophytes in ankylosing spondylitis: evidence of a relationship between inflammation and new bone formation. Arthritis Rheum 2009; 60: 93-102 DOI: 10.1002/art.24132.
  • 31 Braun J, Bollow M, Sieper J. Radiologic diagnosis and pathology of the spondyloarthropathies. Rheum Dis Clin North Am 1998; 24: 697-735 DOI: 10.1016/s0889-857x(05)70038-7.
  • 32 Khan MA, van der Linden SM, Kushner I. et al. Spondylitic disease without radiologic evidence of sacroiliitis in relatives of HLA-B27 positive ankylosing spondylitis patients. Arthritis Rheum 1985; 28: 40-43 DOI: 10.1002/art.1780280107.
  • 33 Lee SJ, Kim JY, Choi YY. et al. Predictive value of semi-quantitative index from F-18-fluoride PET/CT for treatment response in patients with ankylosing spondylitis. Eur J Radiol 2020; 129: 109048 DOI: 10.1016/j.ejrad.2020.109048.
  • 34 Idolazzi L, Salgarello M, Gatti D. et al. 18F-fluoride PET/CT for detection of axial involvement in ankylosing spondylitis: correlation with disease activity. Ann Nucl Med 2016; 30: 430-434 DOI: 10.1007/s12149-016-1080-0.
  • 35 Raynal M, Bouderraoui F, Ouichka R. et al. Performance of (18)F-sodium fluoride positron emission tomography with computed tomography to assess inflammatory and structural sacroiliitis on magnetic resonance imaging and computed tomography, respectively, in axial spondyloarthritis. Arthritis Res Ther 2019; 21: 119 DOI: 10.1186/s13075-019-1903-1.
  • 36 Maksymowych WP. MRI and X-ray in axial spondyloarthritis: the relationship between inflammatory and structural changes. Arthritis Res Ther 2012; 14: 207 DOI: 10.1186/ar3786.
  • 37 Sieper J, Rudwaleit M, Baraliakos X. et al. The Assessment of SpondyloArthritis international Society (ASAS) handbook: a guide to assess spondyloarthritis. Ann Rheum Dis 2009; 68 (Suppl. 02) ii1-ii44 DOI: 10.1136/ard.2008.104018.
  • 38 Laloo F, Herregods N, Jaremko JL. et al. New bone formation in the intervertebral joint space in spondyloarthritis: An MRI study. Eur J Radiol 2018; 109: 210-217 DOI: 10.1016/j.ejrad.2018.11.007.
  • 39 Braun J, Kiltz U, Baraliakos X. Significance of structural changes in the sacroiliac joints of patients with axial spondyloarthritis detected by MRI related to patients symptoms and functioning. Ann Rheum Dis 2022; 81: 11-14 DOI: 10.1136/annrheumdis-2021-221406.
  • 40 Baraliakos X. Imaging in Axial Spondyloarthritis. Isr Med Assoc J 2017; 19: 712-718
  • 41 Ramiro S, van der Heijde D, van Tubergen A. et al. Higher disease activity leads to more structural damage in the spine in ankylosing spondylitis: 12-year longitudinal data from the OASIS cohort. Ann Rheum Dis 2014; 73: 1455-1461 DOI: 10.1136/annrheumdis-2014-205178.
  • 42 Weber U, Pedersen SJ, Ostergaard M. et al. Can erosions on MRI of the sacroiliac joints be reliably detected in patients with ankylosing spondylitis? – A cross-sectional study. Arthritis Res Ther 2012; 14: R124 DOI: 10.1186/ar3854.
  • 43 Diekhoff T, Poddubnyy D, Proft F. et al. New bone formation at the sacroiliac joint in axial spondyloarthritis: characterization of backfill in MRI and CT. Rheumatology (Oxford) 2023; DOI: 10.1093/rheumatology/kead142.
  • 44 Laloo F, Herregods N, Varkas G. et al. MR signal in the sacroiliac joint space in spondyloarthritis: a new sign. Eur Radiol 2017; 27: 2024-2030 DOI: 10.1007/s00330-016-4587-9.
  • 45 Laloo F, Herregods N, Jaremko JL. et al. MRI of the sacroiliac joints in spondyloarthritis: the added value of intra-articular signal changes for a “positive MRI”. Skeletal Radiol 2018; 47: 683-693 DOI: 10.1007/s00256-017-2830-3.
  • 46 Zhang Y, Guo Z, Wang L. et al. Baseline Severity of Sacroiliitis and Extensive Fat Metaplasia Predicts the Progression of Backfill at the Sacroiliac Joint in Patients With Axial Spondyloarthritis. Front Immunol 2022; 13: 887470 DOI: 10.3389/fimmu.2022.887470.
  • 47 Wetterslev M, Ostergaard M, Sorensen IJ. et al. Development and Validation of 3 Preliminary MRI Sacroiliac Joint Composite Structural Damage Scores in a 5-year Longitudinal Axial Spondyloarthritis Study. J Rheumatol 2021; 48: 1537-1546 DOI: 10.3899/jrheum.201075.
  • 48 Hu Z, Wang X, Qi J. et al. Backfill is a specific sign of axial spondyloarthritis seen on MRI. Joint Bone Spine 2016; 83: 179-183 DOI: 10.1016/j.jbspin.2015.05.011.
  • 49 Heuft-Dorenbosch L, Landewe R, Weijers R. et al. Performance of various criteria sets in patients with inflammatory back pain of short duration; the Maastricht early spondyloarthritis clinic. Ann Rheum Dis 2007; 66: 92-98 DOI: 10.1136/ard.2006.053918.
  • 50 Maksymowych WP, Wichuk S, Dougados M. et al. Modification of structural lesions on MRI of the sacroiliac joints by etanercept in the EMBARK trial: a 12-week randomised placebo-controlled trial in patients with non-radiographic axial spondyloarthritis. Ann Rheum Dis 2018; 77: 78-84 DOI: 10.1136/annrheumdis-2017-211605.
  • 51 Mogard E, Lindqvist E, Bremander A. et al. Risk factors for development and persistence of chronic widespread pain in spondyloarthritis: a population-based two-year follow-up study. Scand J Rheumatol 2019; 48: 460-468 DOI: 10.1080/03009742.2019.1602163.
  • 52 Kuperus JS, Waalwijk JF, Regan EA. et al. Simultaneous occurrence of ankylosing spondylitis and diffuse idiopathic skeletal hyperostosis: a systematic review. Rheumatology (Oxford) 2018; 57: 2120-2128 DOI: 10.1093/rheumatology/key211.
  • 53 de Hooge M, van den Berg R, Navarro-Compan V. et al. Patients with chronic back pain of short duration from the SPACE cohort: which MRI structural lesions in the sacroiliac joints and inflammatory and structural lesions in the spine are most specific for axial spondyloarthritis?. Ann Rheum Dis 2016; 75: 1308-1314 DOI: 10.1136/annrheumdis-2015-207823.
  • 54 Diekhoff T, Lambert R, Hermann KG. MRI in axial spondyloarthritis: understanding an “ASAS-positive MRI” and the ASAS classification criteria. Skeletal Radiol 2022; 51: 1721-1730 DOI: 10.1007/s00256-022-04018-4.
  • 55 Mau W, Zeidler H, Mau R. et al. Clinical features and prognosis of patients with possible ankylosing spondylitis. Results of a 10-year followup. J Rheumatol 1988; 15: 1109-1114
  • 56 Lambert RGW, Hermann KGA, Diekhoff T. Low-dose computed tomography for axial spondyloarthritis: update on use and limitations. Curr Opin Rheumatol 2021; 33: 326-332 DOI: 10.1097/BOR.0000000000000803.
  • 57 Diekhoff T, Hermann KGA, Lambert RG. Future of Low-Dose Computed Tomography and Dual-Energy Computed Tomography in Axial Spondyloarthritis. Curr Rheumatol Rep 2022; 24: 198-205 DOI: 10.1007/s11926-022-01075-5.
  • 58 Poddubnyy D, Diekhoff T, Baraliakos X. et al. Diagnostic evaluation of the sacroiliac joints for axial spondyloarthritis: should MRI replace radiography?. Ann Rheum Dis 2022; 81: 1486-1490 DOI: 10.1136/ard-2022-222986.
  • 59 Diekhoff T, Hermann KG, Greese J. et al. Comparison of MRI with radiography for detecting structural lesions of the sacroiliac joint using CT as standard of reference: results from the SIMACT study. Ann Rheum Dis 2017; 76: 1502-1508 DOI: 10.1136/annrheumdis-2016-210640.
  • 60 Maksymowych WP, Claudepierre P, de Hooge M. et al. Structural changes in the sacroiliac joint on MRI and relationship to ASDAS inactive disease in axial spondyloarthritis: a 2-year study comparing treatment with etanercept in EMBARK to a contemporary control cohort in DESIR. Arthritis Res Ther 2021; 23: 43 DOI: 10.1186/s13075-021-02428-8.
  • 61 Lee S, Lee JY, Hwang JH. et al. Clinical importance of inflammatory facet joints of the spine in ankylosing spondylitis: a magnetic resonance imaging study. Scand J Rheumatol 2016; 45: 491-498 DOI: 10.3109/03009742.2016.1150506.
  • 62 van der Linden S, Valkenburg HA, Cats A. Evaluation of diagnostic criteria for ankylosing spondylitis. A proposal for modification of the New York criteria. Arthritis Rheum 1984; 27: 361-368 DOI: 10.1002/art.1780270401.
  • 63 Averns HL, Oxtoby J, Taylor HG. et al. Radiological outcome in ankylosing spondylitis: use of the Stoke Ankylosing Spondylitis Spine Score (SASSS). Br J Rheumatol 1996; 35: 373-376 DOI: 10.1093/rheumatology/35.4.373.
  • 64 Creemers MC, Franssen MJ, van’t Hof MA. et al. Assessment of outcome in ankylosing spondylitis: an extended radiographic scoring system. Ann Rheum Dis 2005; 64: 127-129 DOI: 10.1136/ard.2004.020503.
  • 65 van der Heijde D, Braun J, Deodhar A. et al. Modified stoke ankylosing spondylitis spinal score as an outcome measure to assess the impact of treatment on structural progression in ankylosing spondylitis. Rheumatology (Oxford) 2019; 58: 388-400 DOI: 10.1093/rheumatology/key128.
  • 66 Braun J, Baraliakos X, Golder W. et al. Analysing chronic spinal changes in ankylosing spondylitis: a systematic comparison of conventional × rays with magnetic resonance imaging using established and new scoring systems. Ann Rheum Dis 2004; 63: 1046-1055 DOI: 10.1136/ard.2003.019968.
  • 67 Deppe D, Hermann KG, Proft F. et al. CT-like images of the sacroiliac joint generated from MRI using susceptibility-weighted imaging (SWI) in patients with axial spondyloarthritis. RMD Open 2021; 7 DOI: 10.1136/rmdopen-2021-001656.
  • 68 de Koning A, de Bruin F, van den Berg R. et al. Low-dose CT detects more progression of bone formation in comparison to conventional radiography in patients with ankylosing spondylitis: results from the SIAS cohort. Ann Rheum Dis 2018; 77: 293-299 DOI: 10.1136/annrheumdis-2017-211989.
  • 69 de Bruin F, de Koning A, van den Berg R. et al. Development of the CT Syndesmophyte Score (CTSS) in patients with ankylosing spondylitis: data from the SIAS cohort. Ann Rheum Dis 2018; 77: 371-377 DOI: 10.1136/annrheumdis-2017-212553.
  • 70 Gervaise A, Osemont B, Lecocq S. et al. CT image quality improvement using Adaptive Iterative Dose Reduction with wide-volume acquisition on 320-detector CT. Eur Radiol 2012; 22: 295-301 DOI: 10.1007/s00330-011-2271-7.
  • 71 Buchbender C, Ostendorf B, Ruhlmann V. et al. Hybrid 18F-labeled Fluoride Positron Emission Tomography/Magnetic Resonance (MR) Imaging of the Sacroiliac Joints and the Spine in Patients with Axial Spondyloarthritis: A Pilot Study Exploring the Link of MR Bone Pathologies and Increased Osteoblastic Activity. J Rheumatol 2015; 42: 1631-1637 DOI: 10.3899/jrheum.150250.
  • 72 Sawicki LM, Lutje S, Baraliakos X. et al. Dual-phase hybrid (18) F-Fluoride Positron emission tomography/MRI in ankylosing spondylitis: Investigating the link between MRI bone changes, regional hyperaemia and increased osteoblastic activity. J Med Imaging Radiat Oncol 2018; 62: 313-319 DOI: 10.1111/1754-9485.12687.
  • 73 Kuwert T, Schmidkonz C, Prante O. et al. FAPI PET Opens a New Window to Understanding Immune-Mediated Inflammatory Diseases. J Nucl Med 2022; 63: 1136-1137 DOI: 10.2967/jnumed.122.263922.