Skeletal Radiology

, Volume 47, Issue 5, pp 683–693 | Cite as

MRI of the sacroiliac joints in spondyloarthritis: the added value of intra-articular signal changes for a ‘positive MRI’

  • Frederiek Laloo
  • N. Herregods
  • J. L. Jaremko
  • K. Verstraete
  • L. Jans
Scientific Article



To determine if intra-articular signal changes at the sacroiliac joint space on MRI have added diagnostic value for spondyloarthritis, when compared to bone marrow edema (BME).

Materials and methods

A retrospective study was performed on the MRIs of sacroiliac joints of 363 patients, aged 16–45 years, clinically suspected of sacroiliitis. BME of the sacroiliac joints was correlated to intra-articular sacroiliac joint MR signal changes: high T1 signal, fluid signal, ankylosis and vacuum phenomenon (VP). These MRI findings were correlated with final clinical diagnosis. Sensitivity (SN), specificity (SP), likelihood ratios (LR), predictive values and post-test probabilities were calculated.


BME had SN of 68.9%, SP of 74.0% and LR+ of 2.6 for diagnosis of spondyloarthritis. BME in absence of intra-articular signal changes had a lower SN and LR+ for spondyloarthritis (SN = 20.5%, LR+ 1.4). Concomitant BME and high T1 signal (SP = 97.2%, LR + = 10.5), BME and fluid signal (SP = 98.6%, LR + = 10.3) or BME and ankylosis (SP = 100%) had higher SP and LR+ for spondyloarthritis. Concomitant BME and VP had low LR+ for spondyloarthritis (SP = 91%, LR + =0.9). When BME was absent, intra-articular signal changes were less prevalent, but remained highly specific for spondyloarthritis.


Our results suggest that both periarticular and intra-articular MR signal of the sacroiliac joint should be examined to determine whether an MRI is ‘positive’ or ‘not positive’ for sacroiliitis associated with spondyloarthritis.


MRI Spondyloarthritis Sacroiliac joint Sacroiliitis Ankylosis 


Compliance with ethical standards

Conflicts of interest

The authors declare that they have no conflicts of interest.

Ethical approval

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards.

Informed consent

Informed consent was obtained from all individual participants included in the study.


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Copyright information

© ISS 2017

Authors and Affiliations

  • Frederiek Laloo
    • 1
  • N. Herregods
    • 1
  • J. L. Jaremko
    • 2
  • K. Verstraete
    • 1
  • L. Jans
    • 1
  1. 1.Department of Radiology and Medical ImagingGhent University HospitalGhentBelgium
  2. 2.Department of Radiology & Diagnostic ImagingUniversity of Alberta HospitalEdmontonCanada

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