Manouk de Hooge, Abstract Co-Author: Nothing to Disclose

Jean-Baptiste Pialat MD, Abstract Co-Author: Nothing to Disclose

Antoine A. Feydy MD, Presenter: Nothing to Disclose

Monique Reijnierse MD, Abstract Co-Author: Nothing to Disclose

Maxime Dougados, Abstract Co-Author: Nothing to Disclose

Desiree M. F. M. Van Der Heijde MD, PhD, Abstract Co-Author: Nothing to Disclose

Background: Since 2012, a cut-off value of ≥3 inflammatory lesions was suggested by the ASAS/OMERACT group, as positive MRI of the spine (MRI-spine). Moreover, fatty lesions on MRI-spine are associated with axial Spondyloarthritis (axSpA). Objectives: To determine the prevalence of inflammatory (BME) and fatty lesions on MRI of the spine in patients with and without axSpA.  

Patients aged 18-50 with inflammatory back pain (≥3 months, ≤3 years) from 25 centres in France were included in the DESIR-cohort (n=708). All available baseline MRIs were independently scored by 2 well-calibrated readers, blinded to any other data. In case of disagreement, an experienced radiologist served as adjudicator. BME and fatty lesions typical for axSpA were scored when visible on ≥2 consecutive slices. Prevalence of MRI lesions was calculated based on several cut-offs and lesions were considered present if 2/3 readers agreed.

All patients with symptom onset <45 y with MRI-spine (n=549) were included in the analyses. Patients fulfilling the ASAS criteria could either fulfill both arms, only the imaging arm or only the clinical arm. The first 2 groups were subdivided; patients with radiographic sacroiliitis (mNY+) & sacroiliitis on MRI (MRI+), patients with mNY+ & no sacroiliitis on MRI (MRI-), patients without radiographic sacroiliitis (mNY-) & MRI+. BME lesions occur in all different subgroups of the ASAS criteria and in patients without axSpA. The prevalence in no SpA group (which can be seen as false positives) is only 6.1%. With a cut-off ≥2 BME lesions false positives drop below 5% while the prevalence in the ASAS axSpA groups is still reasonable. Especially prevalence in patients with mNY+ & MRI+ is very high; 61.9% (both arms positive) and 43.8% (imaging arm only positive). Fatty lesions are seen slightly less often seen in all patient groups.

In a low percentage of patients without axSpA BME and fatty lesions is found indicating that spinal BME and fatty lesions are specific for patients with axSpA. These lesions are especially prevalent in patients with sacroiliitis on imaging. In this cohort, a cut-off ≥2 or ≥3 BME lesions and similarly ≥2 or ≥3 fatty lesions discriminate best between patients with and without axSpA.

Spinal BME and fatty lesions on MRI are especially prevalent in patients with sacroiliitis on imaging.

de Hooge, M, Pialat, J, Feydy, A, Reijnierse, M, Dougados, M, Van Der Heijde, D, Prevalence of MRI Spinal Lesions Typical for Axial Spondyloarthritis in Patients with Inflammatory Back Pain.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14045784.html