Magnetic resonance imaging changes of sacroiliac joints in patients with recent-onset inflammatory back pain: inter-reader reliability and prevalence of abnormalities

Liesbeth Heuft-Dorenbosch,Désirée Van Der Heijde,Robert Landewé,René Weijers,Sjef Van Der Linden

doi:10.1186/ar1859

Liesbeth Heuft-Dorenbosch, Désirée Van Der Heijde + Show 3 more

Open Access

https://doi.org/10.1186/ar1859

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Abstract

To study the inter-reader reliability of detecting abnormalities of sacroiliac (SI) joints in patients with recent-onset inflammatory back pain by magnetic resonance imaging (MRI), and to study the prevalence of inflammation and structural changes at various sites of the SI joints.Sixty-eight patients with inflammatory back pain (at least four of the five following criteria: symptom onset before age 40, insidious onset, morning stiffness, duration >3 months, improvement with exercise — or three out of five of these plus night pain) were included (38% male; mean age, 34.9 years [standard deviation 10.3]; 46% HLA-B27-positive; mean symptom duration, 18 months), with symptom duration <2 years. A MRI scan of the SI joints was made in the coronal plane with the following sequences: T1-weighted spin echo, short-tau inversion recovery, T2-weighted fast-spin echo with fat saturation, and T1-spin echo with fat saturation after the administration of gadolinium. Both SI joints were scored for inflammation (separately for subchondral bone and bone marrow, joint space, joint capsule, ligaments) as well as for structural changes (erosions, sclerosis, ankylosis), by two observers independently. Agreement between the two readers was analysed by concordance and discordance rates and by kappa statistics.Inflammation was present in 32 SI joints of 22 patients, most frequently located in bone marrow and/or subchondral bone (29 joints in 21 patients). Readers agreed on the presence of inflammation in 85% of the cases in the right SI joint and in 78% of the cases in the left SI joint. Structural changes on MRI were present in 11 patients. Ten of these 11 patients also showed signs of inflammation.Agreement on the presence or absence of inflammation and structural changes of SI joints by MRI was acceptable, and was sufficiently high to be useful in ascertaining inflammatory and structural changes due to sacroiliitis. About one-third of patients with recent-onset inflammatory back pain show inflammation, and about one-sixth show structural changes in at least one SI joint.

Highlights

Ankylosing spondylitis (AS) is a chronic rheumatic condition, characterized by inflammation of the axial skeleton, the sacroiliac (SI) joints
A magnetic resonance imaging (MRI) scan of the SI joints was made in the coronal plane with the following sequences: T1-weighted spin echo, short-tau inversion recovery, T2-weighted fast-spin echo with fat saturation, and T1-spin echo with fat saturation after the administration of gadolinium
Both SI joints were scored for inflammation as well as for structural changes, by two observers independently

Summary

Introduction

Ankylosing spondylitis (AS) is a chronic rheumatic condition, characterized by inflammation of the axial skeleton, the sacroiliac (SI) joints. Patients fulfil classification criteria for AS if characteristic radiological changes of the SI joint are present, together with defined clinical symptoms and findings [1]. AS belongs to the group of seronegative spondyloarthritides (SpA). The European Spondylarthropathy Study Group has developed classification criteria for SpA [2]. Sacroiliitis is a characteristic feature of AS and is frequently found in patients with SpA, it is not obligatory. Patients with sacroiliitis experience chronic low back pain with an inflammatory pattern that often begins in young adulthood

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