Many contradictory views have been reported in the studies evaluating a connection between back pain features and MRI findings in the Spine and Sacroiliac (SI) Joints.

Recently, a group of investigators at Denmark conducted a study to examine the relationship between MRI findings at the SI joints and vertebral endplates and pain features considered to be suggestive of axial inflammation. Patients between 18-40 years suffering from persistent low back pain referred to an outpatient spine clinic, including an unknown proportion of axial spondyloarthritis patients were recruited. Data involved MRI of the spine and SI joints and self-reported responses to questions covering the Calin, Berlin, Assessment of Spondyloarthritis International Society, and Bailly inflammatory back pain (IBP) definitions.

Out of 1,020 patients, 53% were females with median age of 33 years. The results indicated positive connections between the SI joints MRI findings and pain characteristics, with odds ratios ranging from 1.4-2.7. SIJ bone marrow edema (BME)' was linked with ‘morning stiffness >60 minutes', ‘SIJ erosions' with the Calin, Berlin, and Bailly IBP definitions, ‘alternating buttock pain' and ‘good response to NSAIDs. SI joint fatty marrow deposition (FMD) was linked with the secret onset and SI joint sclerosis with pain at night. An association was found between the spinal MRI changes and IBP, odds ratios ranging from 1.4-2.0; ‘vertebral endplate BME' with, ‘morning stiffness', and ‘vertebral endplate FMD' with the Calin and Bailly IBP definitions, ‘improvement with exercise', ‘morning stiffness >30 min' and ‘pain worst in the morning'.

The recognized relationships between inflammatory MRI findings and pain characteristics show that axial inflammation to some extent produces a particular pain pattern. Therefore, the results add to the understanding of axial inflammatory processes. Though, all recognized correlations were weak, which compromises the use of IBP as a marker of axial inflammation.