MRI reveals sacroiliac inflammation in both healthy runners, patients with spondyloarthritis
SAN DIEGO — Although sacroiliac MRI has been extensively relied on to diagnose axial spondyloarthritis, research presented at the American College of Rheumatology Annual Meeting demonstrated that similar inflammation of sacroiliac joints was observed among even healthy individuals, highlighting the need for complementary diagnostic measures.
“Worldwide, but especially in the United States, many physicians are still not aware of axial spondyloarthritis, and it is our duty to ensure that patients with chronic back pain are not diagnosed with a disease that they do not have,” Robert B.M. Landewé, MD, PhD, professor of rheumatology at the University of Amsterdam in the Netherlands, said during a press conference.
“Rheumatologists in the United States focus on rheumatoid arthritis and do not see too many patients with chronic back pain,” he said. “Although this is entirely an inflammatory rheumatological condition, these patients are often treated by physical therapists and orthopedists. More importantly, they usually do not receive the best treatment for their condition.”
To determine the specificity of MRI scans of sacroiliac joints, Landewé and colleagues compared the MRI scans of 47 patients with axial spondyloarthritis against cohorts of 47 age- and gender-matched healthy individuals, 47 patients with chronic back pain, seven women with postpartum back pain for several months and 24 frequent runners.
Researchers assigned three blinded readers to randomly score the MRI scans according to the assessment of spondyloarthritis (ASAS)/outcome measures in rheumatology (OMERACT) and the Spondyloarthritis Research Consortium of Canada (SPARCC) definitions.
According to study results, the readers agreed in 75.6% to 79.9% of cases on the presence or absence of bone marrow edema, correlated by their SPARCC scores. Among healthy individuals, 23% exhibited a positive sacroiliac MRI compared with 87% of patients with axial spondyloarthritis, 6% of patients with chronic back pain, 12% of frequent runners and 57% of women with postpartum back pain.
Landewé and colleagues observed that mean SPARCC scores were 1.7 for the healthy individuals, 20.9 for patients with axial spondyloarthritis, 0.8 for the chronic back pain patients, 4.5 for the women with postpartum back pain and 0.8 for the frequent runners.
When a SPARCC score of two or higher was used as a cut-off for positivity, researchers found 25% of healthy individuals, 97% of patients with axial spondyloarthritis, 10% of patients with chronic back pain, 16% of runners and 57% of women with post-partum back pain were declared positive. In addition, when a SPARCC score of five or greater was used, only 14% of healthy individuals, 87% of patients with axial spondyloarthritis, 2% of patients with chronic back pain, 28% of women with postpartum back pain and no runners were positive.
While deep bone marrow edema lesions were not found among healthy individuals, patients with chronic back pain or frequent runners, lesions were observed in 80% of patients with axial spondyloarthritis and 14% of women with post-partum back pain.
“If you don’t know the disease very well or if you have too little experience making a diagnosis of axial spondyloarthritis, then you easily inclined to use a diagnostic test, such as MRI, for the wrong reasons,” Landewé said. “We need your help to make sure that the doctors in the United States are aware of axial spondyloarthritis, and that they need a little bit more expertise in diagnosing this disease.”-by Bob Stott
de Winter J, et al. Abstract 1831. Presented at: American College of Rheumatology Annual Meeting; Nov. 4-8, 2017; San Diego.
Disclosures: Landewé is a member of the Assessment in SpondyloArthritis International Society. Please see the full study for a complete list of all other authors’ relevant financial disclosures.