Combining data from X-rays and magnetic resonance imaging (MRI) scans may lead to earlier detection of spondyloarthritides in patients presenting with recent-onset inflammatory back pain, according to new research published in an online edition of the Annals of Rheumatic Diseases.¹

According to the findings, conventional X-rays can detect structural changes in sacroiliac (SI) joints with higher sensitivity than MRIs, but inflammation on MRIs can be found in a substantial proportion of patients with inflammatory back pain and normal radiographs.

"At the moment most rheumatologists use only radiographs," lead researcher Désirée van der Heijde, MD, professor of rheumatology at University Hospital Maastricht in the Netherlands, tells CIAOMed. "Our data show that in patients without changes on the radiographs but a clinical picture suspicious for spondyloarthritides/ankylosing spondylitis (SpA/AS), it is useful to add MRI.

"Whether earlier diagnosis and earlier treatment with TNF inhibitors will stop the disease from progressing is unknown, as we don't have data on the use of TNF blockers in such early cases," Dr. van der Heijde says. "But this is indeed what we expect: early diagnosis with early treatment of TNF blockade in patients with high risk of progressive disease, prevention of permanent disability, and ability to remain in a paid job. Our advice [to combine] imaging modalities leads to an earlier diagnosis with [these] possible consequences."

The new data "are valid for patients with recent-onset inflammatory back pain with a high suspicion of SpA [who are] seen by a rheumatologist, [but] whether the results are also generalizable to patients with a lower likelihood of SpA is not known," the researchers conclude.  While the radiograph/MRI combination can lead to earlier diagnosis, the additional screening measures also result in additional costs that must be taken into consideration, Dr. van der Heijde says.

In the study, 68 patients with inflammatory back pain for up to 2 years underwent MRI scans of the SI joints. Scans were scored for inflammation and structural changes. Conventional pelvic radiographs were scored according to the modified New York grading. Researchers analyzed agreement between MRI and X-ray by cross-tabulation per SI joint and per patient.

They found that assessment of structural changes by X-ray followed by assessment of inflammation on MRI in patients with negative findings gives the highest returns in terms of detecting involvement of the SI joints by imaging in patients with recent-onset inflammatory back pain. 

"The data add to the hypothesis that inflammation comes first and structural changes are a subsequent feature," the researchers report. "Depending on the lag time between inflammation and structural changes, a diagnosis of sacroiliitis could be made importantly earlier by using MRI inflammation as an early sign of disease." Follow-up studies are currently underway.

Reference

1. Heuft-Dorenbosch L, Landewé R, Weijers R, et al. Combining information obtained from MRI and conventional radiographs in order to detect sacroiliitis in patients with recent-onset inflammatory back pain. Ann Rheum Dis [serial online]. October 11, 2005.