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Lesions on MRI absent symptoms, history may yield false spondyloarthritis diagnosis
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SAN DIEGO – A physical exam and complete medical history should supplement MRI results when making a diagnosis of spondyloarthritis, according to findings presented at the ACR Annual Meeting.
Study results from Thomas Renson, MD, a researcher and PhD student at Ghent University in Belgium, and colleagues revealed a “markedly high prevalence” of bone marrow edema and structural lesions among young, active patients. While the lesions mimicked spondyloarthritis, no participants had been diagnosed with the condition. The findings underscore the importance evaluating an MRI in the context of the entire clinical picture to accurately diagnosis the condition, Renson told Healio Rheumatology.
“The patients in our study had no symptoms, such as back pain. They were healthy military recruits,” he said. “The lesions were rather limited – no recruits had MRI findings that showed full-blown spondyloarthritis – but were similar to spondyloarthritis lesions. It was quite interesting.”
Gaëlle Varkas, a PhD student at Ghent University, and colleagues performed MRIs of the sacroiliac joints on 22 military recruits. The MRIs were conducted before and after 6 weeks of physical training. Bone marrow edema and structural lesions were analyzed by three trained readers who were blinded to time classifications and clinical results.
The researchers used Spondyloarthritis Research Consortium of Canada criteria to evaluate bone marrow edema and an adjusted version of the Spondyloarthritis Research Consortium of Canada criteria to examine structural lesions. Sclerosis, erosions, fatty lesions and ankylosis “were scored per quadrant on 6 consecutive slices representing the cartilaginous part of the joint,” according to the study results. In addition, the readers agreed on the definition of a positive MRI as determined by Assessment of Spondyloarthritis International Society criteria and evaluated that as one of the outcome measures.
Nearly half of the recruits evaluated (n = 9; 40.9%) had existing bone marrow edema lesions at baseline. By Week 6, fully half of the patients (n = 11) presented with such lesions (P = .625). The mean number of lesions was 2.4 (± 0.4) at baseline and 3.7 (± 1.3) at Week 6. The mean change in lesions among all recruits was 0.9 (± 0.6; P = .109). In addition, the number of recruits with a positive MRI as assessed by ASAS criteria increased from baseline to Week 6 (22.7% vs. 36.4%; P = .375).
Structural lesions were noted in 36.4% (n = 8) of recruits at baseline. By Week 6, half of the recruits had such lesions (50%; P = .453).
A substantial increase in the number of lesions was observed over time when the number of structural and inflammatory lesions was combined (P = .038).
“There are a couple of possible reasons for the lack of statistical significance,” Renson said during a press conference. “First, it’s a small study. In addition, the recruits were very well-trained before starting the trial; they were chosen based on their physical abilities. It could be that additional mechanical stress caused by the training did not make a difference when evaluated against the overall impact the body had already endured and could explain the high prevalence of lesions at baseline.”
The results underscore the importance of a complete physical exam and a full medical history in addition to an MRI when diagnosing spondyloarthritis, Renson told Healio Rheumatology.
“The MRI is a good tool for the diagnosis of spondyloarthritis, but you cannot use an MRI alone,” he said. “It’s like all diagnostic tools. If you do a lot of tests on a perfectly healthy person, without reason to think there’s a problem, you will always find something. It’s the same with an MRI of the sacroiliac joints.”
He also highlighted the kind of information that would warrant suspicion of spondyloarthritis and the impact of these observations on diagnosis.
“This trial underscores the importance of interpreting imaging in the right clinical context. If you have a patient with inflammatory back pain, you have to ask questions,” Renson said. “Is there rheumatoid arthritis in the family? Does the pain get better with NSAIDs? Incorrect interpretation of the clinical context may lead to a wrong diagnosis of spondyloarthritis in a young, active cohort of patients.” – by Julia Ernst, MS
Reference:
Varkas G, et al. Abstract 253. Presented at: ACR Annual Meeting; Nov. 3-8, 2017; San Diego.
Disclosures: Varkas reports no relevant financial disclosures. Please see the full study for a list of all other researchers’ relevant financial disclosures.