Dr. Maksymowych has been an international leader on the use of MRI in radiographic spondyloarthropathy (SpA). On Friday morning, he presented data from SASPIC, a collaborative research initiative of rheumatologists in Canada.
As we all know, inflammatory back pain is often difficult to differentiate from mechanical low back pain. Furthermore, objective diagnostic tools are limited and plain x-rays have low sensitivity and reliability. Traditionally, this hasn't mattered as treatment options for SpA were limited. With the advent of new therapies and a focus on early treatment, there has been a shift towards early referral and diagnosis.
The objective of this study was to facilitate earlier diagnosis of SpA from the G.O.D. specialists (gastroenterologists, ophthalmologists and dermatologists) and to develop specific referral criteria for low back pain. The participating rheumatologists agreed to facilitate rapid assessment of patients under 45 years of age with undiagnosed chronic back pain of at least 3 months duration from G.O.D. specialists. All of these patients had SpA associated conditions including colitis, uveitis, and psoriasis. The rheumatologists evaluated the patients clinically, and scored the likelihood of SpA (1-10). The patients were then sent for bloodwork and plain films and the likelihood of SpA was scored again (1-10). Finally, at the discretion of the rheumatologist, patients were referred for MRI and given a third score for SpA (1-10).
In total, 106 patients were seen, with average symptom duration of 7 years. After clinical evaluation only, 62% were classified with SpA. This was modified to 57% once lab and plain film data were incorporated and to 36% with the addition of MRI information. The addition of MRI information resulted in disease reclassification more frequently than plain films. Although there is a cost to adding MRI in the assessment algorithm for SpA, it may result in reduction of medication costs if it leads to reclassification and minimizes over-diagnosis.
The results of this study are very interesting, but more work is needed. As was asked by Dr. Nigil Haroon, does a normal MRI rule out SpA? If a patient has inflammatory low back pain with clear sacroilitis on plain film but a normal MRI, can we say that they don't have a spondyloarthropathy? What about those without SI joint involvement? We need to be careful. MRI is another tool to help us clinically manage patients, but we should not use it independently of our own clinical judgement.
Dr. Jamal is a Clinical Associate Professor at the University of British Columbia and an active staff physician at Vancouver Coastal Health. Her interests include diagnosis and prognosis of early inflammatory arthritis, and timely assessment and access to care for patients with rheumatoid arthritis.View Full Bio