In this workshop, Dr. Marie-Josée Berthiaume, a bone radiologist from Maisonneuve-Rosemont Hospital in Montreal, reviewed how new imaging outcomes have improved the diagnosis and follow-up of spondyloarthritis and the assessment of therapeutic modalities.
Imaging in SpA can be used for initial diagnosis, follow-up and evaluation of complications including pseudoarthrosis and fractures. The types of imaging available include plain films, ultrasound (not useful for spine), MRI, CT scan, bone scintigraphy and PET scans. The latter two are sensitive but not specific, and thus not used very much.
Although plain films are cheap and safe, they are often normal in early disease and do not allow us to distinguish active inflammation from longstanding disease. CT scans are excellent for showing erosions and fractures, but do not give us information on active inflammation. Furthermore, they are associated with high doses of radiation.
MRI (STIR or gadolinium-enhanced views) can show pre-erosive edema in bones (including Romanus and Anderson lesions), entheseal sites and ligaments, making them ideal for early diagnosis. Many of these lesions are not seen on plain film until later. They can also be used to evaluate acute or chronic inflammation in patients with longstanding disease who have abnormal plain films. This can help distinguish back pain due to damage from that due to active inflammation.
With the advent of MRI, we have learned that changes can be seen at the costovertebral level (T9-12) prior to the development of sacroiliitis. As a result, Dr. Berthiaume recommends the following MRI series when evaluating a person with spondyloarthropathy. This sequence takes approximately 45 minutes and involves no radiation.
T-L junction (58% positivity). T9-01, T12-L1
Entire spine (2 segments) – four sequences
Sagittal SET1 and TSET2 fat sat at cervicothoracic and thoracolumbar levels (4)
Axial TSET2 fat sat at T9-12 to evaluate costovertebral joints
Axial oblique and coronal oblique at SI joints in SET1 and STIR
MRI should have SET2 fat sat or STIR sequences to detect acute or active inflammatory changes. Gadolinium is costly and likely not necessary. Furthermore, there is a small risk of gadolinium-induced skin fibrosis. MRI scoring can be used for research purposes but may not be necessary in clinical practice.
Experienced readers are necessary for interpretation of films, detection of complications (such as fracture and pseudoarthrosis) and to exclude mimickers of spondyloarthropathy.
Despite the fact that MRI is arguably the new gold standard in SpA, access (both to the test itself and to expert radiologists) remains a significant barrier to use.
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