More Than Meets the Eye

Although this type of thinking is often characteristic of what occurs in clinical practice, Dr. Hwang noted that clinical reasoning is a constant, iterative process, one that requires an ongoing refinement of our understanding of each disease and an analysis of our clinical capabilities.

Imaging

Dr. Gensler

The second speaker in the session was Lianne Gensler, MD, professor of medicine, director, Ankylosing Spondylitis Clinic, University of California, San Francisco. She described the role of imaging in the diagnosis of nr-axSpa.

To start her talk, Dr. Gensler paraphrased the shoe company Nike: if you are thinking about pursuing SI joint imaging based on your clinical assessment, just do it. She noted that imaging is but one piece of the puzzle, but it is a helpful data point because physical exam findings can be hard to detect in patients with nr-axSpA.

Many other features of the condition are non-specific, and there are potential mimics of the disease, thus imaging can help clarify the clinical impression of a provider. In essence, just as a rheumatologist would pursue a temporal artery biopsy for a patient suspected of having giant cell arteritis, so too should they pursue imaging when features of inflammatory back pain are present.

Dr. Gensler explained that imaging in axSpA can be helpful both for diagnosis and for evaluating the effects of treatment/disease progression. Conventional radiographs remain the first-line imaging study, although they generally have poor sensitivity and specificity.

MRI of the pelvis or sacrum would be the next best test to pursue when radiographs are negative but clinical suspicion for axSpA remains high. The MRI does not require contrast and, specifically, the T1 sequence can be helpful in evaluating structural changes and the STIR/T2 fat suppressed sequence can be helpful in evaluating inflammatory changes.

In addition, low-dose computed tomography studies of the pelvis may also be helpful and are widely available.

Dr. Gensler observed that ordering and arranging for the correct imaging for patients can be complicated in terms of logistics. Further, even when the correct imaging protocols are used, there is variability among radiologists in their familiarity with axSpA and their ability to read these studies well. Ideally, a discussion between the rheumatologist and the radiologist should take place to help ensure a mutual understanding of imaging findings.

In the future, artificial intelligence may be able to assist in detecting subtle inflammatory changes and could serve as a proxy for an expert radiologist in geographic areas where such experts are not available.