[Concept and understanding of non-radiographic axial spondyloarthritis]

Since the publication of the classification criteria for axial spondyloarthritis (axSpA) by Assessment of SpondyloArthritis international Society (ASAS), a new disease concept "non-radiographic axial spondyloarthritis (nr-axSpA)" has emerged. Some domestic experts in China have translated it as "radiologically negative" axSpA, but it can easily lead to misunderstandings literally, as not all patients with nr-axSpA are completely free from radiological abnormalities. This article briefly describes the evolution of the concept of axSpA, proposes to translate the term of nr-axSpA directly rather than "radiologically negative" axSpA, compares the differences and similarities between nr-axSpA and radiologically negative axSpA, delineates the relationship between nr-axSpA and early ankylosing spondylitis, and points out not all the patients who meet the ASAS classification criteria for nr-axSpA are genuine patients with axSpA, because of the relatively low specificity of the ASAS classification criteria. Five common scenarios easily leading to misdiagnosis of nr-axSpA are exampled to remind domestic colleagues.