Top-Ten Tips for Effective Imaging of Axial Spondyloarthritis

Abstract

Axial spondyloarthritis (axSpA) is a chronic inflammatory condition that encompasses ankylosing spondylitis as well as nonradiographic axSpA and can lead to chronic pain, structural damage, and disability. The disease is strongly associated with the presence of human leukocyte antigen-B27. Early diagnosis of axSpA is significant due to new treatment regimens leading to reduction of inflammation and potentially delaying disease progression. Imaging of the sacroiliac joints and the spine plays an important role in the early diagnosis of spondyloarthritis. In the current review, the top-ten tips for the effective imaging of axSpA are presented to help both radiologists and rheumatologists in using imaging properly and effectively in their clinical practice.

Axial Skeleton Bone Marrow Changes in Inflammatory Rheumatologic Disorders

“…23,24 Early treatment decreases pain and stiffness and also prevents structural damage over time, under investigation by the Assessment in SpondyloArthritis international Society (ASAS) and others. 21 The axial skeleton is the focus of this article, and AS is the prototype of axSpA, discussed here. The incidence peaks between 20 and 40 years, evenly divided between male and female patients.…”

“…In the spine, the earliest inflammatory sign is BME, typically at the site of the enthesis. 21,29,30 Inflammation of tendon and ligamentous insertions leads to a cascade of secondary changes in soft tissue and bone. 31 On radiographs of the spine, for example, chronic changes associated with enthesitis can be detected as erosions, paravertebral ossifications (syndesmophytes) with ankylosis as an end stage.…”

“…Sacroiliitis is the hallmark of axSpA. The imaging parts of SI joint involvement are divided into active inflammatory lesions and structural (chronic) changes, 21,34 and SI involvement can present as asymmetric and unilateral SI inflammation in early disease, all the way to bilateral ankylosis.…”

“…34 The diagnosis of axSpA should not rely on isolated findings such as single and small (< 1 cm) BME lesions, only seen on one slice and without associated structural findings in the SI joints (e.g., erosions, subchondral sclerosis, or fatty lesions). 21,35…”

“…In addition, extra-articular expression of inflammation may be present in the skin (psoriasis), bowel, and uvea. 21 To characterize these patients, two groups are defined: one with a dominant involvement of the spine and SI joints called axial spondyloarthritis (axSpA) and another with a preference for peripheral joint inflammation called peripheral SpA. 22 This classification into axial and peripheral SpA helps with earlier detection of patients with inflammatory back pain and early treatment options.…”