Axial spondyloarthritis: synthetic magnetic resonance imaging in the detection of sacroiliac joint lesions

Abstract

To the Editor: Axial spondyloarthritis (axSpA) is characterized by sacroiliac joint inflammation, spine inflammation, bone destruction, and osteogenesis. Ankylosis of the spine and/or hip joints may occur later, significantly affecting the patient's quality of life. As the earliest and most common imaging finding of axSpA, sacroiliitis can be divided into early active and late structural lesions. Magnetic resonance imaging (MRI) not only detects active inflammatory changes that cannot be found in computed tomography (CT) or X-rays but also has a similar sensitivity to CT in detecting structural lesions. [1] However, conventional MRI only provides the qualitative diagnosis of sacroiliac joint lesions but does not provide quantitative information. Objective, accurate, and repeatable quantitative assessment, especially for bone marrow edema (BME) and fat metaplasia, which are associated with disease prognosis, offers potential imaging methods to evaluate the state of illness and therapy efficacy. Synthetic MRI, as a new imaging technique, provides both qualitative and quantitative information based on the same scan. In the present study, we aimed to verify whether synthetic MRI provides the similar qualitative diagnostic value of sacroiliac joint lesions in patients with axSpA compared with conventional MRI and to assess the quantitative diagnostic performance of quantitative maps generated by synthetic MRI in the detection of BME and fat metaplasia in the sacroiliac joint. To our knowledge, this study is the first to investigate the potential practicality of synthetic MRI for assessing sacroiliac joint lesions in participants with axSpA.Ke Zhang and Jing Zheng contributed equally to the work.