Inflammatory Arthritis of the Spine

Spondyloarthritis is a group of diseases that cause inflammatory arthritis of the spine, sacroiliac joints, and peripheral joints. This group includes ankylosing spondylitis, psoriatic arthritis, arthritis associated with inflammatory bowel disease, reactive arthritis, undifferentiated spondyloarthritis, and juvenile spondyloarthritis. Imaging of the sacroiliac joints and spine is crucial for the diagnosis of axial spondyloarthritis. Imaging of the sacroiliac joints is included in the classification criteria of axial spondyloarthritis. Radiographs have been used for decades to image chronic changes in the sacroiliac joints and spine. CT is sensitive for demonstrating initial bone erosions and sclerosis. MR imaging is superior in detecting early inflammatory changes in bone and soft tissue. This review article summarizes features of various subtypes of spondyloarthropathies, including their complications, and provides a brief review of potential differential diagnoses.Learning Objectives: To identify key imaging features of spondyloarthritis, including complications, and recognize top differential considerations.