1. To become familiar with the current diagnostic concepts in the imaging of arthritis.
2. To understand the pathology of arthritis and its imaging phenotypes.
3. To appreciate the value of radiography, ultrasound and MRI.
The current diagnostic concept is to embed imaging in the assessment systems in rheumatology. This means that imaging should contribute to the detection of early arthritis and to the quantification of abnormalities with prognostic impact. With the combinations of joint pain, laboratory indicators of inflammation and imaging features of tendovaginitis, joint effusion and/or bone marrow inflammation subforms of early arthritis may be defined. Synovitis is today regarded as part of a systemic autoimmunologic disease, and certain phenotypes can be classified with relation to the fibroblastic response and different interleukin expression leading to a destructive-erosive, a sclerotic-proliferative or a mixed imaging appearance. With US and radiography, followed by MRI, the patterns of arthritis and their differentiation from normal anatomic structures can be assessed and displayed in dedicated structured reporting templates. The differential diagnosis of autoimmune-mediated arthritis includes crystal-induced arthropathies, erosive osteoarthritis, posttraumatic and other forms of secondary joint inflammation.