This article presents the recommendations of the European Society of Musculoskeletal Radiology Arthritis Subcommittee regarding the standards of the use of MRI in the diagnosis of musculoskeletal rheumatic diseases. The recommendations discuss (1) the role of MRI in current classification criteria of musculoskeletal rheumatic diseases (including early diagnosis of inflammation, disease follow-up, and identification of disease complications); (2) the impact of MRI on the diagnosis of axial and peripheral spondyloarthritis, rheumatoid arthritis, and juvenile spondyloarthritis; (3) MRI protocols for the axial and peripheral joints; (4) MRI interpretation and reporting for axial and peripheral joints; and finally, (5) methods for assessing MR images including quantitative, semiquantitative, and dynamic contrast-enhanced MRI studies.

The syndromes synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) and chronic recurrent multifocal osteomyelitis (CRMO) constitute a group of chronic relapsing inflammatory osteoarticular disorders with frequently associated skin eruptions such as palmoplantar pustulosis and acne conglobata and rather characteristic imaging features in the form of osteitis and/or hyperostosis. CRMO predominantly occurs in children/adolescents and SAPHO in adults. Any skeletal site can be involved, and the imaging appearances vary, depending on the patient's age and the stage/age of the lesion. The diagnosis may be difficult if there is no skin disease, but attention to characteristic imaging appearances may help avoid misdiagnosis (e.g., infection and tumor) and thereby unnecessary invasive procedures as well as facilitating early diagnosis and appropriate treatment. This article provides an overview of the radiologic appearances of SAPHO/CRMO and relevant pathogenetic, clinical, and pathologic features to facilitate the diagnosis that often requires an interdisciplinary approach including radiologists.