Back to the roots of rheumatology - Imaging of regional pain syndromes.

Musculoskeletal regional pain syndromes (RPS) often lead to patient referrals in general and rheumatological practice. Detailed history taking and clinical examination can, in most cases, reveal the cause for pain and direct the subsequent management of the conditions. Yet, when in doubt, imaging methods, such as ultrasound (US) may support the clinical assessment. This paper reviews the underlying pathologies of some of the most frequently encountered RPS and the role of musculoskeletal US imaging for their diagnosis and treatment. If available, data on diagnostic accuracy and comparisons with gold standards are reported. The article stresses the importance of anatomical and sonoanatomical knowledge for the proper interpretation of the US images, points out the advantages and disadvantages of this imaging tool, and suggests the future research agenda.