[Imaging procedures in rheumatology. Differential diagnosis using various imaging procedures in rheumatoid arthritis (RA)].

Conventional radiography, ultrasonography (US), magnetic resonance imaging (MRI), computed tomography, and scintigraphy are imaging techniques in use for rheumatoid arthritis (RA). Conventional radiography of the hands and the forefeet should be performed every 6 to 12 months in the first two years, and every 12 to 24 months after two years, in search of erosions. If radiography fails to detect erosions, radiography using a second plane should be done. US or MRI may be used to detect earlier erosions if therapeutic consequences exist. In severe RA, radiography of the cervical spine in the neutral position and with inclination should be performed every 3 to 4 years. MRI should be done, if the distance between atlas and dens is >4 mm. Scintigraphy is indicated if arthralgia occurs in many joints. US may detect or exclude inflammatory changes if arthralgia occurs in a few joints. Single symptomatic joints may be assessed by US to differentiate pathologies. Radiography aids in establishing a differential diagnosis, e. g., to detect osteoarthritis. MRI is indicated if the radiography or US is equivocal. It is indicated to diagnose osteonecrosis or meniscal lesions. Arthrocenthesis may be done without imaging or under radiographic or sonographic guidance.