[Sacroiliitis:the key symptom of spondylarthropathies. 2: morphological aspects].

Because of their curved course and segmental convolution of articular surfaces, the anatomy of the sacroiliac joints is complex. An important part of the diagnosis of sacroiliitis of spondyloarthropathy patients relies on radiographic imaging techniques: x-ray, conventional tomography, computed tomography (CT) and scintigraphy. Diagnosis can be difficult in early and acute stages of sacroiliitis because radiographic findings may be normal, although dynamic magnetic resonance imaging (MRI) of the sacroiliac joints certainly enables to detect chronic as well as acute inflammatory changes. In spondyloarthropathy patients with acute sacroiliitis or acute exacerbation of chronic sacroiliitis who do not respond to or do not tolerate non-steroidal antiinflammatory drugs, CT-guided corticosteroid injection into the sacroiliac joints has proved to be an effective therapy.