Recognize the clinical, laboratory and genetic features that characterize seronegative spondylarthropathies; Recognize the presence of subtle imaging findings that characterize seronegative spondylarthropathies to make an accurate early diagnosis Describe the imaging features of seronegative spondylarthropathies on magnetic resonance imaging (MRI).

Seronegative spondyloarthropathies are a group of musculoskeletal diseases with clinical, laboratory and genetic features in common. They affect the axial skeleton, are positive to HLAB27 gene and negative to rheumatoid factor. This entity (spondyloarthritis) can be divided in five subgroups: Ankylosing spondylitis; Reactive arthritis (Reiter syndrome); Psoriatic arthritis; Arthritis associated with inflammatory bowel disease (Crohn disease or ulcerative colitis); Undifferentiated spondyloarthritis. They affect both genders but are more frequent in men and usually start between the second and the fourth decades of life. Clinical presentation...

Until recently, the definitive diagnosis of spondyloarthritis (SpA) relied on conventional radiography. Studies have compared MR imaging and conventional radiography revealing strengths and weaknesses of both modalities. Results suggested that syndesmophytes are better depicted with conventional radiography; ankylosis, equally well with both imaging techniques; and all other lesions, better with MR imaging. Thus, MRI is a more sensitive method to depict the characteristic findings of spondylarthropathies. Furthermore, radiographic changes usually develop at least 5 years after symptom onset. In fact, for many years, the diagnose...

MRI is considered the most sensitive imaging method for detecting the first signs of arthritis (not apparent with the conventional radiographic studies). Radiologists should be familiar with MRI findings evocative of spondyloarthritis and its differential diagnosis in order to suggest an accurate diagnosis that can lead to an expensive, but effective treatment option (biologic therapy, like TNF alfa inhibitors), if the disease is diagnosed before structural damage occur.

F.N. Boy et al.; The role of multi-parametric MR imaging in the detection of early inflammatory sacroiliitis according to ASAS criteria; European Journal of Radiology 83 (2014) 989–996 Kay-Geert A. Hermann; et al.; Spinal Changes in Patients with Spondyloarthritis: Comparison of MR Imaging and Radiographic Appearances; RadioGraphics 2005; 25:559 –570 Clarissa Canella; et al.; MRI in Seronegative Spondyloarthritis: Imaging Features and Differential Diagnosis in the Spine and Sacroiliac Joints; AJR 2013; 200:149–157 Fatma Nur Boy, et al.; The role of multi-parametric MR imaging in the...

Ana Catarina Vieira Radiologist in training at Hospital do Espírito Santo de Évora Portugal Contact: [email protected]