About this Research Topic
Rheumatoid arthritis (RA) prognosis is conditioned by functional handicap which is closely linked to joint damage. Early initiation of treatment is associated with a better outcome and less structural damage. Therefore, identifying RA at the very early stages of the disease, before clinical arthritis, is of high interest and several imaging are being evaluated to determine individuals at-risk of RA.
Recently, the important role of magnetic resonance imaging (MRI) has emerged in the differential diagnosis of unclassified early arthritis and is now recommended in litigious cases when RA diagnosis is still uncertain.
Typical imaging findings in patients with axial spondyloarthritis (axSpA) show first inflammatory and later increasingly rather osteoproliferative than osteodestructive changes both in the sacroiliac joints (SIG) and the spine. While the former are mainly detectable by magnetic resonance imaging (MRI), structural changes are better displayed by conventional X-rays and computer tomography (CT).
In axSpA, sacroiliitis, spondylitis, abacterial spondylodiscitis and inflammatory changes of the zygoapophyseal joints are the most important inflammatory manifestations in the axial skeleton. However, the incidence and prevalence of such changes as well as the occurrence and severity of structural damage are quite different. The classification into radiographic (r-) and non-radiographic (nr-) axSpA is based on the ASAS classification criteria of 2009, however, in daily routine practice, diagnosis is made by the discretion of the treating physician without differentiation into different stages.
The exact pathogenesis and, in particular, the complex process or relationship between inflammation and the development of structural changes is still insufficiently understood.
The effect of anti-inflammatory drugs such as non-steroidal anti-inflammatory drugs (NSAIDs) or biological disease-modifying drugs (bDMARDs) on bone marrow edema on MRI or X-ray progression in the axial skeleton are relevant both for individual patients in daily care and as objective outcomes in clinical studies with axSpA patients.
Psoriatic arthritis (PsA), a heterogeneous multifactorial disease with mainly musculoskeletal involvement, may manifest as mono-, oligo- or polyarthritis and may also affect the axial skeleton in some patients. The most common signs of inflammation are bone marrow edema and enthesitis. The early and differential diagnosis of PsA represents a clinical challenge, especially as a differential diagnosis to other inflammatory or degenerative joint diseases. Through the use of magnetic resonance imaging (MRI), musculoskeletal sonography (US) and fluorescence optical imaging (FOI), inflammatory joint and tendon changes in the extremities and spine can be visualized with high sensitivity. MRI has a prognostic value, especially at the beginning of the disease, with regard to the further radiographic course of the disease.
Through the use of computer tomography (CT) and conventional x-ray imaging, structural damage can be specifically and in part three-dimensionally depicted in the peripheral joints and the spine. In particular, high-resolution CT (HR-pQCT) can map pathophysiological processes and their morphological effects at an early stage of the disease.
The contributions to this topic should cover all indications for imaging and imaging techniques and will provide an overview of the advantages and limitations of imaging with a special focus on its potential role in inflammatory-rheumatic diseases.
Keywords: Imaging, rheumatoid arthritis, spondyloarthritis, psoriatic arthritis, vasculitis, Polymyalgia rheumatica, Osteoarthritis, Therapeutic management
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