Magnetic resonance imaging in spondyloarthritis – how to quantify findings and measure response




Sensitive and reliable tools for monitoring disease activity and damage, and for prognostication, are essential in the management of patients with spondyloarthritis, including ankylosing spondylitis and psoriatic arthritis.


Magnetic resonance imaging (MRI) allows direct visualisation of inflammation in peripheral and axial joints, and peripheral and axial entheses, and has dramatically improved the possibilities for early diagnosis and objective monitoring of the disease process in spondyloarthritis. Truthful, discriminative and feasible scoring systems are available for the assessment of inflammatory activity in the spine and sacroiliac joints in axial spondyloarthritis and in the hands of patients with peripheral psoriatic arthritis. Various systems for assessment of damage in axial and peripheral joints are available, but further studies are needed to document their value in clinical trials and clinical practice.


The present article reviews key aspects of the status and recent important advances in MRI in spondyloarthritis, focussing on available MRI tools for assessing activity and damage in peripheral and, particularly, axial joints.


Magnetic resonance imaging (MRI) allows direct visualisation of the abnormalities in peripheral and axial joints and entheses that occur in ankylosing spondylitis (AS), psoriatic arthritis (PsA) and other forms of spondyloarthritis (SpA). MRI has resulted in a major improvement in the evaluation and management of patients with SpA. First, it permits earlier diagnosis . Diagnosis was previously dependent on the presence of bilateral moderate or unilateral severe radiographic sacroiliitis, as part of the modified New York criteria for AS . This frequently delayed the diagnosis by 7–10 years . Second, MRI can provide objective evidence of currently active inflammation in patients with SpA . Until the introduction of MRI, disease activity assessment was restricted to patient-reported outcomes, such as the Bath ankylosing spondylitis disease activity index (BASDAI) and functional index (BASFI) , because disease activity could not be assessed in a sensitive manner by biochemical (mainly C-reactive protein (CRP)) or physical evaluation .


Inevitably, these abilities of MRI have led to a large interest in developing and testing MRI tools for measuring inflammatory activity in SpA, which could be used for monitoring disease activity in clinical trials of new therapeutics and in clinical practice, and, if possible, would allow prediction of treatment response and future disease course.


The present article will describe the main pathologies that can be visualised by MRI and then focus on available MRI-based assessment systems for assessing inflammation and damage in peripheral and, particularly, axial joints in SpA.


What can be visualised


The spondyloarthritides have traditionally been divided into AS, PsA, enteropathic arthritis, reactive arthritis and undifferentiated SpA . AS, which is thought to be the most common and most typical form of SpA, is dominated by axial disease manifestations in the spine and sacroiliac joints, and clinical assessment systems have focussed on quantitating axial disease , as has subsequently the development of MRI assessment tools . By contrast, PsA most frequently is dominated by peripheral manifestations, although axial disease occurs in a substantial proportion of patients, and clinical assessment systems, for example, the composite PsA response criteria (PsARC), have focussed on peripheral disease . Similarly, a recently developed MRI scoring system for PsA focusses on peripheral disease .


MRI is, through its ability to detect inflammatory changes in bone and soft tissues, the most sensitive imaging modality for recognising early spine and sacroiliac joint changes in AS. MRI findings indicating active disease in the sacroiliac joints (sacroiliitis) include juxta-articular bone marrow edema, and enhancement of the bone marrow and the joint space after contrast medium administration ( Figs. 1 and 2 ), while visible chronic changes include bone erosions, sclerosis, periarticular fatty tissue accumulation, bone spurs and ankylosis ( Fig. 3 ). Typical lesions of the spine, which indicate active disease, are spondylitis ( Fig. 4 ), spondylodiscitis and arthritis of the facet, costovertebral and costotransverse joints. Chronic changes including bone erosions, focal fat infiltration, bone spurs and/or ankylosis frequently occur ( Figs. 5–7 ). Enthesitis is also common, and may affect the interspinal and supraspinal ligaments and the interosseous ligaments in the retro-articular space of the sacroiliac joints. Some patients also have disease manifestations in peripheral joints and entheses, and these can be visualised by MRI as in other diseases .




Fig. 1


Active inflammatory lesions in the sacroiliac joints . Extensive bone marrow edema (arrows) bilaterally in the sacral and iliac bones, documenting active sacroiliitis. Semicoronal STIR (A) and T1-weighted (B) MR-images.

Nov 11, 2017 | Posted by in RHEUMATOLOGY | Comments Off on Magnetic resonance imaging in spondyloarthritis – how to quantify findings and measure response

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