We aim to outline a pictorial review of MRI imaging in seronegative spondyloarthropathy, including familiarising the reader with the inflammatory arthritis protocol, demonstrating the imaging findings used in the diagnosis of acute and chronic seronegative spondyloarthropathy, and illustrating some incidental/non-arthropathic findings encountered in imaging.

The term spondyloarthritis refers to a group of systemic conditions characterised by a range of clinical manifestations, laboratory and imaging features, with strong association to the HLA B27 gene [1]. The spectrum of spondyloarthritis includes ankylosing spondylitis, psoriatic arthritis, arthritis related to inflammatory bowel disease, reactive arthritis and undifferentiated arthritis. Skeletal involvement may be axial, typically involving the sacroiliac joints and the spine, whilst peripheral involvement may include dactylitis, enthesitis, and oligo/monoarthritis. Typical extra- articular manifestations include uveitis, psoriasis and inflammatory bowel disease [2]. Diagnosis...

MRI is considered the most sensitive modality for detecting inflammatory changes in the initial diagnosis of seronegative arthropathy. At our institution we have incorporated imaging of the spine, thorax, pelvis and sacroiliac joints into an 'inflammatory spine' protocol, we utilise the protocol in practice to assess disease activity, monitor and evaluate therapeutic response. The sequences and MRI parameters utilised in our trust are as follows: Sequence TR (ms) TE (ms) TI (ms) Sagittal STIR whole spine 4000 48 220 Sagittal T1 whole spine 400 9.1...

With the increasing use of MRI in assessment of spondyloarthropathy, it is vital that reporting radiologists familiarise themselves with the sequences, protocols, typical MRI features of arthropathy, as well as some possible incidental/ non-arthopathic findings that may require further imaging or investigation.

P. Eneje; Stevenage/UK - nothing to disclose J. Ryan; Stevenage/UK - nothing to disclose B. Annan; Stevenage/UK - nothing to disclose

[1] Paul Bowness. HLA B-27. Annual Review of Immunology 2015 33:1, 29-48 [2] Mitulescu TC, Popescu C, Naie A, et al. Acute anterior uveitis and other extra-articular manifestations of spondyloarthritis. J Med Life. 2015;8(3):319–325. [3] National Institute for Health and Care Excellence (NICE) (2017) Spondyloarthritis in over 16s: diagnosis and management. (Nice Guidelines 65). Available at: https://www.nice.org.uk/guidance/ng65/ [Acessed 20/1/2020] [4] Clarissa Canella, Bruno Schau, Elisio Ribeiro, Bruna Sbaffi, and Edson Marchiori. MRI in Seronegative Spondyloarthritis: Imaging Features and Differential Diagnosis in the Spine and Sacroiliac...