Radiographic sign seen in Ankylosing Spondylitis

1.

Inman, Robert D., Rahman, Proton (2024). In Goldman-Cecil Medicine (pp. 1760). DOI: 10.1016/B978-0-323-93038-3.00244-6

Radiographic assessment is important to confirm the diagnosis, but no radiographic changes may be seen in the sacroiliac joints early in the course of disease. If the clinician has a high index of suspicion, MRI may improve the sensitivity of the plain radiograph because inflammatory changes on MRI predate radiographic changes. A routine anteroposterior pelvic radiograph is generally the standard diagnostic radiograph, and the classic findings are bilateral changes in the sacroiliac joints (Fig. 244-2). Abnormalities include erosions in the joint line, pseudowidening, subchondral sclerosis, and, finally, ankylosis that reflects complete bony replacement of the sacroiliac joints. Radiographs of the spine may reveal squaring of the vertebral bodies (loss of the normal anterior concavity of the lumbar vertebra) and “shiny corners” (subchondral sclerosis at the upper edge of the vertebral body), both of which are manifestations of enthesitis. Syndesmophytes, which represent marginal bridging of the vertebrae (Figs. 244-3and244-4), eventually develop and make the diagnosis clear. Because ankylosis of the apophyseal joints may occur without syndesmophyte formation, it is important to assess the posterior joints on lateral views of the lumbosacral spine, as well as the anterior margin of the vertebrae. Eventually, the changes may result in a “bamboo spine,” so called because the bridging syndesmophytes can mimic the appearance of bamboo.

2.

Weiss, Pamela F. (2025). In Nelson Textbook of Pediatrics (pp. 1483). DOI: 10.1016/B978-0-323-88305-4.00197-8

Conventional radiographs detect chronic bony changes and damage but not active inflammation and are unreliable in the assessment of pediatric disease. Early radiographic changes in the sacroiliac joints include indistinct margins and erosions.Sclerosistypically starts on the iliac side of the joint (Fig. 197.4). Peripheral joints may exhibit periarticularosteoporosis, with loss of sharp cortical margins in areas of enthesitis, which may eventually show erosions or bony spurs (enthesophytes). Squaring of the corners of the vertebral bodies and syndesmophyte formation resulting in the classic “bamboo spine” characteristic of advanced AS are rare in early disease, particularly in childhood. CT, like radiographs, can detect chronic bony changes but not active inflammation and has the disadvantage of more radiation exposure. The gold standard for early visualization of sacroiliitis is evidence of bone marrow edema adjacent to the joint on MRI with fluid-sensitive sequences such as short-T1 inversion recovery (STIR) (Figs. 197.5 and 197.6). Gadolinium does not add value to the study of the sacroiliac joints if STIR is used. MRI will reveal abnormalities before the plain radiograph. Wholebody MRI may also be used to evaluate the axial skeleton in adults with early disease because it can detect vertebral lesions in addition to sacroiliac changes.

3.

Elsevier ClinicalKey Clinical Overview

Diagnosis In patients presenting with pain, maintain a high index of suspicion for unstable fractures and immobilize properly before imaging Plain radiographs of pelvis (anteroposterior and Ferguson views) Indicated for all patients with suspected ankylosing spondylitis Sacroiliitis is earliest radiographic manifestation Syndesmophytes may be detected in lumbar and cervical spine Radiographic grading of sacroiliitis 0: normal width, sharp joint margins I: suspicious II: sclerosis, some erosions III: severe erosions, pseudodilation of the joint space, partial ankylosis IV: complete ankylosis Modified New York criteria define sacroiliitis as grade II or higher bilaterally, or grade III to IV unilaterally Pelvic MRI Indicated when ankylosing spondylitis is suspected but radiographic findings are normal; also an alternative to radiographs in young patients with short duration of symptoms Demonstrates acute inflammatory changes (bone marrow edema) Can also demonstrate chronic structural lesions (eg, bone erosion, new bone formation, sclerosis, fat infiltration)

Diagnosis Suspect diagnosis on basis of history and clinical findings suggestive of inflammatory back pain and presence of peripheral articular and extra-articular manifestations No specific laboratory tests are required to establish diagnosis; however, HLA-B27–positive status helps to support diagnosis Plain radiography of pelvis and sacroiliac joints is the initial imaging method Presence of sacroiliitis on pelvic radiographs supports diagnosis but is not obligatory MRI is indicated when diagnosis cannot be established on radiographic basis; this may be an alternative to radiographs in young patients with short duration of symptoms There are no true diagnostic criteria; however, classification criteria have been developed and are frequently used to aid diagnosis Modified New York criteria (1984) require radiographic evidence of sacroiliitis in addition to at least 2 of the 3 following clinical findings: Low back pain and stiffness of at least 3 months duration, improved by exercise and not relieved by rest (ie, inflammatory back pain) Quantified limitation of lumbar spine motion in lateral and frontal planes Quantified limitation of chest expansion relative to reference range values for age and sex Assessment of SpondyloArthritis International Society developed criteria for classification of axial spondyloarthritis (which encompasses ankylosing spondylitis and nonradiographic axial spondyloarthritis) more recently that includes a clinical arm and an imaging arm Imaging arm Requires evidence of sacroiliitis on either conventional radiography or MRI plus at least 1 of the features of axial spondyloarthritis Clinical arm Requires presence of HLA-B27 and at least 2 other of the features of axial spondyloarthritis Features of axial spondyloarthritis Inflammatory back pain Arthritis Enthesitis (heel) Uveitis Dactylitis Psoriasis Inflammatory bowel disease Good response to NSAIDs

4.

Du MS, Xiong XQ, Liu H, et al. BMC Musculoskeletal Disorders. 2021;22(1):919. doi:10.1186/s12891-021-04716-5. Copyright License: CC BY

Publish date: November 1, 2021.

BACKGROUND: Bone marrow edema of the sacroiliac joint is the early imaging manifestation, an indicator of inflammatory activity of ankylosing spondylitis (AS) (Yang R, et. al. Medicine (Baltimore) 98:e14620, 2019). OBJECTIVE: The aim of the study was to investigate the value of magnetic resonance imaging (MRI) Dixon sequence in the diagnosis of marrow edema of the sacroiliac joint in patients with AS. METHODS: Forty-five patients with AS admitted in our hospital between November 2016 and February 2019 were selected retrospectively as the case group. Forty-five healthy subjects recruited between November 2016 and February 2019 served as the control group. Bath ankylosing spondylitis disease activity index (BASDAI), Bath ankylosing spondylitis functional index (BASFI), C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR)... (truncated preview)