Diagnostic imaging of sacroiliac joints and the spine in the course of spondyloarthropathies

Abstract

Spondyloarthropathies belong to a group of rheumatic diseases, in which inflammatory changes affect mainly the sacroiliac joints, spine, peripheral joints, tendon, ligaments and capsule attachments (entheses). This group includes 6 entities: ankylosing spondylitis, arthritis associated with inflammatory bowel disease, reactive arthritis, undifferentiated spondyloarthropathy, psoriatic arthritis and juvenile spondyloarthropathy. In 2009, ASAS (Assessment in SpondyloArthritis international Society) association, published classification criteria for spondyloarthropathies, which propose standardization of clinical-diagnostic approach in the case of sacroiliitis, spondylitis and arthritis. Radiological diagnosis of inflammatory changes of sacroiliac joints is based on a 4 step radiographic grading method from 1966. According to modified New York criteria, the diagnosis of ankylosing spondylitis is made based on the presence of advanced lesions, sacroiliitis of at least 2 grade bilaterally or 3-4 unilaterally. In case of other types of spondyloarthropathies diagnosis is made based on presence of at least grade 1 changes. In MRI, active inflammation of sacroiliac joints is indicated by the presence of subchondral bone marrow edema, synovitis, bursitis, or enthesitis. ASAS discusses only the classic form of axial spondyloarthropathies, which is ankylosing spondylitis. To quantify radiological inflammatory changes in the course of the disease, Stoke Ankylosing spondylitis classification Spinal Score (SASSS) is recommended. The signs of inflammation and scarrying of the spinal cord in the course of ankylosing spondylitis, present in MRI include: bone marrow edema, sclerosis, fat metaplasia, formation of syndesmophytes, and ankylosis.

Keywords: diagnostics; magnetic resonance imaging; radiograms; sacroiliitis; spondyloartropathies.

Figures

Figure 1

Sacroilitis: (A) grade 1; (B) grade 2; (C) grade 3; (D) grade 4.

Figure 2

X-ray examination of lumbar spine in AP (A) and lateral projection (B): „bamboo spine” (rigidity of several segments), squaring of L5 vertebral body, syndesmophytes, ankylosis of intervertebral joints.

Figure 3

Lateral x-ray of cervical spine: anterior dislocation, syndesmophytes on levels C3/C4 and C5/C6, ankylosis of C2–C6 intervertebral joints.

Figure 4

MR examination of sacroiliac joints, images: T1- (A), T2 TIRM (B), T1FSCE-weighted (C): bone marrow edema, more pronounced in right sacroiliac joint, particularly in the iliac bone as well as erosions undergoing strong enhancement following administration of contrast medium, contrast enhancement and thickening of synovial membrane in the sacroiliac joint (synovitis), inflammation of right sacroiliac joint capsule (capsulitis), subchondral sclerosis – more pronounced on the left.

Figure 5

Chronic inflammation in sacroiliac joints in T1- (A) and T1FS-weighted (B) images: fatty transformation of the sacral bone and iliac bones, partial sacroiliac joint ankylosis on right side.

Figure 6

„Shiny corners” of anterior vertebral bodies in the lumbar region; inflammation of intervertebral joints L1–L5 with signs of bone marrow edema in T2 TIRM image (A) enhanced after administration of contrast medium in T2FSCE-weighted image (B).