Spinal Changes in Patients with Spondyloarthritis: Comparison of MR Imaging and Radiographic Appearances

Abstract

Since the advent of highly effective TNF-alpha inhibitors for treating spondyloarthritides, referring rheumatologists have been requesting the sensitive visualization of inflammatory changes not only of the sacroiliac joints but of the entire spine. Given that changes in spondyloarthritis may be very subtle, their visualization by means of magnetic resonance (MR) imaging relies critically on selecting the proper imaging protocol. Spinal changes associated with spondyloarthritis are florid anterior spondylitis (or Romanus lesion), florid diskitis (or Andersson lesion), ankylosis, insufficiency fractures of the ankylosed spine, syndesmophytes, arthritis of the apophyseal and costovertebral joints, and enthesitis of the interspinal ligaments. A comparison of MR imaging findings with those of conventional radiography in individual patients reveals strengths and weaknesses of both modalities. Results of this comparison suggest that syndesmophytes are depicted better with radiography; ankylosis, equally well with both imaging techniques; and all other lesions, better with MR imaging. Classification of the different findings based on the typical signal-intensity changes seen on MR images enables standardized reporting, and scoring the lesions may be helpful in clinical trials.

Complications of the spine in ankylosing spondylitis with a focus on deformity correction

“…1). 29,40,47 In an early study cohort, Romanus lesions were present in 53% of patients; Andersson lesions were more rare and occurred iñ 4%. 54 On MR imaging, short tau inversion recovery sequences show hyperintensity of the involved areas for both lesions, before the radiographically demonstrated changes appear.…”

“…47 On radiographs, Andersson lesions appear as a spondylodiscitis that destroys the central portion of the intervertebral disc and adjacent vertebral body. 29 Romanus lesions are erosive changes at the anterior and posterior vertebral endplates that appear as "shiny corners" on radiographs (Fig. 1).…”

“…54 On MR imaging, short tau inversion recovery sequences show hyperintensity of the involved areas for both lesions, before the radiographically demonstrated changes appear. 29 In late disease, Romanus lesions cause a characteristic squaring of vertebral bodies. 47 Andersson lesions are often mistaken for an infectious process, but cultures and histological studies reveal no causative organism.…”

“…47 Andersson lesions are often mistaken for an infectious process, but cultures and histological studies reveal no causative organism. 15,29 Enthesitis, Synovitis, Syndesmophytes, and Enthesophytes Enthesitis, inflammation of the insertion points of ligaments and tendons that are ubiquitous in the spine, is considered the characteristic inflammatory lesion in AS. Andersson and Romanus lesions result from enthesitis.…”

“…Magnetic resonance imaging reveals enhancement in these tissues when inflammation is present. 29 It is hypothesized that the inflammatory lesions of AS lead to new bone formation as opposed to the erosive changes that occur in rheumatoid arthritis. Ossification occurs in both entheses and synovial articulations.…”