"In active disease, these lesions are depicted as reduced signal intensity of the rim of the endplate on T1 images and as increased signal intensity on STIR images, representing bone marrow oedema or osteitis. At this stage, plain films appear normal or may show Romanus erosions. Later in the disease course, the epiphyseal ring can appear hyperintense on T1WI. Such hyperintense lesions represent circumscribed areas of post-inflammatory fatty bone marrow degeneration. Only at this stage are shiny corners depicted by conventional radiography - that is, long after inflammation has run its course."
"There is an ongoing international debate about specificity. Although axial spondyloarthritis is characterised by typical MR imaging features 5, these findings may not be totally specific and may be seen in degenerative or other spinal disorders as well 2, as all forms of spondyloarthritis may ultimately develop into ankylosing spondylitis in patients with longstanding disease 2."