Sunday, July 5, 2009

Shiny corner sign in Ankylosing Spondylitis

38 year old male with recently diagnosed ankylosing spondylitis, lateral lumbar spine radiograph showing increased density (arrow) in the anteroinferior part of L3 vertebral body suggetive of shiny corner sign. MR STIR image shows increased signal in anteroinferior parts (arrows) of L3 and L5 bodies.

Shiny corner sign, also known as a Romanus lesion, is an early spinal finding in ankylosing spondylitis. These represent small erosions at the superior and inferior endplates (corners on lateral radiograph) of the vertebral bodies, with surrounding reactive sclerosis. Eventually the vertebral bodies become squared.

On MRI the 'shiny corners' appear as areas of increased T1 signal due to focal fatty marrow as a result of chronic inflammation. MRI however can detect changes earlier than x-ray manifestations, when there is initially increased T2 signal on STIR and decreased signal on T1WI. At this stage plain films appear normal.

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