Figure 7  .

MRI and SJ biopsy specimen of a 36 year old female HLA B27+ AS patient with a disease duration of 10 years with bilateral inflammatory low back pain. (A) T2* weighted gradient echo sequence showing definite chronic changes with bilateral marked subcondral sclerosis (s), huge erosions (white arrows) and some bony bridges crossing the joint spaces (curved white arrows) (bilateral chronicity grade III-IV, bilateral activity grade a, not shown). (B) The biopsy specimen shows a sparse cellular infiltrate (black arrow) with an avital piece of cartilage (black open arrow) surrounded by a large area of bone (haematoxylin and eosin staining, original magnification × 250).