using a quantitative method , scintigraphy of si joints was performed by means of 99m technetium pyrophosphate in 21 patients with definite ankylosing spondylitis , in 17 control patients , and in 26 patients 'at risk ' , i.e . patients with complaints of back pain of the inflammatory type where on clinical grounds there was a possibility of sacroiliitis developing but with normal x-ray findings of the si joints .
C0038013
ankylosing
C0022417
joints