The scintigraphic investigation of sacroiliac disease.

Bone scintigraphs obtained with both Technetium-99m polyphosphate and Technetium-99m pyrophosphate have been abnormal at the sacroiliac joints of 44 patients with definite ankylosing spondylitis (AS). Because of the normal registration of the sacroiliac joints on bone scintigraphy, it has been necessary to develop a profile-scan technique to quantify the abnormality that proves to be significantly different from the normal finding. In 17 patients with a strong clinical suspicion of AS but normal radiographs, the sacroiliac joints have frequently been abnormal. This finding is meaningful because there is a common occurence in this group of the histocompatibility antigen HL A-B27, known to be a marker of AS. We also note the frequency of abnormal sacroiliac scinitigrams in 26 patients with rheumatoid arthritis and in a group of other diseases-Crohn's disease, uveitis, psoriasis, ulcerative colitis, and Reiter's disease-all of which share some of the manifestations of AS.