Sacroiliac joint uptake ratios in inflammatory bowel disease: relationship to back pain and to activity of bowel disease.

Sacroiliac uptake ratios based on 99Tcm methylene diphosphonate images were calculated in 14 patients with ankylosing spondylitis, 23 patients with non-specific backache, 33 patients with inflammatory bowel disease (ulcerative colitis 19, Crohn's disease 14) and 33 control subjects. Twenty-eight of the control subjects were patients referred from a breast cancer clinic. In the control subjects, and in 20 patients with inflammatory bowel disease who did not have back pain, sacroiliac ratios decreased significantly with increasing age (p less than 0.001 and p less than 0.01 respectively). Sacroiliac uptake ratios were significantly higher in ankylosing spondylitis than in patients with non-specific backache. Seven of the 14 patients with ankylosing spondylitis had higher sacroiliac ratios than any recorded in the control subjects. Eleven patients with inflammatory bowel disease had abnormally high sacroiliac uptake ratios; ten of these patients had back pain. Increased sacroiliac joint uptake in such patients may reflect early sacroiliitis. No relationship was detected between sacroiliac uptake and the activity of the bowel disease. Sacroiliac uptake ratios were significantly higher in the inflammatory bowel disease patients suffering from back pain than in age and sex matched patients with (a) inflammatory bowel disease but no back pain or (b) non-specific backache.