Prospective evaluation of sacroiliac scintigraphy in chronic inflammatory back pain.

To assess the usefulness in screening for sacroiliitis of a wide band profile cut which included the entire sacroiliac (SI) joint, 34 patients with chronic inflammatory back pain (IBP) underwent sacroiliac joint scintigraphy with 99mTc-methylene diphosphonate while receiving no antiinflammatory therapy. The sacroiliac joint to sacrum (SIJ/S) ratios in those with back pain differed significantly from the ratios of an age-matched control group. However, 12 of the 34 patients with inflammatory back pain had normal or equivocal sacroiliac radiographs and 4 of 12 had normal SIJ/S ratios. All 4 were HLA-B27 positive, had diminished lumbar movement, and required antiinflammatory medication; 2 had diminished chest expansion; 1 has developed iritis. We conclude that this technique is not a reliable screening procedure. Therapy with antiinflammatory drugs was associated with a significant decrease in the SIJ/S ratios in 19 of the 34 who were reimaged.