The radiographic diagnosis of sacroiliitis. A comparison of different views with computed tomograms of the sacroiliac joint.

Conventional radiography is the standard method of objectively identifying sacroiliitis. Single views of the sacroiliac joints can be unequivocally interpreted in 70-80% of patients with low back pain. A series of views usually correctly resolves the ambiguity in the remaining 20-30% of patients (67% correct). Computed tomography will be helpful in the few patients in whom a series of views produces equivocal interpretation.