Tomography for evaluation of sacroiliitis.

The radiographs and charts of 18 patients were reviewed to determine if sacroiliac joint tomography clarified the equivocal or clinically inconsistent findings of other imaging procedures. In six of eight patients with proven sacroiliitis, tomography detected joint erosions or sclerosis that were not detected on routine pelvis radiographs. In the other 10 patients, tomography excluded sacroiliitis which had been initially suggested by plain radiographs (four patients), quantitative sacroiliac scintigraphy (three patients), or clinical findings (three patients). The estimated average skin radiation exposure was 1.27 R (0.33 mC/kg) per tomographic section. The authors conclude that tomography improves delineation of sacroiliac joint abnormalities, but its use should be restricted to problem cases because of the high radiation exposure.