title: Computerized tomography of the sacro-iliac joints in the diagnosis of sacro-iliitis.
abstract: The radiological confirmation of sacro-iliitis is essential for the early diagnosis of ankylosing spondylitis. Conventional radiography is too insensitive to detect early changes in these joints, and radionuclide scintigraphy is a non-specific, though highly sensitive, technique. This study describes a preliminary survey of the use of computed tomography (CT) of the sacro-iliac joints in the diagnosis of early sacro-iliitis. Patients were selected for study from a routine rheumatology clinic. Entry criteria included a clinical suspicion of sacro-iliitis and normal or equivocal findings on conventional radiography. Twenty-two patients were selected for study. Nine had normal plain films and normal CT; four had equivocal plain films with conclusive evidence of sacro-iliitis on CT; in two cases, conventional radiographs were normal but CT showed clear evidence of sacro-iliitis; two other patients had equivocal findings on straight X-ray examination but normal CT. Computerized tomography of the sacro-iliac joints can be useful in the early diagnosis of sacro-iliitis if conventional radiography is equivocal or normal. Further controlled studies are necessary to establish the sensitivity and specificity of the technique.
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001168:Arthritis / Q000175:diagnosis*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011859:Radiography / Q000379:methods; D012446:Sacroiliac Joint; D014057:Tomography, X-Ray Computed / Q000379:methods*