%0 Journal Article
%T Diagnosis and Progression of Sacroiliitis in Repeated Sacroiliac Joint Computed Tomography
%A Mats Geijer
%A Gro Gadeholt G£¿thlin
%A Jan H. G£¿thlin
%J Arthritis
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/659487
%X Objective. To assess the clinical utility of repeat sacroiliac joint computed tomography (CT) in sacroiliitis by assessing the proportion of patients changing from normal to pathologic at CT and to which degree there is progression of established sacroiliitis at repeat CT. Methods. In a retrospective analysis of 334 patients (median age 34 years) with symptoms suggestive of inflammatory back pain, CT had been performed twice, in 47 of these thrice, and in eight patients four times. The studies were scored as normal, equivocal, unilateral sacroiliitis, or bilateral sacroiliitis. Results. There was no change in 331 of 389 repeat examinations. Ten patients (3.0%) had progressed from normal or equivocal to unilateral or bilateral sacroiliitis. Of 43 cases with sacroiliitis on the first study, 36 (83.7%) progressed markedly. Two normal cases had changed to equivocal. Eight equivocal cases were classified as normal on the repeat study. In further two patients, only small changes within the scoring grade equivocal were detected. Conclusions. CT is a valuable examination for diagnosis of sacroiliitis, but a repeated examination detects only a few additional cases of sacroiliitis. Most cases with already established sacroiliitis showed progression of disease. 1. Introduction Radiology plays an important role in diagnostic criteria for ankylosing spondylitis (AS) such as the New York (NY) criteria [1] and the modified NY criteria [2]. In classification criteria of spondyloarthropathies, it has been of minor importance [3, 4]. However, the recent Assessment of SpondyloArthritis International Society (ASAS) criteria from 2009 require sacroiliitis on imaging plus one or more spondyloarthritis features or positive serology for HLA-B27 plus two or more spondyloarthritis features for spondyloarthropathy classification [5]. Computed tomography (CT) has notably higher accuracy than radiography in imaging of the sacroiliac joints [6], especially for evaluation of chronic changes from sacroiliitis. Even though both sensitivity and specificity of CT are high, some examinations cannot with certainty be classified as either normal (i.e., showing no or only incidental degenerative or other findings) or as showing unequivocal sacroiliitis, as is the case with all imaging modalities. A review of the literature reveals the usually long delay between onset of clinical symptoms and definite radiographic signs of sacroiliitis [7¨C9]. It has, however, been reported that patients with spondyloarthropathy may show significantly increased inflammatory joint changes already at one-year
%U http://www.hindawi.com/journals/arthritis/2013/659487/