The Diagnostic Value of Scintigraphy in Assessing Sacroiliitis in Ankylosing Spondylitis: a Systematic Literature Research

Background: The diagnostic value of scintigraphy in detecting sacroiliitis in patients with spondyloarthritis is not clear.

Objective: To assess the diagnostic value of scintigraphy in detecting sacroiliitis in ankylosing spondylitis (AS) and in patients with clinically probable sacroiliitis without x-ray changes.

Materials And Methods: A systematic literature research was performed in the Pubmed and Medline database up to August 2007. Articles in English and German on patients with established AS and clinically probable sacroiliitis without x-ray changes were selected. In addition, studies including patients with mechanical low back pain as a control group were searched. Pooled sensitivity, specificity and positive and negative likelihood ratios were calculated.

Results: In total 99 articles about scintigraphy were found. 25 articles were included into the analysis. Overall sensitivity for scintigraphy to detect sacroiliitis was 51.8% for patients with established AS (n = 361) and 49.4% for patients with probable sacroiliitis (n = 255). Sensitivity of scintigraphy in patients with AS with inflammatory back pain (indicating ongoing inflammation) was 52.7% (n = 112) and in patients with AS and suspected sacroiliitis with magnetic resonance imaging showing acute sacroiliitis (as a gold standard) was 53.2% (n = 62). In controls with mechanical low back pain specificity was 78.3% (n = 60) resulting in likelihood ratios not higher than 2.5-3.0.

Conclusion: These data as a result of a literature research suggest that scintigraphy of the sacroiliac joints is at most of limited diagnostic value for the diagnosis of established AS, including the early diagnosis of probable/suspected sacroiliitis.