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