Magnetic resonance imaging for diagnosing foot osteomyelitis - A meta-analysis

Background: Uncertainty exists regarding the optimal workup of patients with suspected osteomyelitis of the foot, many of whom have diabetes mellitus. We conducted a meta-analysis to determine the diagnostic test performance of magnetic resonance imaging (MRI) for osteomyelitis of the foot and compared this performance with that of technetium Tc 99m bone scanning, plain radiography, and white blood cell studies. Methods: We searched MEDLINE (from 1966 to week 3 of June 2006) and EMBASE (from 1980 to week 3 of June 2006) for English-language studies in which adults suspected of having osteomyelitis of the foot or ankle were evaluated by MRI. We then extracted data using a standard form derived from the Cochrane Methods Group. To summarize the performance of diagnostic tests, we used the summary receiver operating characteristic curve analysis, which relies on the calculation of the diagnostic odds ratio (DOR). We also examined subsets of studies defined by the presence or absence of particular design flaws or populations. Results: Sixteen studies met inclusion criteria. In all studies combined, the DOR for MRI was 42.1 (95% confidence interval, 14.8-119.9), and the specificity at a 90% sensitivity cut point was 82.5%. The DOR did not vary greatly among subsets of studies. In studies in which a direct comparison could be made with other technologies, the DOR for MRI was consistently better than that for bone scanning (7 studies-149.9 vs 3.6), plain radiography (9 studies-81.5 vs 3.3), and white blood cell studies (3 studies-120.3 vs 3.4). Conclusions: We found that MRI performs well in the diagnosis of osteomyelitis of the foot and ankle and can be used to rule in or rule out the diagnosis. Magnetic resonance imaging performance was markedly superior to that of technetium Tc 99m bone scanning, plain radiography, and white blood cell studies.