1. Anecdotally, if you ask seven different general internists about the most accurate imaging test for suspected osteomyelitis, most will mention magnetic resonance imaging (MRI), but some will mention bone scans and even others will bring up white blood cell (WBCs) scans. Several meta-analyses have been conducted on the test characteristics of imaging modalities for suspected osteomyelitis of the foot. However, the meta-analyses each used different sets of studies, and their conclusions were contradictory. The goal of this paper is to compare the sensitivity and specificity of these different imaging modalities. Introduction Methods Results Through four meta-analyses, ten original studies with a total of n=1,026 imaging studies (50% MRI; 29% bone scan; 21% WBC) were identified (see figure 1). The quality of the original studies varied widely. The sensitivity of MRI usage was 0.92 (95% CI: 0.88-0.95) and its specificity was 0.83 (95% CI: 0.77-0.88). Bone scan had a numerically lower sensitivity of 0.86 (95% CI: 0.80; 0.91) as well as a lower specificity of 0.60 (0.51; 0.68). The sensitivity of WBC scans was 0.83 (95% CI: 0.75, 0.90) while its specificity point estimate of 0.77 (95% CI: 0.69, 0.85) was somewhere between MRI and bone scan. See figure 2 for the ROC. Conclusions In the absence of a clearly superior test, MRI had the numerically best test characteristics for the diagnosis of osteomyelitis of the foot. Due to its high sensitivity, it should be used to rule in patients for a biopsy. If an MRI cannot be performed, a bone scan is the next best alternative to select biopsy candidates. Further study might elucidate heterogeneity. Contact Figure 2: Receiver Operator Curve for MRI (black), bone scan (red), and WBC scan (green). Original studies’ sample size determines the size of the rectangles (MRI), diamonds (bone scan), and ellipses (WBC scan) We searched PubMed for meta-analyses on the performance of magnetic resonance imaging (MRI), bone scan with technetium-99m, and white blood cell (WBC) scan in assessing patients for suspected osteomyelitis. The study results were pooled and point estimates and 95% confidence intervals (95% CI) for sensitivity and specificity were computed. The findings were summarized in a forest plot and a receiver operator curve (ROC). RevMan 5.1.6 (Nordic Cochrane Center, Copenhagen, Denmark) was used. NYU School of Medicine, New York, NY (BPG), National Institutes of Health, Bethesda, MD (ES, HG), and Johns Hopkins University/Sinai Hospital, Baltimore, MD (JMC) Benjamin P. Geisler, Elad Sharon, Helen Gharwan, John M. Cmar Test Characteristics of Imaging Modalities for Suspected Osteomyelitis of the Foot Benjamin P. Geisler, M.D., M.P.H. Resident, Categorical Residency Program in Internal Medicine New York University School of Medicine, New York, NY Email: bgeisler@post.harvard.edu Phone: (617) 863 0236 Twitter: @ben_geisler Website www.hcval.com Figure 1: Tables with true-positive (TP), false-positives (FP), false- negatives (FN), true-negatives (TN) and computed sensitivity/specificity.