Diagnostic Imaging in Vascular Graft Infection: A Systematic Review and Meta-Analysis

Background Vascular graft infection (VGI), a serious complication in vascular surgery, has a high morbidity and mortality rate. The diagnosis is complicated by non-specific symptoms and challenged by the variable accuracy of different imaging techniques. The objective of this study was to determine the diagnostic value of various imaging techniques to diagnose VGI. Methods A systematic review was conducted according to the PRISMA guidelines. Data sources included PubMed/Medline, Embase, and Cochrane from January 1997 until October 2017. Observational cohort studies were included. A meta-analysis was conducted on several imaging modalities: computed tomography with or without angiography (CT(A)), 18 F-fluoro- d -deoxyglucose positron emission tomography with or without low dose or contrast enhanced CT (FDG-PET(/CT)), and white blood cell scintigraphy with or without single photon emission computed tomography combined with low dose CT (WBC (SPECT/CT)). Results Of 4259 papers, 14 articles were included, containing eight prospective and six retrospective articles. CTA ( I 2 7.4%), FDG-PET ( I 2 36.5%), and FDG-PET/CT ( I 2 36.6%) showed negligible to moderate heterogeneity, while WBC scintigraphy ± SPECT/CT ( I 2 78.6%) showed considerable heterogeneity. Pooled sensitivity for CTA was 0.67 (95% CI 0.57–0.75), in contrast to FDG-PET of 0.94 (95% CI 0.88–0.98), FDG-PET/CT of 0.95 (95% CI 0.87–0.99), WBC scintigraphy of 0.90 (95% CI 0.85–0.94), and WBC scintigraphy with SPECT/CT of 0.99 (95% CI 0.92–1.00). The pooled specificities were for CTA 0.63 (95% CI 0.48–0.76), FDG-PET 0.70 (95% CI 0.59–0.79), FDG-PET/CT 0.80 (95% CI 0.69–0.89), WBC scintigraphy 0.88 (95% CI 0.81–1.94), and WBC scintigraphy SPECT/CT 0.82 (95% CI 0.57–0.96). Pre- and post-test results showed that WBC SPECT/CT favours FDG-PET/CT, with a positive post-test probability of 96% versus 83%. Conclusion This meta-analysis suggests the diagnostic performance of WBC scintigraphy combined with SPECT/CT is the greatest in diagnosing VGI. However, it is a time consuming technique and not always available. Therefore FDG-PET/CT may be favourable as the initial imaging technique. The use of solitary CTA in diagnosing VGI seems to be obsolete.