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

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. 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)), 18F-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)). Of 4259 papers, 14 articles were included, containing eight prospective and six retrospective articles. CTA (I2 7.4%), FDG-PET (I2 36.5%), and FDG-PET/CT (I2 36.6%) showed negligible to moderate heterogeneity, while WBC scintigraphy ± SPECT/CT (I2 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%. 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.