Diagnostic Imaging In Vascular Graft Infection; A Meta-analysis. The Added Value of Nuclear Imaging Techniques and an Outdated Golden Standard

Abstract

Introduction - Vascular graft infection (VGI), a serious complication in vascular surgery, has a high morbidity and mortality rate. Diagnosis is being complicated by nonspecific symptoms and challenged by variable accuracy of different imaging techniques. This systematic review and meta-analysis was conducted to evaluate the role of various diagnostic imaging modalities in patients suspected of VGI. Methods - A systematic review was conducted according to the PRISMA guidelines. Randomized controlled trials and observational cohort studies were included. Data sources included PubMed/Medline, Embase and Cochrane from January 1997 until October 2017. 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)). Results -Out of 4259 papers, 14 articles were included, which contained 8 prospective and 6 retrospective articles. CTA, FDG-PET and FDG-PET/CT showed negligible to moderate heterogeneity, while WBC scintigraphy ± SPECT/CT showed considerable heterogeneity. Pooled sensitivity for CTA was 0.67, in contrast to FDG-PET of 0.94, FDG-PET/CT of 0.95, WBC scintigraphy of 0.90 and WBC scintigraphy with SPECT/CT of 0.99. The pooled specificities were for CTA 0.63, FDG-PET 0.70, FDG-PET/CT 0.80, WBC scintigraphy 0.88 and WBC scintigraphy SPECT/CT 0.82. Pre- and posttest results showed that best probability per imaging modality is achieved by a combination of nuclear imaging and CT, where WBC SPECT/CT favors FDG-PET/CT with a positive posttest probability of 96% versus 83%. Conclusion - This meta-analysis suggests the diagnostic accuracy of WBC scintigraphy combined with SPECT/CT revealed the highest accuracy in diagnosing VGI. However it is a time consuming technique and not always available. Therefore FDG-PET/CT may be favorable as initial imaging technique. The use of solitary CTA in diagnosing VGI seems to be obsolete.