Physiological Appearance of Hybrid FDG–Positron Emission Tomography/Computed Tomography Imaging Following Uncomplicated Endovascular Aneurysm Sealing Using the Nellix Endoprosthesis

Abstract

Purpose: To investigate the physiological uptake of hybrid fluorine-18-fluorodeoxyglucose (FDG)–positron emission tomography/computed tomography (PET/CT) before and after an uncomplicated endovascular aneurysm sealing (EVAS) procedure as a possible tool to diagnose EVAS graft infection and differentiate from postimplantation syndrome. Materials and Methods: Eight consecutive male patients (median age 78 years) scheduled for elective EVAS were included in the prospective study ( ClinicalTrials.gov identifier NCT02349100). FDG-PET/CT scans were performed in all patients before the procedure and 6 weeks after EVAS. The abdominal aorta was analyzed in 4 regions: suprarenal, infrarenal neck, aneurysm sac, and iliac. The following parameters were obtained for each region: standard uptake value (SUV), tissue to background ratio (TBR), and visual examination of FDG uptake to ascertain its distribution. Demographic data were obtained from medical files and scored based on reporting standards. Results: Visual examination showed no difference between pre- and postprocedure FDG uptake, which was homogenous. In the suprarenal region no significant pre- and postprocedure differences were observed for the SUV and TBR parameters. The infrarenal neck region showed a significant decrease in the SUV and no significant decrease in the TBR. The aneurysm sac and iliac regions both showed a significant decrease in SUV and TBR between the pre- and postprocedure scans. Conclusion: Physiological FDG uptake after EVAS was stable or decreased with regard to the preprocedure measurements. Future research is needed to assess the applicability and cutoff values of FDG-PET/CT scanning to detect endograft infection after EVAS.

Difficult diagnosis and management of a complicated Nellix graft infection

“…This is because they are difficult to interpret due to false positives from low-grade inflammation associated with prosthetic grafts (17) . Recent work by Jebbink et al (4) , however, suggests this may be different for the Nellix graft. They found decreased FDG uptake at six weeks post-deployment in non-infected Nellix stent-grafts and suggests early inflammation may be less of an issue compared to EVAR.…”

“…This aims to mitigate Type-2 endoleak that are associated with late failures with EVAR (2) . Endograft infections are rare but life-threatening complications with an incidence of 0.2-0.7% and mortality rates up to 50% (3,4) . Incidence rates of 0.6-1.2% have been reported for Nellix stent-grafts (5)(6)(7) .…”

“…Diagnosing stent-graft infection is challenging. Computed Tomography (CT) and 18Ffluorodeoxyglucose positron emission tomography (FDG-PET) are frequently utilised in combination (4) . We describe the management of a complicated Nellix stent-graft infection where FDG-PET/CT was difficult to interpret.…”

Utility of multimodal molecular imaging in the diagnosis and decision-making in arterial diseases

“…Aortic graft infection (AGI) can occur when microorganism colonization develops in a primary prosthesis following open surgical reconstruction or an endovascular aortic repair (EVAR) [ 24 ]. Although it is a late, rare complication with an incidence ranging from 0.16% to 0.77%, this is a life-threatening condition with a mortality rate of 18-50% [ 25 ].…”

Imaging of Vascular Graft/Endograft Infection with Radiolabeled White Blood Cell Scan and [18F]FDG PET/CT

“…In a prospective study by Groot Jebbink et al comparing [ 18 F]FDG PET/CT before and 6 weeks after uncomplicated endovascular aneurysm sealing (EVAS), the homogenous uptake pattern, SUVmax, and TBR were stable before and after the procedure [32]. Marie et al reported no increased [ 18 F]FDG uptake 1 month after EVAR compared with the [ 18 F]FDG uptake before the procedure [33].…”