Value of 18F-FDG PET/CT in diagnosis of prosthetic vascular graft infection after endovascular aortic repair

Objective To study the features and clinical value of 18F-fluorodeoxyglucose (FDG) PET/CT in prosthetic vascular graft infections (PVGIs) after endovascular aortic repair (EVAR). Methods Data of 27 patients (22 males and 5 females, age range: 21-77 years, average age: 42 years) who underwent PET/CT imaging after EVAR from October 2011 to January 2017 were studied retrospectively. A total of 11 cases were finally diagnosed as PVGIs (PVGIs group), and the remaining 16 cases were defined as the negative group. PET/CT imaging features were compared between two groups. The detection rates of PET/CT and aortic CT angiography (CTA) for PVGIs were calculated and compared. Two-sample t test and Fisher exact test were used for data analysis. Results Significant uptake of FDG around the stents was detected by PET/CT in all patients in PVGIs group. The maximum standardized uptake value (SUVmax ) of 11 patients in early imaging was 14.9±3.3 (10.8-21.8) and that of 9 patients in delayed imaging was 13.8±3.4 (10.6-19.1). Six patients of the negative group underwent the delayed imaging. No uptake or mild uptake of FDG around the stents was observed in negative group, with the SUVmax of 1.7±0.8(1.0-2.9) in early imaging and 1.6±0.7(1.1-2.5) in delayed imaging. SUVmax in negative group was significantly lower than that in PVGIs group (t values: 12.6 and 11.8, both P<0.001). Five patients in PVGIs group were diagnosed as graft infections by the aortic CTA, while the remaining 6 cases showed no definitive infection signs on aortic CTA. The detection rate of aortic CTA was 5/11, which was significantly lower than that of PET/CT (P<0.05). In negative group, 6 patients had abnormal FDG uptakes in other areas and were finally confirmed as infectious lesions (n=3) or malignant tumors (n=3). Conclusion Compared with aortic CTA, 18F-FDG PET/CT is more sensitive and accurate in detection and diagnosis of PVGIs after EVAR. Key words: Aortic disease; Surgical procedures, operative; Blood vessel prosthesis; Infection; Positron-emission tomography; Tomography, X-ray computed; Deoxyglucose