Added Value of Abnormal Lymph Nodes Detected with FDG-PET/CT in Suspected Vascular Graft Infection.

Vascular graft and endograft infections (VGEI) cause a serious morbidity and mortality burden. 18 F-fluorodeoxyglucose positron emission tomography/computed tomography ( 18 F-FDG PET/CT) imaging is frequently used in the diagnostic workup, but the additional value of abnormal ( 18 F-FDG active and/or enlarged) locoregional lymph nodes is unknown. In this retrospective study, the additional diagnostic value of abnormal locoregional lymph nodes on 18 F-FDG PET/CT imaging for VGEI was evaluated, including 54 patients with a culture-proven VGEI (defined according to the Management of Aortic Graft Infection [MAGIC] group classification) and 25 patients without VGEI. 18 F-FDG PET/CT was qualitatively and quantitatively assessed for tracer uptake and pattern at the location of the vascular graft, and locoregional lymph node uptake and enlargement (>10 mm). 18 F-FDG uptake intensity and pattern independently predicted the presence of VGEI by logistic regression (Χ 2 : 46.19, p < 0.001), with an OR of 7.38 (95% CI [1.65, 32.92], p = 0.009) and 18.32 (95% CI [3.95, 84.88], p < 0.001), respectively. Single visual assessment of abnormal locoregional lymph nodes predicted the presence of VGEI with a sensitivity of 35%, specificity of 96%, PPV of 95%, and NPV of 41%. The visual assessment of abnormal lymph nodes after qualitative assessment of 18 F-FDG uptake intensity and pattern at the vascular graft location did not independently predict the presence of VGEI by logistic regression (Χ 2 : 3.60, p = 0.058; OR: 8.25, 95% CI [0.74, 63.37], p = 0.096). In conclusion, detection of abnormal locoregional lymph nodes on 18 F-FDG PET/CT has a high specificity (96%) and PPV (95%) for VGEI. However, it did not add to currently used 18 F-FDG PET/CT interpretation criteria.