Background: Abnormal activity of ¹⁸F-FDG PET/CT is a major Duke criterion in the diagnostic work-up of infective prosthetic valve endocarditis (IE). We hypothesized that quantitative lesion assessment by ¹⁸F-FDG PET/CT-derived standard maximum uptake ratio (SURmax), metabolic active volume (MTV) and total lesion glycolysis (TLG) might be useful in distinct subgroups of IE patients (e.g. IE-related abscess formation).

Methods: All patients (n=27) hospitalized in our tertiary IE referral medical center from January 2014 to October 2018 with preoperatively performed ¹⁸F-FDG PET/CT and surgically confirmed IE were included into this retrospective analysis.

Results:  In patients with surgically confirmed abscess formation (n=10) we found that MTV (by ~5-fold) and TLG (by ~7-fold) were significantly increased as compared to patients without present abscess (n=17). Receiver operation characteristics (ROC) analyses demonstrated that TLG (calculated as MTV x SURmean, i.e. TLG (SUR)) had the most favorable area under the ROC curve (0.841 [CI: 0.659-1.000]) in predicting IE-related abscess formation. This resulted in a sensitivity of 80% and a specificity of 88% at a cut-off value of 14.14 ml for TLG (SUR).  

Conclusion: We suggest that ¹⁸F-FDG PET/CT-derived quantitative assessment of TLG (SUR) may provide a novel diagnostic tool in predicting endocarditis-associated abscess formation.