The detection of endocarditis, post implantation grafts, arteritis and other related disorders by 18 F-FDG PET/CT.

Introduction: Positron emission tomography with computed tomography ( ¹⁸ F-FDG PET/CT) is a nuclear medicine diagnostic method which, unlike other technological modalities that asses anatomical features, detects increased glucose metabolism inside the cells, thus is very helpful in diagnosing cardiovascular infection and inflammation and also in therapy planning.
Aim: Aim of this study was to assess the significance of ¹⁸ F-FDG PET/CT in detection of an active disease in patients with infection and inflammation of cardiovascular system.
Material and Methods: In this cohort retrospective study 73 cardiovascular patients (56.9±15.3 years; 33 male and 40 female) with persistent symptoms of inflammatory syndrome were referred to ¹⁸ F-FDG PET/CT in order to evaluate active disease. Biochemical blood analyses (erytrocite sedimentation, CRP, leukocytic formula), CT, MRI, ultrasound were performed in all the patients. Out of 73 patients, 7 had a second ¹⁸ F-FDG PET/CT examination (62.1±12.3 years; 6 men and 1 woman) with a previous pathological PET/CT finding after which the therapy was changed. The degree of metabolic activity was analyzed visually and quantitatively using the maximal standardized uptake value (SUV _max ). ¹⁸ F-FDG PET/CT findings were considered positive in case of higher focal glucose accumulation in projection of heart and diffuse uptake in blood vessels' wall than accumulation in surrounding tissue and liver.
Results: Vasculitis was diagnosed in 36 patients (49,3%), endocarditis in 23 (31,5%) and graft inflammation in 14 (19,2%). The results were compared to the gold standard, biopsy of the blood vessel and histopathological verification during surgical treatment, or clinical follow up. Forty nine patients with the sights of an increased FDG uptake were considered true positive (TP) (SUV _max 5.7±2.9). In 21 patients ¹⁸ F-FDG uptake was physiological and they were considered true negative (ТN). Two who used corticosteroid therapy which decreases inflammation, were false negative (FN), and only 1 false positive (FP) finding in the region of recent iatrogenic vein injury. Sensitivity of this method was 96.08±, specificity 95.45±, positive predictive value 98.0±, negative predictive value 91.3± and accuracy 95.89±.
Conclusion: Our results indicate that ¹⁸ F-FDG PET/CT could be useful diagnostic method for the detection of sights of metabolically active disease in patients with persistent symptoms of infection and inflammation of cardiovascular system, as well as in monitoring therapy response.