Akademik Veri Yönetim Sistemi
Annual Congress of the European Association of Nuclear Medicine, Barcelona, İspanya, 4 Ekim - 08 Kasım 2025, ss.247, (Tam Metin Bildiri)
Aim/Introduction: Differentiating adrenal lesions on F-18 FDG PET/CT remains a diagnostic challenge. In addition to visual assessment, the use of quantitative PET/CT parameters enhances diagnostic accuracy. This study aimed to evaluate the contribution of quantitative parameters in distinguishing benign from malignant adrenal lesions. Materials and Methods: In this retrospective study, we analyzed 569 patients who underwent FDG PET/CT between 2011 and 2024. A total of 165 patients with 192 lesions, confirmed by follow-up MRI or histopathology, were included. Parameters assessed included lesion size, laterality, SUVmax, metabolic tumor volume (MTV), total lesion glycolysis (TLG), and Hounsfield units (HU). For metabolic parameters, three-dimensional regions of interest (ROIs) were delineated. Group comparisons were performed using Kruskal-Wallis and Mann-Whitney U tests. ROC analysis was applied to determine optimal diagnostic thresholds. Results: The cohort included 165 patients (mean age: 59 ± 15 years; 75 males, 90 females), with 27 presenting bilateral lesions. Based on pathology and MRI results, six subgroups (G1-6) were defined. Mean values for PET/CT and CT-derived parameters were calculated for each group. Of the 165 patients, 84 had adenomas (G1), 10 had pheochromocytomas (G2), 37 had adrenocortical carcinomas or metastases (G3), 8 had hyperplasia (G4), 5 had myelolipomas (G5), and 21 had other lesions (G6). Mean PET/CT and CT parameters per group are shown in Table 1. According to ROC analysis, the SUVmax cut-off values were: ≤4.10 for Group 1 (sensitivity 84.2%, specificity 70.4%) and >5.47 for Group 3 (sensitivity 88.4%, specificity 87.9%) (p<0.001). The MTV cut-off values were: ≥33.37 for Group 3 (sensitivity 74.4%, specificity 82.6%). TLG cut-off values were: ≤93.10 for Group 1 (sensitivity 85.1%, specificity 70.2%) (p<0.001) and >93.10 for Group 3 (sensitivity 83.7%, specificity 83.2%)(p<0.001). The HU cut-off value for Group 5 was found to be ≤-17.95 (sensitivity 100%, specificity 95.7%)(Table 2). Lesion-based analysis showed statistically significant differences between Group 1 and Group 3 across all parameters (p<0.001). Although SUVmax did not significantly differ between Group 2 and Group 3 (p=0.063), volumetric parameters—MTV (p=0.009) and TLG (p=0.007)—were significantly higher in Group 3 (Table 3). Conclusion: Quantitative FDG PET/CT parameters, especially the volumetric metrics, offer valuable diagnostic insight into adrenal lesion characterization. The combination of MTV and TLG with SUVmax enhances lesion characterization, informs biopsy planning, and may help avoid unnecessary interventions. Furthermore, these parameters aid not only in distinguishing benign from malignant lesions but also in differentiating pheochromocytomas from malignant adrenal tumors.