ĐẶC ĐIỂM HÌNH ẢNH TÁI PHÁT/DI CĂN TRÊN 18F-FDG PET/CT Ở BỆNH NHÂN UNG THƯ TUYẾN GIÁP THỂ NHÚ

Abstract

Objective: This study aimed to evaluate the imaging characteristics of recurrent and metastatic lesions detected by 18F-FDG PET/CT in patients with papillary thyroid carcinoma (PTC) who had elevated serum thyroglobulin (Tg) levels and negative diagnostic 131I whole-body scans—a condition known as TENIS (Thyroglobulin Elevated, Negative Iodine Scintigraphy) syndrome. Methods: We conducted a prospective cross-sectional study involving 50 patients with PTC who underwent total thyroidectomy and radioactive iodine therapy. All patients had stimulated serum Tg levels >10 ng/mL and negative 131I scans, and were referred for 18F-FDG PET/CT imaging at Hanoi Oncology Hospital between January 2023 and January 2025. PET/CT findings were assessed in terms of lesion location, maximum standardized uptake value (SUVmax), lesion size, and their correlation with serum Tg levels. Results: 18F-FDG PET/CT identified suspicious lesions in 82% of patients, primarily in cervical lymph nodes, lungs, and mediastinum. A total of 104 lesions were detected, with a mean SUVmax of 7.79 ± 5.35. SUVmax values were highest in osseous lesions. A significant positive correlation was found between SUVmax and both lesion size and Tg levels (p < 0.05). Lesion detectability and SUVmax increased with higher Tg levels. Conclusion: 18F-FDG PET/CT demonstrated high sensitivity in detecting recurrent or metastatic disease in TENIS patients. Its diagnostic yield and metabolic activity parameters (SUVmax) increased with serum Tg levels, supporting the clinical value of PET/CT as a preferred imaging modality for guiding further management in this challenging patient group.