ĐẶC ĐIỂM HÌNH ẢNH XẠ HÌNH SPECT/CT VỚI I-131 TRÊN BỆNH NHÂN UNG THƯ TUYẾN GIÁP THỂ BIỆT HÓA CÓ NGUY CƠ TÁI PHÁT CAO

Abstract

Objective: To describe the imaging characteristics of I-131 SPECT/CT and compare it with planar whole-body scintigraphy (WBS) in patients with high-risk differentiated thyroid carcinoma (DTC). Methods: This prospective descriptive study included 125 patients diagnosed with differentiated thyroid carcinoma (DTC), who had undergone total thyroidectomy and were classified as high-risk for recurrence according to the American Thyroid Association (ATA) 2015 risk stratification guidelines. All patients underwent WBS combined with SPECT/CT both before and after I-131 therapy. Results: Pre-treatment SPECT/CT detected 308 areas of increased radioactive uptake (IRU). Among these, 291 lesions were located in the neck, with 57 identified as metastatic lymph nodes (18.5%). Of the 228 lesions classified by WBS as residual thyroid tissue, SPECT/CT reclassified 21 of these as metastatic lymph nodes (9.2%). SPECT/CT altered the diagnosis in 72 lesions (24.3%), including upstaging in 57 lesions (19.3%). Out of the 35 patients with metastasis (28.0%), 31 had cervical lymph node metastasis, and 3 had distant metastasis. Post-treatment SPECT/CT identified an additional 36 IRU sites compared to pre-treatment imaging, including 4 distant metastases and 17 lymph node metastases. When compared to post-treatment WBS, SPECT/CT identified 2 additional IRU sites, excluded 1 suspicious metastasis, and modified the diagnosis in 15 out of the 35 newly detected lesions on WBS (42.9%), with upstaging in 12 lesions (34.3%). Conclusion: Compared to WBS, I-131 SPECT/CT imaging both before and after therapy significantly enhances the detection of areas with increased radioactive uptake, including metastatic lymph nodes, distant metastases, and additional confirmation of remaining thyroid tissue, as well as physiological uptake in certain organs.