Gía trị của 18FDG PET/CT và CT ở bệnh nhân ung thư tuyến giáp biệt hóa có nồng độ Thyroglobulin huyết thanh cao và xạ hình toàn thân với 131I âm tính

Value of PET /CT and diagnostic CT scan in differentiated thyroid carcinoma patients with high serum thyroglobulin and negative 131I whole body scan

SUMMARY:

Objective: to determine value of FDG-PET/CT and diagnostic CT scan in post-surgical differentiated thyroid carcinoma patients with high serum thyroglobulin and negative 131I whole body scan.

Patients and method: We performed FDG-PET/CT and diagnostic CT scan in 49 post-surgical differentiated thyroid carcinoma patients with high serum thyroglobulin and negative 131I whole body scan who already underwent 131I therapy in Department of Nuclear Medicine, 108 Central Military Hospital.

Results: 41 lesions detected in 29/49 patients (59.2%) with positive PET/CT scan compared to only 20 lesions 18/49 patients (36.7%) detected on positive CT scan. The Sn, Ac and NPV of FDG-PET/CT were 83.9%, 83.7% and 75% higher than those of CT (51.6%, 65.3% and 51.6%, respectively). Sp and PPV of FDG-PET/ CT (83.3% and 89.7%, respectively) were similar to those of CT (88.9%). SUVmax thresholds with good diagnostic value were 4.5 ( Sn 84.6%, Sp 66.7%) and 5.0 ( Sn 65.3%, Sp 100%). FDG-PET/CT had altered treatment plan in 25/49 patients (51.2%).

Conclusion: FDG-PET/CT is superior than CT in detecting reccurent/metastatic lesions in post-surgical differentiated thyroid carcinoma patients with high serum thyroglobulin and negative 131I whole body scan.

Key words: FDG PET/CT, CT, differentiated thyroid carcinoma