Diagnostic value of positron emission tomography/computed tomography with fluorine-18 fluordeoxyglucose in patients with differentiated thyroid gland carcinoma, high thyroglobulin serum levels and negative iodine whole body scan

• Published in: Arquivos brasileiros de endocrinologia e metabologia Vol. 51; no. 4; pp. 581 - 586
• Main Authors: Yamaga, Lilian Yuri Itaya, Cunha, Marcelo Livorsi da, Wagner, Jairo, Thom, Annelise Fischer, Daniel, Mauro Miguel, Funari, Marcelo B de Gusmão
• Format: Journal Article
• Language: Portuguese
• Published: Brazil 01.06.2007
• Subjects: Adolescent; Adult; Aged; Biomarkers, Tumor; Carcinoma, Medullary - diagnostic imaging; Carcinoma, Medullary - prevention & control; Female; Fluorodeoxyglucose F18; Humans; Male; Middle Aged; Neoplasm Recurrence, Local - diagnostic imaging; Positron-Emission Tomography - methods; Radiopharmaceuticals; Sensitivity and Specificity; Thyroglobulin - blood; Thyroid Neoplasms - diagnostic imaging; Thyroid Neoplasms - prevention & control; Tomography, X-Ray Computed - methods; Whole Body Imaging
• ISSN: 0004-2730
• DOI: 10.1590/S0004-27302007000400012

To evaluate the role of PET-CT with FDG-18F in the detection of recurrence and/or metastasis of differentiated thyroid carcinoma (DTC) in patients with elevated levels of thyroglobulin (TG) and negative whole body scan (WBS). PET-CT findings of 25 patients were compared to histopathology evaluation and conventional imaging (CI). PET-CT scan was positive in 16 patients finding 14 true-positive and 2 false-positive cases (positive predictive value 87.5%). Nine patients had negative PET-CT; two had decrease of TG to undetectable levels. One patient had residual disease detected by post-therapeutic WBS. Six patients had no evidence of tumor during follow-up (mean time 16 months). PET-CT was concordant with CI in 52%, partially concordant in 12% and discordant in 36% (6 false-negatives and 3 false-positive of CI). We observed a tendency of increasing proportion of positive PET-CT with increasing TG. PET-CT scan with FDG-18F is useful in the detection of recurrence and/or metastases of DTC with high TG levels but negative WBS. It presents elevated positive predictive value and is superior to CI being more effective as higher the serum TG levels.