Resumen

YAMAGA, Lilian Yuri Itaya et al. 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. Arq Bras Endocrinol Metab [online]. 2007, vol.51, n.4, pp. 581-586. ISSN 0004-2730.  http://dx.doi.org/10.1590/S0004-27302007000400012.

PURPOSE: 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). PATIENTS AND METHOD: PET-CT findings of 25 patients were compared to histopathology evaluation and conventional imaging (CI). RESULTS: 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. CONCLUSION: 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.

Palabras llave : Thyroid gland; PET scan; Carcinoma; Thyroglobulin; Iodine radioisotopes.