[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].
OBJECTIVE
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).


METHODS
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.


CONCLUSIONS
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.
Departamento de Imagem, Hospital Israelita Albert Einstein 701, 05651-901 São Paulo, SP. itaya@einstein.br
Lilian Yuri Itaya
LY
Yamaga
Marcelo Livorsi da
ML
Cunha
Jairo
J
Wagner
Annelise Fischer
AF
Thom
Mauro Miguel
MM
Daniel
Marcelo B de Gusmão
MB
Funari
D000293:Adolescent; D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor; D018276:Carcinoma, Medullary / Q000000981:diagnostic imaging* / Q000517:prevention & control; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D012680:Sensitivity and Specificity; D013954:Thyroglobulin / Q000097:blood*; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging* / Q000517:prevention & control; D014057:Tomography, X-Ray Computed / Q000379:methods*; D051598:Whole Body Imaging
D014408:Biomarkers, Tumor; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D013954:Thyroglobulin