Rafael de Castro Martins, Sérgio Altino de Almeida,
Antônio Alexandre de Oliveira Siciliano, Maria Carolina Pinheiro Pessoa Landesmann,
Fabrício Braga da Silva, Carlos Alberto de Barros Franco, Lea Mirian Barbosa da Fonseca
Objective: To determine the diagnostic accuracy of positron emission tomography/computed tomography (PET/CT) using fluorine-
18‑deoxyglucose ([18F]-FDG) for the evaluation of a solitary pulmonary nodule (SPN). Methods: Prospective analysis of 53 consecutive
patients submitted to PET/CT between March 2005 and May 2007 for the evaluation of an SPN. Of those, 32 met the criteria for inclusion
in the present study. The lesions were evaluated for location, size, radiotracer uptake and maximum standardized uptake value (SUV). The
FDG-PET/CT results were correlated with other predictors of malignancy (age, gender, smoking status, nodule size and nodule location). The
definitive diagnosis was established through histopathology or through clinical/radiological follow-up for at least one year. Results: Fourteen
malignant SPNs were found. Through analysis of the receiver operating characteristic curve, we established an SUV of 2.5 as the most
appropriate cut-off point, since it correctly identified 13 of the 14 malignant SPNs. The results below that point revealed one false positive
for neoplasia out of a total of 14. The semiquantitative method presented a sensitivity of 92.9%, specificity of 72.2%, positive predictive
value of 72.2%, negative predictive value of 92.9% and accuracy of 81.2%. The multivariate analysis showed a statistically significant
association with SPN malignancy only for nodule location in the upper lobes (p = 0.048) and SUV (p = 0.007). Conclusions: The results
obtained suggest that the SUV of [18F]-FDG is a useful predictor of neoplasia in SPN, with a high negative predictive value, which allows
malignancy to be safely ruled out, showing its relevance in the diagnostic approach to pulmonary nodules.
Keywords: Positron-emission tomography; Coin lesion, pulmonary; Lung neoplasms.