Diagnostic value of PET/CT in differentiating benign from malignant solitary pulmonary nodules

Solitary pulmonary nodules (SPNs) are round or oval lesions with a clear border with the surrounding parenchymal tissue and a radiologic diameter smaller than 3 cm which are not associated with atelectasis, pneumonia, lymphadenopathy, or chest wall pathologies. The purpose of the present study was to evaluate the efficacy of positron emission tomography (PET) / computerized tomography (CT) in differentiating benign from malignant SPNs.

In this retrospective study, 209 patients, who were diagnosed with SPN by thoracic CT and demonstrated positive or negative results for malignancy in the PET/ CT examination between January 2007 and June 2010, were enrolled. Among the 91 patients who gave consent for interventional procedures, performed were bronchoscopic endobronchial biopsy in 10, transbronchial biopsy in 15, bronchoscopic brushing in 4, transthoracic needle biopsy in 11, video-assisted thoracoscopy (VATS) in 4, lobectomy in 22, pneumonectomy in 2, and wedge resection in 23. The materials were histopathologically examined.

129 (61.72%) of the SPN cases were benign and 80 (38.27%) malignant. The mean SUVmax value for the benign SPNs was 2.06 ± 3.29 and 7.39±5.69 for the malignant SPNs (p=0.000). Positive correlation was found between the nodule diameter and risk for malignancy. A SUVmax value of 4 was found to have the best sensitivity and specificity.

PET/CT was shown to be an accurate method in the differential diagnosis of benign from malignant solitary pulmonary nodules.