Comparison of PET-CT findings with histopathologic results of patients with solitary pulmonary nodules

ABSTRACT Comparison of PET-CT Findings With Histopathologic Results Of Patients With Solitary Pulmonary Nodules Purpose: Solitary pulmonary nodules (SPNs) are usually detected icncidentally on chest radiographs. The etiology of and diagnostic approaches to SPNs differs between various countries. Since various benign and malign, especially early stage of lung cancer, etiologies are responsible for SPN, iIt is very important to evaluate any SPN, detected at chest radiographs. PET-CT, which is being used within the recent years, has an important contributions on differential diagnosis of benign or malign nodules, solving the etiology of SPN. In this study, we aimed to compare the SUV-max values of solitary pulmonary nodules on PET-CT evaluation with histopathological results. Material and Methods: In this study, 600 patients, admitted to Pulmonology Department of Cukurova University Medical Faculty between January 2011 and January 2014, were retrospectively analyzed. Among them, 110 (%18,3) patients with SPN which were diagnosed with chest computed tomography and diagnosed histopathologically were included in the study for evaluation. The SUV-MAX values on PET-CT and histopathological results were compared statistically. PET-CT was performed "Siemens, Biograph 6, HI-REZ, USA" brand machine in Nuclear Medicine Department of Cukurova University. The limit of SUV-max value for malignancy was accepted as ≥ 2.5, found on the study of Duhaylongsod et al. Findings: Among 110 patients of our study, 90 (81.8%) were male patients, 20 (18.2%) were female patients. The median age (min-max) was found 62 (34-83). Histopathologicallly, 72 cases were malign and 28 cases were benign etiology. The median SUV-max value for malignant nodules (min-max) was found 10.15 (1.1-34.5), and the median SUV-max value for benign nodules was found 1.85 (0.0-9.7), (p=0.0001). Adenocarcinoma (41.7%) was the most common subtype among all 72 malignant histopathologies. Of 72 malign cases, the SUV-max ≥2.5 was detected in 69 patients (95.8%). Of 38 benign cases, the SUV-max ≥2.5 was detected in 13 patients (34.2%) (p=0.0001) (sensitivity: %68.4, specifity: %95.8). On ROC analysis depending on various SUV-max values detecting malignancy; at the value of SUV-max ≥ 3.7, the sensitivity (%82) and the specifity (%90) value were found to be the most significant. Conclusion: Although SUV-max ≥2.5 was considered as reference value for detecting malignancy in various studies, SUV-max ≥ 3.7 was found to be more valuable for detecting malignancy in our study. However, we think that high values for SUV-max can be detected on lesions with tuberculosis at prevalent countries, like Turkey and should be taken in account in the differential diagnosis of SPN. Key Words: Solitary Pulmonary Nodule, PET-CT, SUV/max, Benign Malign