Diagnostic value of F-18 FDG PET/BT in isolated liver masses and the contribution of late imaging to diagnostic accuracy

This study aimed to demonstrate the diagnostic power of Fludeoxyglucose Positron Emission Tomography/Computed Tomography in isolated liver masses that could not be diagnosed with other imaging methods, to examine the relationship between histopathological subtype distributions and the prevalence of the disease focus in the liver, and to determine the changes in quantitative metabolic parameters obtained in early and late images according to the primary disease location and histopathological subtype. Our study was conducted retrospectively and ethics committee approval was obtained. Patients who met the inclusion criteria, were prepared in accordance with the guidelines, and had access to images of evaluable quality were selected. Of the 103 patients included in the study based on clinicopathological evaluation, 91 were diagnosed with malignancy and 12 with benign disease. The sensitivity of Positron Emission Tomography/Computed Tomography in distinguishing benign from malignant was found to be 96.7% and specificity was found to be 91.7%. In 90.1% of patients diagnosed with malignancy, primary disease foci were correctly detected by Positron Emission Tomography/Computed Tomography. When primary liver tumors and metastatic lesions were compared, it was seen that the metastatic group more frequently involved both lobes (p=0.0025) and had a higher number of multiple lesions (p=0.000013). SUVmax and primary lesion index values were significantly higher in the metastatic group compared to primary tumors (p<0.001). SUVmax and primary lesion index values were found to be distinguishable from hepatocellular carcinoma in adenocarcinoma and cholangiocarcinoma lesions and high discrimination power was achieved in ROC analyses (AUC>0.80). In 13 patients who underwent late imaging, an increase in SUVmax (p=0.01) and a decrease in metabolic tumor volume (p<0.001) were detected, and especially the change in total lesion glycolysis showed a significant difference between the metastatic and primary groups (p=0.004). The findings show that Fludeoxyglucose Positron Emission Tomography/Computed Tomography strongly supports the distinction between primary and metastatic in isolated liver masses and that late imaging enhances metabolic characterization. As a result of our study, it is thought that Fludeoxyglucose Positron Emission Tomography/Computed Tomography shortens the diagnostic process and contributes significantly to correct patient management as it provides the opportunity to evaluate wholebody imaging reflecting metabolic changes in a single session.