Compari̇son of [18f]FDG PET/CT and other imaging modalities in diagnosis of primary liver malignancies: [18f]FDG PET/CT, [68GA]-fapi-04 PET/CT and MRİ

Purpose: Primary liver malignancies are third leading cause of cancer related death worldwide. Early diagnosis is essential to achieve curative treatment in and accurate staging is important for treatment selection and determining prognosis. Aim of this study is to evaluate the diagnostic value of F18-FDG PET/CT and Ga68-FAPI PET/CT in primary liver malignancies, and correlate PET/CT parameters with laboratory and histopathology findings. Material-Method: Patients who underwent 18F-FDG PET/CT imaging with suspected or known primary liver malignancies and had MRI and/ or histopathological confirmation were evaluated and 32 patients who underwent 68Ga FAPI PET/CT in one week were enrolled in the study. Gold standard was MRI and histopathology. Diagnostic values of both PET/CT calculated as lesion based. Standard uptake value max (SUVmax) of lesions, standard uptake value mean (SUVmean) of normal liver and tumor/background rate (TBR= SUVmax/SUVmean) values also compared. Results: There were 18 (%56,2) male and 14 (%43,8) female in this study (Median age: 59.2±12.8 years). Eighteen patients had intrahepatic cholangiocarcinoma (ICC), 14 had hepatocellular carcinoma (HCC). Of 32 patients 28 had MRI and 20 had histopathological confirmation. 68Ga-FAPI PET/CT showed higher sensitivity and specificity than 18F-FDG PET/CT(%83,3, %50 vs %57,4, %40, respectively). In metastatic lesions 68Ga-FAPI PET/CT also showed higher sensitivity than 18F-FDG PET/CT (%96,7 vs %54,9). In ICC group 68Ga-FAPI PET/CT showed higher sensitivity and specificity than 18F-FDG PET/CT (%92,5, %50 vs %48,1, %25). But in HCC group diagnostic values were comparable (%74,0, %50 vs %66,6, %100). Median SUVmax and TBR values were higher at 68Ga-FAPI PET/CT than 18F-FDG PET/CT in all primary liver lesions (12,6 vs 6,8 p<0,001; 6,2 vs. 3,6 p:0,001) and ICC lesions. Median SUVmax of metastatic lesions were also higher on 68Ga-FAPI PET/CT (10,5 vs. 5,2 p:0,02). Conclusion: 68Ga-FAPI PET/CT showed better diagnostic values than 18F-FDG PET/CT in primary liver malignancies, particularly in ICC. Usage of 68Ga-FAPI PET/CT may improve tumor staging, and implementation of necessary treatment modifications including theranostic applications.