Shi_2021_Eur.J.Nucl.Med.Mol.Imaging_48_196

PURPOSE: (68)Ga-FAPI-04 is a rapidly evolving PET tracer for whole-body imaging in a variety of cancers. We aimed to evaluate the diagnostic performance of (68)Ga-FAPI-04 for detecting and characterizing hepatic nodules in patients with suspected carcinoma. METHODS: Twenty-five patients showing suspicious hepatic lesions for malignancy underwent (68)Ga-FAPI-04 PET. The maximum and mean standardised uptake values (SUV(max), SUV(mean)) were measured for all detected lesions and normal hepatic tissues, respectively. The target-to-background ratio (TBR) was calculated by dividing the lesion SUV(max) with the SUV(mean) of non-tumour liver tissue. Lesion uptake value was correlated with the in vitro hepatic FAP expression determined by immunohistochemistry (IHC). RESULTS: In total, 17 patients who underwent surgery or biopsy were recruited for the final analysis. A total of 28 intrahepatic malignant lesions were detected in 16 patients; the mean SUV(max) was 8.36 +/- 4.21 (range 2.21 to 15.86), and mean TBR was 13.15 +/- 9.48 (range 2.79 to 38.12) in all detected lesions (n = 28). One benign patient showed negligible hepatic uptake (SUV(max) = 0.47), whereas 75% of the primary intrahepatic hepatocellular carcinoma (HCC) lesions (n = 6) showed prominent FAP expression, 12.5% of the lesions (n = 1) showed moderate expression in stromal cells, and one showed negligible expression. CONCLUSIONS: (68)Ga-FAPI-04 showed high sensitivity in detecting hepatic malignancies, particularly in poorly differentiated forms with concordantly elevated FAP expression.