Limited value of fluorine-18-fluorodeoxyglucose PET for the differential diagnosis of focal liver lesions in patients with chronic hepatitis C virus infection

Aim: The differentiation of HCC from liver metastasis or benign disorders b y imaging studies based upon morphological aspects may be difficult. Method : In order to evaluate the role of tumour metabolism, we performed FDG-PET (whole-body PET and transmission-corrected regional scans of the liver as w ell as the SUV determined 60 min after injection of FDG) in ten consecutive patients with HCV-associated focal liver lesions. Definite diagnosis was e stablished after ultrasound-guided liver biopsy followed by histopathologic al examination. These results were compared with ultrasound, computed tomog raphy, serum anti-p53, and p53 protein expression. Results: The histologic examination revealed a HCC in five patients, regenerative nodules in three patients, and liver metastasis (primary malignancy: one adenocarcinoma and one neuroendocrine tumour) in the remaining two patients. Three of ten lesi ons were detectable by FDG-PET: two HCCs and one metastatic adenocarcinoma. Seven lesions were not distinguishable by FDG-PET (three HCCs, three regen eration nodules and one metastatic neuroendocrine tumour). In each patient hepatic lesions were visible either by ultrasound or CT. Both tumours(metas tatic adenocarcinoma, moderately well-differentiated HCC) with the stronges t expression of p53 also presented with highly increased FDG uptake. Conclu sions: FDG-PET is not superior to ultrasound or CT and therefore does not a llow the non-invasive differentiation of HCV-associated focal liver lesions . Tissue-diagnosis by means of liver-biopsy followed by histopathological e xamination remains the gold-standard for the differentiation of HCV-related liver lesions The finding of the relationship of p53 protein overexpressio n with the SUV needs further confirmation.