Limited Value of Fluorine-18-Fluorodeoxyglucose PET for the Differential Diagnosis of Focal Liver Lesions in Patients with Chronic Hepatitis C Virus Infection

Abstract

Summary Aim: The differentiation of HCC from liver metastasis or benign disorders by 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 well as the SUV determined 60 min after injection of FDG) in ten consecutive patients with HCV-associated focal liver lesions. Definite diagnosis was established after ultrasound-guided liver biopsy followed by histopathological examination. These results were compared with ultrasound, computed tomography, 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 lesions were detectable by FDG-PET: two HCCs and one metastatic adenocarcinoma. Seven lesions were not distinguishable by FDG-PET (three HCCs, three regeneration nodules and one metastatic neuroendocrine tumour). In each patient hepatic lesions were visible either by ultrasound or CT. Both tumours (metastatic adenocarcinoma, moderately well-differentiated HCC) with the strongest expression of p53 also presented with highly increased FDG uptake. Conclusions: FDG-PET is not superior to ultrasound or CT and therefore does not allow the non-invasive differentiation of HCV-associated focal liver lesions. Tissue-diagnosis by means of liver-biopsy followed by histopathological examination remains the gold-standard for the differentiation of HCV-related liver lesions. The finding of the relationship of p53 protein overexpression with the SUV needs further confirmation.