[The values of (11)C-acetate and (18)F-fluorodeoxyglucose positron emission tomography in diagnosis of indefinite liver masses].

OBJECTIVE: To evaluate the values of the two tracers of positron emission tomography (PET) in the liver masses not definitely diagnosed by routine examinations. METHODS: Fifteen patients with liver masses of indefinite diagnosis after serum tests and common imaging examinations underwent PET with both (11)C-acetate and (18)F-fluorodeoxyglucose (FDG). The results were compared. After the PET all 15 patients were subjected to surgery. RESULTS: Pathological examination showed that 13 of the 15 patients were confirmed as malignant liver lesions and the other 2 as benign. Within the 13 malignant liver lesions, (11)C-acetate-PET suggested malignancy in 10 cases, and benignancy in 3 cases. And (18)F-FDG-PET suggested malignancy in 9 cases and benignancy in 4 cases. In the two benign cases, both (11)C-acetate-PET and (18)F-FDG-PET showed one malignant liver lesion and one benign liver lesion. (11)C-acetate-PET showed a high sensitivity (100%) for the well-differentiated tumors, and (18)F-FDG-PET showed a high sensitivity for the poorly-differentiated tumors. CONCLUSION: The diagnostic accuracy for liver lesions may be improved by the two tracers of PET when the lesions can not be definitely diagnosed by routine examinations and at the same time when the patients are able to afford two PET examinations. They may also imply the cell-differentiation of the liver masses, and be helpful for selecting the treatment means for the patients.