Clinical usefulness of positron emission tomography with fluorine-18-fluorodeoxyglucose in the diagnosis of liver tumors

We studied various liver tumors by positron emission tomography with fluori ne-18 fluorodeoxyglucose (FDG-PET) to examine the diagnostic usefulness of this technique. We also examined the relation between findings on FDG-PET a nd the characteristics of hepatocellular carcinoma. FDG-PET was performed in 78 patients with liver tumors, including 53 with p rimary liver cancer [48 hepatocellular carcinomas (HCC) and 5 cholangiocell ular carcinomas (CCC)], 20 with metastatic liver cancer, 2 with liver heman gioma, and 3 with focal nodular hyperplasia. For quantitative evaluation, a region of interest (ROI) was placed over the entire tumor region, at the l evel of the maximum diameter of the tumor. A background ROI was then placed over the non-tumor region of the liver. The average activity within each R OI was subsequently corrected for radioactive decay, and the standardized u ptake value (SUV) was calculated by dividing the tissue activity by the inj ected dose of radioactivity per unit body weight. SUV ratio was expressed a s the tumor-to-non-tumor ratio of the SUV. The median SW was significantly lower in HCC than in metastatic live cancer or CCC, and the median SUV ratio was significantly lower in HCC than in me tastatic liver cancer or CCC. The median SUV was not higher in multiple HCC than in single HCC, but the median SUV ratio was significantly higher in m ultiple HCC than in single HCC. The median SUV and the median SUV ratio wer e significantly higher in the presence of portal vein thrombosis than in th e absence of such thrombosis. The Cancer of the Liver Italian Program score and the a-fetoprotein value correlated significantly with both the SW and SW ratio. These results suggest that FDG-PET is clinically useful not only for the differential diagnosis of liver tumors but also for evaluation of t he clinical characteristics of HCC.