Positron emission tomography scanning in the evaluation of hepatocellular carcinoma

Background/Aims: F-18-fluorodeoxyglucose uptake allows estimation of glucos e metabolism by tumor cells using positron emission tomography (PET), We ev aluated the role of PET imaging in the diagnosis of hepatocellular carcinom a. Methods: PET images were collected after intravenous injection of 8-12 mCi of F-18-FDG in 20 patients with hepatocellular carcinoma (HCC), PET tumor a ctivity level was assessed on a scale of 1 to 4 compared to normal liver ti ssue. The PET score was compared with abdominal computerized tomography (CT ) scan results and between tumors of different grades and differentiation. Results: Of the 20 patients studied, 11 (55%) had positive PET scans (PET s core: 3 or 4) while nine (45%) were negative (PET score: 1 or 2), CT scan w as positive in 18 patients (90%) and negative in two (10%), PET, however, r evealed metastases in three patients that were not seen on CT. On pathologi cal review, well-differentiated and low-grade tumors had lower PET scores. Comparison of the well-differentiated with the moderately- and poorly-diffe rentiated tumors revealed a statistically significant difference. No statis tical significance was observed between the moderately- and poorly-differen tiated tumors or between different tumor grades and PET scores, Conclusions: The sensitivity of PET in diagnosis of HCC was 55% compared to 90% for CT scanning, although only PET detected some tumors (including dis tant metastases), Well-differentiated and low tumor grades had lower activi ty on PET and correspondingly lower PET scores. PET imaging may help assess tumor differentiation and may be useful in the diagnosis and staging and p rognostication of HCC as an adjunct to CT.