Clinical and histopathologic features of chronic liver disease associated with hepatic fluorine-18 fluorocholine uptake

Objectives: Phosphatidylcholine (PtC) is used by hepatocytes in the course of liver regeneration as well to produce lipid particles and bile. Fluorine-18 fluorocholine (18F-choline) allows PET/CT to depict the initial steps of PtC synthesis. We conducted a radiopathologic correlation study to identify histopathological features of chronic liver disease potentially associated with changes in 18F-choline uptake in the liver.

Methods: Thirty-five patients with primary liver cancer who were candidates for hepatic resection or liver transplant underwent pre-operative imaging of the liver with 18F-choline PET/CT. Static liver images were acquired at approximately 30 minutes post-injection. Standardized uptake value (SUV) measurements corresponding to native liver tissue were obtained from a 4cm diameter region of interest in the tumor-bearing hepatic lobe and compared to clinical and histopathologic indices of chronic liver disease, including AST-to-platelet ratio index (APRI), Model for End-stage Liver Disease (MELD) score, Albumin-Bilirubin Index (ALBI), Knodell Histologic Activity Index (HAI) and METAVIR scores.

Results: Liver mean SUV (mean ± SD 7.9 ± 1.6) correlated significantly with HAI, METAVIR activity and fibrosis scores, APRI, and ALBI, but not MELD or Child-Pugh scores (Table 1). There were significant differences in liver mean SUV between patients stratified histologically by degree of portal inflammation (p = 0.0001), piecemeal necrosis, (p=0.0002), and fibrosis (p=0.0085), but not lobular inflammation (p = 0.1351). The area under the ROC curve for detection of fibrosis (METAVIR F1-F4) was 0.83. There was a significant difference in liver mean SUV between HCV and HBV infected patients (6.7 vs 8.8, p = 0.0036). No significant effects of steatosis, hypertension, diabetes mellitus, or hyperlipidemia on liver mean SUV were observed. There were no significant differences in mean liver SUV or HAI across gender or cancer type.

Conclusion: Liver uptake of 18F-choline appears correlated with histopathologic features of chronic liver disease, including fibrosis, inflammation, and necrosis. These preliminary findings may support further research on 18F-choline PET/CT as an imaging modality for spatially assessing liver fibrosis and inflammation. Research Support: This work was supported by NIH/NCI grant R01CA161209-06.