Purpose: To investigate [11C]acetate PET-surrogate parameter of fatty acid synthase activity-as suitable tool for diagnosis and monitoring of liver steatosis.
Methods: In this retrospective study, data were obtained from 83 prostatic carcinoma patients from 1/2008 to 1/2014. Mean HU was calculated from unenhanced CT of all patients from liver with liver HU less than 40 as threshold for liver steatosis. SUVmax of the liver and of the blood pool in thoracic aorta (as background for calculation of a liver/background ratio [SUVl/b]) was measured. t test was used with a P < 0.05 considered as statistically significant difference and ROC analysis was used for calculating specificity and sensitivity.
Results: 19/83 patients (20%) had diagnosis of hepatic steatosis according to CT. Uptake of [11C]acetate was significantly higher in patients with hepatic steatosis as compared to control group (SUVmax 7.96 ± 2.0 vs. 5.48 ± 2.3 [P < 0.001]). There was also a significant correlation between both SUVmax (r = - 0.52, P < 0.001) and SUVl/b (r = - 0.59, P < 0.001) with the density (HU) of the liver. In ROC analysis for detection of liver steatosis SUVmax (threshold: 5.86) had a sensitivity of 94% and specificity of 69% with an AUC of 0.81. Increasing body mass index is correlated with the severity of steatosis.
Conclusion: We showed for the first time that hepatic steatosis associates with increased [11C]acetate uptake. Also, severity of steatosis correlates with [11C]acetate uptake. [11C]acetate uptake PET seems promising for the assessment of liver steatosis.
Keywords: Liver; Liver steatosis; NAFLD; PET; [11C]acetate.