Evaluation of hepatic metabolic activity in non-alcoholic fatty livers on 18FDG PET/CT

The liver has been used as a reference organ for the assessment of abnormal (18)F-fluoro-2-deoxy-d-glucose ((18)FDG) in the body. Some researchers found that hepatosteatosis significantly changed the hepatic (18)FDG uptake, while others did not. This study investigated whether the liver's (18)FDG uptake was affected by the diffuse fatty infiltration of the liver.

A total of 156 cases were included in this study. Different patient groups were defined according to the liver Hounsfield unit (HU). The HU was calculated from an unenhanced CT, for all patients, and we calculated the mean standardized uptake value (SUVmean) and maximum standardized uptake value (SUVmax) on an (18)FDG PET scan. For this purpose, we placed regions of interest (ROIs) on the liver image. We statistically compared the SUVmean and SUVmax measured in the fatty liver patients and the control group.

The average SUVmean and SUVmax values were calculated as 2.58±0.66 and 3.94±1, respectively, in the patient group and 2.54±0.57 and 3.7±0.88, respectively, in the control group. We found the average SUVmean and SUVmax values in the fatty liver group and its subsets were not significantly different from the values in the control group (p>0.05). We also did not find any statistically significant correlation between average liver density (HU) and the average SUV values (p>0.05).

Fatty infiltration may not have a significant effect on the liver's (18)FDG uptake. Thus, the liver may be used as a reference or comparator on (18)FDG PET scans in patients with fatty liver disease.