The aim of this study was to assess and compare fat content within the liver for normal (body mass index
(BMI) < 25 kg/m2), overweight (25-30 kg/m2) and obese (≥ 30 kg/m2) subjects using a noninvasive, non-contrast
computed tomography (CT) quantification method. Adult subjects aged 18-60 yrs scheduled to undergo CT examination
of the abdominal region were recruited for this study, stratified across BMI categories. Liver volume, fat content, and lean
liver volume were determined using CT methods. A total of 100 subjects were recruited, including 30 normal weight, 31
overweight, and 39 obese. Total liver volume increased with BMI, with mean values of 1138 ± 277, 1374 ± 331, and 1766
± 389 cm3 for the normal, overweight, and obese, respectively (P < 0.001), which was due to an increase in both liver fat
content and lean liver volume with BMI. Some obese subjects had no or minimal hepatic fat content. The prevalence of
mild fatty liver in this study of 100 subjects was overestimated for all BMI categories using a range of qualitative
diagnostic measures, with predicted prevalence of fatty liver in obese subjects ranging from 76.9% for liver-to-spleen
ratio ≤ 1.1 to 89.7% for liver attenuation index (liver HU - spleen HU) ≤ 40, compared to 66.7% by quantification of fat
content. Results show that total liver volume increases with BMI, however, not all obese subjects display fatty infiltration
of the liver. CT quantification of liver fat content may be suitable for accurate diagnosis of hepatic steatosis in clinical
practice and assessment of donor livers for transplantation.