Noninvasive Quantification of Hepatic Steatosis: Relationship Between Obesity Status and Liver Fat Content

S. C. McLeay1, 2, G. A. Morrish2, T. K. Ponnuswamy3, B. Devanand3, M. Ramanathan4, L. Venkatakrishnan3, S. Ramalingam3, B. Green2, *
1 School of Pharmacy, The University of Queensland, Brisbane, Queensland, Australia
2 Model Answers Pty Ltd, Brisbane, Queensland, Australia
3 PSG Institute of Medical Sciences and Research, Coimbatore, India
4 PSG College of Pharmacy, Coimbatore, India

© 2014 McLeay et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at the Model Answers Pty Ltd, Level 5, 99 Creek St, Brisbane, Qld, Australia, 4000; Tel: +61 7 3221 1315; Email:


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.

Keywords: Body mass index, computed tomography, fatty liver, hepatic steatosis, obesity.