CT Hepatic Steatosis Fat Fraction Calculator

Interpretation Guide

• Normal: <5% fat fraction
• Mild Steatosis: 5-15% fat fraction
• Moderate Steatosis: 15-20% fat fraction
• Severe Steatosis: >20% fat fraction

Important Notes

• The unenhanced CT formula (MRI-PDFF(%) = -0.58 × CT(HU) + 38.2) applies to scans at 120 kVp
• Post-contrast interpretation is most accurate for moderate to severe steatosis
• In contrast studies, liver attenuation alone is more reliable than liver-spleen difference
• Arterial phase imaging may lead to misdiagnosis; portal venous phase is preferred

References

1. Stocker D, Haslebacher M, Manoliu A, Schulze BD, Hasse B, Inderbitzin D, et al. Quantification of Liver Fat Content with CT and MRI: State of the Art. Radiology. 2021 Nov;301(2):250-62.
2. Pickhardt PJ, Park SH, Hahn L, Lee SG, Bae KT, Yu ES. Specificity of unenhanced CT for non-invasive diagnosis of hepatic steatosis: implications for the investigation of the natural history of incidental steatosis. Eur Radiol. 2012 May;22(5):1075-82.
3. Kodama Y, Ng CS, Wu TT, Ayers GD, Curley SA, Abdalla EK, et al. Comparison of CT methods for determining the fat content of the liver. AJR Am J Roentgenol. 2007 May;188(5):1307-12.
4. Lee SS, Park SH, Kim HJ, Kim SY, Kim MY, Kim DY, et al. Non-invasive assessment of hepatic steatosis: prospective comparison of the accuracy of imaging examinations. J Hepatol. 2010 Apr;52(4):579-85.
5. van Werven JR, Marsman HA, Nederveen AJ, Smits NJ, ten Kate FJ, van Gulik TM, et al. Assessment of hepatic steatosis in patients undergoing liver resection: comparison of US, CT, T1-weighted dual-echo MR imaging, and point-resolved 1H MR spectroscopy. Radiology. 2010 Jul;256(1):159-68.

Disclaimer: The author makes no claims of the accuracy of the information contained herein; this information is for educational purposes only and is not a substitute for clinical judgment.