CT indices for the diagnosis of hepatic steatosis using non-enhanced CT images: development and validation of diagnostic cut-off values in a large cohort with pathological reference standard

  • Jieun Byun
  • Seung Soo LeeEmail author
  • Yu Sub Sung
  • Youngbin Shin
  • Jessica Yun
  • Ho Sung Kim
  • Eun sil Yu
  • Sung-Gyu Lee
  • Moon-gyu Lee



To compare the performances of CT indices for diagnosing hepatic steatosis (HS) and to determine and validate the CT index cut-off values.


Three indices were measured on non-enhanced CT images of 4413 living liver donor candidates (2939 men, 1474 women; mean age, 31.4 years): hepatic attenuation (CTL), hepatic attenuation minus splenic attenuation (CTL-S), and hepatic attenuation divided by splenic attenuation (CTL/S). The performances of these CT indices in diagnosing HS, relative to pathologic diagnosis, were compared in the development cohort of 3312 subjects by receiver operating characteristic (ROC) analysis. The cut-off values for diagnosing HS > 33% in the development cohort were determined at 95% specificity and 95% sensitivity using bootstrap ROC analysis, and the diagnostic performance of these cut-off values was validated in the test cohort of 1101 subjects.


CTL-S showed the highest performance for diagnosing HS ≥ 5% and HS > 33% (areas under the curve (AUCs) = 0.737 and 0.926, respectively), followed by CTL/S (AUCs = 0.732 and 0.925, respectively) and CTL (AUCs = 0.707 and 0.880, respectively). For CT scans using 120 kVp, the CTL-S cut-off values for highly specific (i.e., − 2.1) and highly sensitive (i.e., 7.6) diagnosis of HS > 33% resulted in a specificity of 96.4% with a sensitivity of 64.0% and a sensitivity of 97.3% with a specificity of 54.9%, respectively, in the test cohort.


CT indices using liver and spleen attenuations have higher performance for diagnosing HS than indices using liver attenuation alone. The CTL-S cut-off values in this study may have utility for diagnosing HS in clinical practice and research.

Key Points

CT indices based on both liver attenuation and spleen attenuation (CTL-S and CTL/S) have higher diagnostic performance than CTL based on liver attenuation alone in diagnosing HS using various CT techniques.

The CT index cut-off values determined in this study can be utilized for reliable diagnosis or to rule out subjects with moderate to severe HS in clinical practice and research, including the selection of living liver donors and the development of cohorts with HS or healthy controls.


Fatty liver Non-alcoholic fatty liver disease Tomography, X-ray computed 



Areas under the receiver operating characteristic curve


Confidence interval


Computed tomography


Hepatic attenuation


Hepatic attenuation minus splenic attenuation


Hepatic attenuation divided by splenic attenuation


Hepatic steatosis


Non-alcoholic fatty liver disease


Receiver operating characteristic


Region of interest



This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT, and Future Planning (NRF-2017R1A2B4003114), the Bio and Medical Technology Development Program of the NRF funded by the Ministry of Science and ICT (NRF-2016M3A9A7918706), a grant from the Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI), funded by the Ministry of Health & Welfare, Republic of Korea (grant number: HI18C2383), and a grant (2014-444) from the Asan Institute for Life Sciences, Asan Medical Center, Seoul, Korea.

Compliance with ethical standards


The scientific guarantor of this publication is Seung Soo Lee.

Conflict of interest

The authors of this manuscript declare no relationships with any companies, whose products or services may be related to the subject matter of the article.

Statistics and biometry

One of the authors has significant statistical expertise.

Informed consent

Written informed consent was waived by the institutional review board.

Ethical approval

Institutional review board approval was obtained.


• retrospective

• diagnostic or prognostic study

• performed at one institution

Supplementary material

330_2018_5905_MOESM1_ESM.docx (1.2 mb)
ESM 1 (DOCX 1258 kb)


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Copyright information

© European Society of Radiology 2018

Authors and Affiliations

  • Jieun Byun
    • 1
  • Seung Soo Lee
    • 1
    Email author
  • Yu Sub Sung
    • 1
  • Youngbin Shin
    • 1
  • Jessica Yun
    • 1
  • Ho Sung Kim
    • 1
  • Eun sil Yu
    • 2
  • Sung-Gyu Lee
    • 3
  • Moon-gyu Lee
    • 1
  1. 1.Department of Radiology and Research Institute of Radiology, Asan Medical CenterUniversity of Ulsan College of MedicineSeoulSouth Korea
  2. 2.Department of Diagnostic Pathology, Asan Medical CenterUniversity of Ulsan College of MedicineSeoulSouth Korea
  3. 3.Division of Hepatobiliary Surgery and Liver Transplantation, Department of SurgeryUniversity of Ulsan College of MedicineSeoulSouth Korea

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