Prognostic Value of Dual-Energy CT Liver Fat Fraction in Critically Ill Patients

Overview

This study evaluated liver fat fraction (FF) using dual-energy CT (DECT) in critically ill ICU patients and its association with clinical outcomes. Liver DECT FF was quantified at two time points, revealing changes over ICU stay and correlations with mortality, ICU scores, and length of stay.

Background

Liver steatosis, defined as fat accumulation in over 5% of hepatocytes, is increasingly prevalent in ICU patients and contributes to morbidity and mortality. Traditional liver function tests do not reliably identify steatosis, and liver biopsy is often contraindicated in critically ill patients. Imaging modalities like ultrasound and MRI have limitations in the ICU setting, whereas DECT offers contrast-independent quantification of liver fat. Understanding liver fat dynamics and prognostic implications in ICU patients remains an unmet clinical need.

Data Highlights

Key Findings

• Liver DECT FF can be reliably quantified in critically ill patients despite contrast administration using virtual non-contrast imaging.
• Liver fat fraction changes over time during ICU stay, indicating dynamic alterations in hepatic steatosis in immobilized patients.
• Higher liver DECT FF is associated with increased in-hospital mortality and correlates with established ICU prognostic scores such as SAPS II and SOFA.
• Conventional CT body composition parameters, including skeletal muscle index and adipose tissue areas, complement liver FF assessment for nutritional and prognostic evaluation.
• Inter-observer variability for liver DECT FF quantification is low, supporting reproducibility of this imaging biomarker.

Clinical Implications

DECT-derived liver fat fraction offers a non-invasive, contrast-independent method to assess hepatic steatosis in critically ill patients, overcoming limitations of conventional imaging and biopsy. Monitoring liver FF changes may help identify patients at higher risk of adverse outcomes and guide nutritional and therapeutic interventions. Incorporating liver FF quantification with other CT body composition metrics can enhance comprehensive ICU patient assessment.

Conclusion

Dual-energy CT enables precise quantification of liver fat fraction in critically ill patients and provides prognostic information linked to mortality and ICU severity scores. This imaging biomarker holds promise for improving liver dysfunction evaluation and outcome prediction in the ICU setting.

References

1. Erley et al 2024 -- Muscular DECT Fat Fraction in ICU Patients
2. Gomez-Perez et al -- CT Body Composition Analysis
3. SAPS II Score -- Le Gall et al 1993
4. SOFA Score -- Vincent et al 1996
5. Charlson Comorbidity Index -- Charlson et al 1987