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Ultrasound-estimated hepatorenal index: diagnostic performance and interobserver agreement for pediatric liver fat
Farid Hajibonabi1, Erica L Riedesel2, Susan D Taylor2
1Department of Radiology & Imaging Sciences, Emory University and Children's Healthcare of Atlanta, 1405 Clifton Road NE, Atlanta, GA, 30322, USA. farid.hajibonabi@emory.edu.
Insights
Ultrasound
Area of Science:
- Radiology and Imaging
- Pediatric Gastroenterology
- Hepatology
Background:
- Nonalcoholic fatty liver disease (NAFLD) is a growing concern in children.
- Semiquantitative and quantitative sonographic techniques show promise for NAFLD screening and surveillance in pediatric populations.
- Accurate liver fat quantification in children is crucial for early detection and management.
Purpose of the Study:
- To evaluate the diagnostic performance and interobserver agreement of the hepatorenal index (HRI) for quantifying liver fat in children using ultrasound.
- To compare ultrasound-derived HRI with magnetic resonance imaging (MRI) proton density fat fraction (PDFF) as the reference standard.
- To determine an optimal HRI cutoff value for diagnosing pediatric hepatic steatosis.
Main Methods:
- A retrospective study included 41 children (<18 years) who underwent both abdominal ultrasound and MRI for liver fat quantification between April 2014 and April 2023.
- Three blinded readers assessed subjective hepatic steatosis and calculated HRI from ultrasound images.
- MRI PDFF served as the reference standard; interobserver agreement, correlation with PDFF, and optimal HRI cutoff via ROC analysis were performed.
Main Results:
- The study included 41 children (25 male, median age 13 years) with a median MRI PDFF of 11.30%.
- Interobserver agreement for HRI was moderate (ICC=0.61).
- Moderate correlation was found between HRI and MRI PDFF (r=0.62-0.67). An HRI cutoff of 1.99 demonstrated high accuracy (89% sensitivity, 93% specificity) for diagnosing hepatic steatosis.
Conclusions:
- Ultrasound-derived hepatorenal index (HRI) shows moderate interobserver agreement and correlation with MRI-derived proton density fat fraction (PDFF) in pediatric liver fat quantification.
- An HRI cutoff value of 1.99 is effective in accurately identifying hepatic steatosis in children.
- Ultrasound, particularly using HRI, offers a viable tool for pediatric liver fat assessment.
Background:
Semiquantitative and quantitative sonographic techniques have the potential for screening and surveillance of children at risk of nonalcoholic fatty liver disease.
Objective:
To determine diagnostic performance and interobserver agreement of hepatorenal index (HRI) for pediatric ultrasound-based liver fat quantification.
Materials And Methods:
In an institutional review board (IRB)-approved retrospective study (April 2014 to April 2023), children (< 18 years) with clinically performed magnetic resonance imaging (MRI) scans for liver fat quantification were assessed. Inclusion criteria required availability of abdominal ultrasound within 3 months of quantitative MRI. Three blinded readers subjectively assessed for sonographic hepatic steatosis and calculated HRI. MRI proton density fat fraction (PDFF) was the reference standard. Interobserver agreement, correlation with PDFF, and optimal HRI (using ROC analysis) values were analyzed. The significance level was set at p < 0.05.
Results:
A total of 41 patients (25 male) with median (interquartile range (IQR)) age of 13 (10-15) years were included. Median (IQR) MRI PDFF was 11.30% (2.70-17.95%). Hepatic steatosis distribution by MRI PDFF included grade 0 (34%), grade 1 (15%), grade 2 (22%), and grade 3 (29%) patients. Intraclass correlation coefficient for HRI among the three readers was 0.61 (95% CI 0.43-0.75) (p < 0.001). Moderate correlation was observed between manually estimated HRI and PDFF for each reader (r = 0.62, 0.67, and 0.67; p < 0.001). Optimal HRI cutoff was found to be 1.99 to diagnose hepatic steatosis (sensitivity 89%, specificity 93%). Median (IQR) HRI for each MRI grade of hepatic steatosis (0-4) was as follows: 1.2 (1.1-1.5), 2.6 (1.1-3.3), 3.6 (2.6-5.4), 5.6 (2.6-10.9), respectively (p < 0.001).
Conclusion:
Ultrasound-estimated HRI has moderate interobserver agreement and moderate correlation with MRI-derived PDFF. HRI of 1.99 maximizes accuracy for identifying pediatric liver fat.
