Ultrasound-based steatosis grading system using 2D-attenuation imaging: an individual patient data meta-analysis with external validation
Author Block: C. Hobeika1, M. Ronot1, D. Valla1, J. M. Correas2, V. Vilgrain1, M. Dioguardi Burgio1; 1Clichy/FR, 2Paris/FR
Purpose: Non-invasive tools assessing steatosis, such as ultrasonography-based 2D-attenuation imaging (ATI), are needed to tackle the worldwide burden of NAFLD. This one-stage individual patient data (IPD) meta-analysis aimed to create an ATI-based steatosis grading system.
Methods or Background: A systematic review (EMBASE+MEDLINE, 2018-2022) identified studies, including patients with histologically or MRI-PDFF-verified ATI values for grading steatosis (S0 to S3). One-stage IPD meta-analyses were conducted using generalised mixed models with a random study-specific intercept. Created ATI-based steatosis grading system (aS0 to aS3) was externally validated on a prospective cohort of patients with type 2 diabetes and NAFLD (n=174, histologically and MRI-PDFF verified steatosis).
Results or Findings: Eleven enrolled studies included 1374 patients, classified into S0, S1, S2, and S3 in 45.4%, 35.0%, 9.3%, and 10.3% of the cases. ATI was correlated with histologically (r=0.60; 95%CI: 0.52,0.67; p<0.001), and MRI-PDFF (r=0.70; 95%CI: 0.66,0.73; p<0.001) quantified steatosis while uncorrelated with liver stiffness (r=0.03; 95%CI: -0.04,0.11, p=0.343). Steatosis grade (Coefficient: 0.27; 95%CI: 0.07,0.47; p=0.008) was the only independent factor associated with ATI, while age, sex, BMI, chronic hepatitis, and alcohol consumption were not. ATI marginal means within S0, S1, S2, and S3 subpopulations were 0.59 (95%CI: 0.56,0.61), 0.69 (95%CI: 0.65,0.72), 0.77 (95%CI: 0.73,0.81), and 0.84 (95%CI: 0.80, 0.89) dB/cm/MHz; all contrasts between grades were significant (p<0.0001). Three ATI thresholds were calibrated to create a new ATI-based steatosis grading system (aS0 to aS3, cut-offs: 0.66, 0.73, and 0.81dB/cm/MHz). Its external validation showed Obuchowski measures (to interpret as AUC values) of 0.84±0.01 and 0.82±0.02 with histologically- and MRI-PDFF-based references.
Conclusion: ATI is a reliable non-invasive marker of steatosis. This validated ATI-based steatosis grading system could be valuable in assessing NAFLD patients.
Limitations: There is a difference in steatosis prevalence among the included studies.
Funding for this study: No funding was received for this study.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: This study was approved by the local Institutional Research Board.