Retrospective comparison of liver chemical shift-encoded PDFF sampling strategies in children and adolescents.

INTRODUCTION

Multiple region-of-interest (ROI) sampling strategies have been described for liver fat quantification by MRI PDFF. While adult studies have shown that sampling strategies including as few as four ROIs provide a reasonable tradeoff between laboriousness and quantitative performance, there is a paucity of similar data for pediatric patients.

PURPOSE

To assess agreement between different ROI sampling strategies for liver MRI PDFF analysis in children and adolescents.

MATERIALS AND METHODS

This retrospective, internal review board-approved study included clinical MRI PDFF acquisitions for 50 children and adolescents. Four different ROI sampling paradigms reported in the literature were reproduced to measure mean liver PDFF. An 18-ROI (2 in each Couinaud segment) paradigm was considered the reference standard. Spearman correlation, intraclass correlation coefficients (ICCs), and Bland-Altman analyses were used to quantify agreement.

RESULTS

Mean age for the 50 participants was 14 ± 2.5 years (range 8-17 years). Based on the 18-ROI paradigm, mean PDFF was significantly higher for the right lobe (24.0 ± 13.7% right, 22.0 ± 13.1% left; p = 0.001). PDFF values for each individual Couinaud segment were highly correlated with the reference standard (ρ = 0.977 to 0.993, p < 0.0001). PDFF values derived from all sampling paradigms, including strategies using large free-hand ROIs, were strongly correlated with the reference standard (ρ = 0.995 to 0.998, p < 0.0001) with excellent agreement (ICC range 0.995 to 0.998).

CONCLUSION

Liver PDFF sampling paradigms using large ROIs showed strong correlation, excellent agreement, and nonsignificant mean differences from a reference standard paradigm sampling every Couinaud segment in children. Paradigms that exclusively sample the right lobe may overestimate liver PDFF.