Comparative Precision of 3D MRE and 2D MRE for Measurement of Liver Stiffness in Adults with Severe Obesity.

Abstract

Background The comparative precision of two-dimensional (2D) MR elastography (MRE) and three-dimensional (3D) MRE for measuring liver stiffness (LS) in adults with severe obesity is unknown. Purpose To compare test-retest repeatability, between-day reproducibility, and between-field-strength reproducibility of 2D MRE- and 3D MRE-based LS measurements in adults with severe obesity. Materials and Methods In this prospective dual-center study (December 2020 to August 2023), adults with severe obesity underwent 2D MRE and 3D MRE at one visit before weight loss surgery and two visits after. At each visit, MRE was repeated with interexamination repositioning at 3 T to assess test-retest repeatability, or at 1.5 T and 3 T to assess between-field-strength reproducibility. Some participants also underwent MRE 1-3 days before visit 1 to assess between-day reproducibility at 1.5 T or 3 T. All participant visits were performed at the same site. Absolute repeatability coefficient (RC) and proportional RC (RC%), absolute reproducibility coefficient (RDC) and proportional RDC (RDC%), intraclass correlation coefficient (ICC), and technical failure rates were computed for 2D MRE-based and 3D MRE-based LS and compared pairwise (bootstrap-based tests or McNemar test of paired proportions for clustered data, as appropriate). Results In a total of 103 participants (mean age, 44 years ± 10.0; 89 women), LS ranges were 2.2 kPa ± 0.4 with 2D MRE and 2.0 kPa ± 0.3 with 3D MRE. At 3 T, 3D MRE had better test-retest repeatability than did 2D MRE (RC, 0.26 vs 0.55 kPa, respectively; RC%, 12.6% vs 19.9%; ICC, 0.85 vs 0.67; all <i>P</i> < .001). Three-dimensional MRE had better between-field-strength reproducibility than did 2D MRE (RDC, 0.26 vs 0.38 kPa, respectively; RDC%, 14.6% vs 18.5%; both <i>P</i> < .001). Three-dimensional MRE had better between-day reproducibility than did 2D MRE at 3 T (RDC, 0.22 vs 0.48 kPa, respectively; <i>P</i> = .007), but not at 1.5 T. However, 3D MRE had a higher failure rate than did 2D MRE (4.9% [29 of 587] vs 2.9% [17 of 583]; <i>P</i> = .007). Conclusion Compared with 2D MRE, 3D MRE had better precision for measuring liver stiffness in adults with severe obesity but failed more frequently. ClinicalTrials.gov identifier: NCT03674528 © The Author(s) 2026. Published by the Radiological Society of North America under a CC BY 4.0 license. <i>Supplemental material is available for this article.</i> See also the editorial by Hu in this issue.