Abstract
BACKGROUND: Virtual MR elastography (VMRE) and MRE have been proposed for liver fibrosis staging in metabolic dysfunction-associated steatotic liver disease (MASLD), but VMRE's diagnostic performance remains debated. PURPOSE: To assess the inter-visit and inter-reader reproducibility of fat-uncorrected and fat-corrected diffusion-weighted imaging (DWI)-based VMRE and to compare their diagnostic performance with MRE for liver fibrosis staging in the MASLD population. STUDY TYPE: Prospective. POPULATION: Fifty four participants were enrolled: 43 with biopsy-proven MASLD (age: 57.0 ± 9.0 years; 26 males) and 11 healthy volunteers (age: 31.0 ± 15.0 years; 4 males). FIELD STRENGTH/SEQUENCE: 3.0T, DWI (b-values of 0, 200, and 1500 s/mm(2)) for VMRE and phase-contrast MRE at 60 Hz was performed. ASSESSMENT: VMRE-derived shifted apparent diffusion coefficients (sADC) reproducibility and diagnostic performance; MRE-derived stiffness diagnostic performance. STATISTICAL TESTS: Reproducibility was evaluated using intraclass correlation coefficients (ICC), within-subject coefficient of variation (wCV), and bias and limits of agreement (LOA) in Bland-Altman analysis. Diagnostic performance was assessed with areas under the receiver operating characteristic curve (AUC) and compared with DeLong's test. p < 0.05 was considered statistically significant. RESULTS: For inter-visit agreement, the ICC of fat-uncorrected and fat-corrected sADC were 0.88 and 0.83; wCV were 0.120 ± 0.30 and 0.141 ± 0.31; bias and 95% LOA were (-0.03 ± 0.18) × 10(-3) mm(2)/s and (-0.05 ± 0.33) × 10(-3) mm(2)/s, respectively. For inter-reader agreement, the ICC of fat-uncorrected and fat-corrected VMRE were 0.99 and 0.99; wCV were 0.028 ± 0.011 and 0.039 ± 0.012, respectively; bias and 95% LOA were (-0.01 ± 0.03) × 10(-3) mm(2)/s and (-0.02 ± 0.05) × 10(-3) mm(2)/s, respectively. AUC of fat-uncorrected, fat-corrected sADC, and MRE-derived stiffness for distinguishing fibrosis stages F0 versus ≥ F1 were 0.70 ± 0.17, 0.56 ± 0.18, and 0.87 ± 0.10; ≤ F1 versus ≥ F2 were 0.61 ± 0.16, 0.49 ± 0.17, and 0.86 ± 0.10; ≤ F2 versus ≥ F3 were 0.54 ± 0.16, 0.50 ± 0.16, and 0.89 ± 0.09; and ≤ F3 versus F4 were 0.58 ± 0.16, 0.55 ± 0.17, and 0.85 ± 0.11, respectively. MRE had significantly higher diagnostic performance than fat-uncorrected and fat-corrected VMRE for all fibrosis stages. DATA CONCLUSION: VMRE has good reproducibility, but has lower fibrosis staging accuracy than MRE. EVIDENCE LEVEL: 1. TECHNICAL EFFICACY: Stage 2.