Dual‐frequency MR elastography to differentiate between inflammation and fibrosis of the liver: Comparison with histopathology

Background Differentiation between inflammation and fibrosis is an important clinical distinction in patients with chronic liver disease, which has been difficult so far with MR elastography. Purpose To investigate whether dual‐frequency MR elastography can estimate necroinflammation of the liver and improve diagnostic performance for the staging of liver fibrosis. Study Type Retrospective. Subjects In all, 30 patients (14 males, 16 females) with chronic liver disease. Field Strength/Sequence 1.5T/dual‐frequency MR elastography at 60‐Hz and 80‐Hz vibration frequencies. [Correction added on November 12, 2019, after first online publication: The field strength in the preceding sentence was corrected.] Assessment Necroinflammation activity and fibrosis were assessed using the METAVIR scoring system. Stiffness values at 60‐Hz (G 60‐Hz ) and 80‐Hz (G 80‐Hz ) were obtained with an MR elastogram. The difference value between G 80‐Hz and G 60‐Hz (ΔG) was calculated. Four values (G 60‐Hz , G 80‐Hz , G 60‐Hz – ΔG, and G 80‐Hz + ΔG) were generated to estimate necroinflammation and fibrosis. Statistical Tests The ΔG were correlated with necroinflammation activity grade and fibrosis stage using Spearman's rank correlation. Diagnostic performance of the four values for necroinflammation activity grade and fibrous stage was assessed by using area under the receiver operating characteristic curve (AUC). Results The mean value of G 80‐Hz (6.23 ± 3.67 kPa) was significantly higher than that of G 60‐Hz (5.27 ± 3.14 kPa) ( P < 0.0001). The ΔG demonstrated a strong correlation with necroinflammation grade (ρ = 0.625, P < 0.001) and no correlation with fibrosis stage (ρ = 0.306, P = 0.113). The AUC of the G 80‐Hz and G 80‐Hz + ΔG showed higher accuracy for necroinflammation, and optimal cutoff values yielded better discrimination of ≥A1, ≥A2, and = A3. The AUC demonstrated that all the generated values had high diagnostic performance (≥0.87 for all) for fibrosis. Data Conclusion Dual‐frequency MR elastography shows potential in estimating necroinflammation of the liver and may improve diagnostic performance for staging liver fibrosis. Level of Evidence: 3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2020;51:1053–1064.