Magnetic resonance elastography is as accurate as liver biopsy for liver fibrosis staging

BackgroundLiver MR elastography (MRE) is available for the noninvasive assessment of liver fibrosis; however, no previous studies have compared the diagnostic ability of MRE with that of liver biopsy. PurposeTo compare the diagnostic accuracy of liver fibrosis staging between MRE-based methods and liver biopsy using the resected liver specimens as the reference standard. Study TypeA retrospective study at a single institution. PopulationIn all, 200 patients who underwent preoperative MRE and subsequent surgical liver resection were included in this study. Data from 80 patients were used to estimate cutoff and distributions of liver stiffness values measured by MRE for each liver fibrosis stage (F0-F4, METAVIR system). In the remaining 120 patients, liver biopsy specimens were obtained from the resected liver tissues using a standard biopsy needle. Field Strength/Sequence2D liver MRE with gradient-echo based sequence on a 1.5 or 3T scanner was used. AssessmentTwo radiologists independently measured the liver stiffness value on MRE and two types of MRE-based methods (threshold and Bayesian prediction method) were applied. Two pathologists evaluated all biopsy samples independently to stage liver fibrosis. Surgically resected whole tissue specimens were used as the reference standard. Statistical TestsThe accuracy for liver fibrosis staging was compared between liver biopsy and MRE-based methods with a modified McNemar's test. ResultsAccurate fibrosis staging was achieved in 53.3% (64/120) and 59.1% (71/120) of patients using MRE with threshold and Bayesian methods, respectively, and in 51.6% (62/120) with liver biopsy. Accuracies of MRE-based methods for diagnoses of F2 (90-91% [108-9/120]), F3 (79-81% [95-97/120]), and F4 (82-85% [98-102/120]) were statistically equivalent to those of liver biopsy (F2, 79% [95/120], P 0.01; F3, 88% [105/120], P 0.006; and F4, 82% [99/120], P 0.017). Data ConclusionMRE can be an alternative to liver biopsy for fibrosis staging. Level of Evidence: 3. Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;47:1268-1275.