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 (G60-Hz ) and 80-Hz (G80-Hz ) were obtained with an MR elastogram. The difference value between G80-Hz and G60-Hz (ΔG) was calculated. Four values (G60-Hz , G80-Hz , G60-Hz - ΔG, and G80-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 G80-Hz (6.23 ± 3.67 kPa) was significantly higher than that of G60-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 G80-Hz and G80-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.

Multimaterial Decomposition Algorithm for the Quantification of Liver Fat Content by Using Fast-Kilovolt-Peak Switching Dual-Energy CT: Clinical Evaluation.

Purpose To assess the clinical accuracy and reproducibility of liver fat quantification with the multimaterial decomposition (MMD) algorithm, comparing the performance of MMD with that of magnetic resonance (MR) spectroscopy by using liver biopsy as the reference standard. Materials and Methods This prospective study was approved by the institutional ethics committee, and patients provided written informed consent. Thirty-three patients suspected of having hepatic steatosis underwent non-contrast material-enhanced and triple-phase dynamic contrast-enhanced dual-energy computed tomography (CT) (80 and 140 kVp) and single-voxel proton MR spectroscopy within 30 days before liver biopsy. Percentage fat volume fraction (FVF) images were generated by using the MMD algorithm on dual-energy CT data to measure hepatic fat content. FVFs determined by using dual-energy CT and percentage fat fractions (FFs) determined by using MR spectroscopy were compared with histologic steatosis grade (0-3, as defined by the nonalcoholic fatty liver disease activity score system) by using Jonckheere-Terpstra trend tests and were compared with each other by using Bland-Altman analysis. Real non-contrast-enhanced FVFs were compared with triple-phase contrast-enhanced FVFs to determine the reproducibility of MMD by using Bland-Altman analyses. Results Both dual-energy CT FVF and MR spectroscopy FF increased with increasing histologic steatosis grade (trend test, P < .001 for each). The Bland-Altman plot of dual-energy CT FVF and MR spectroscopy FF revealed a proportional bias, as indicated by the significant positive slope of the line regressing the difference on the average (P < .001). The 95% limits of agreement for the differences between real non-contrast-enhanced and contrast-enhanced FVFs were not greater than about 2%. Conclusion The MMD algorithm quantifying hepatic fat in dual-energy CT images is accurate and reproducible across imaging phases. © RSNA, 2017 Online supplemental material is available for this article.

Magnetic resonance elastography in the assessment of hepatic fibrosis: a study comparing transient elastography and histological data in the same patients.

PURPOSE: To evaluate the quantitative measurement of liver stiffness (LS), compare the diagnostic performance of magnetic resonance elastography (MRE) and ultrasound-based transient elastography (TE), and evaluate two different MRE-based LS measurement methods. METHODS: Between October 2013 and January 2015, 116 consecutive patients with chronic liver disease underwent MRE to measure LS (kilopascals; kPa). Of the 116 patients, 51 patients underwent both TE and liver biopsy, and the interval between the liver biopsy and both the MRE and TE was less than 90 days. MRE-derived LS values were measured on the anterior segment of the right lobe (single small round regions of interest per slice; srROIs) and whole right lobe of the liver (free hand region of interest; fhROI), and these values were correlated with pathological fibrosis grades and diagnostic performance. RESULTS: Pathological fibrosis stage was significantly correlated with srROIs (r = 0.87, p < 0.001), fhROI (r = 0.80, p < 0.001), and TE (r = 0.73, p < 0.001). For detection of significant fibrosis (≥F2), advanced fibrosis (≥F3), and cirrhosis, the area under the curve (AUC) associated with the srROIs was largest, and there was a significant difference between srROIs and TE (0.93 vs. 0.82, p = 0.006), srROIs and fhROI (0.93 vs. 0.89, p = 0.04) for detection of ≥F2. For advanced fibrosis and cirrhosis detection, AUCs were not significant (0.92-0.96). CONCLUSIONS: MRE and TE detected liver fibrosis with comparable accuracy. In particular, the srROIs method was effective for detecting of significant fibrosis.

Optimizing signal intensity correction during evaluation of hepatic parenchymal enhancement on gadoxetate disodium-enhanced MRI: comparison of three methods.

OBJECTIVE: To compare signal intensity (SI) correction using scale and rescale slopes with SI correction using SIs of spleen and muscle for quantifying multiphase hepatic contrast enhancement with Gd-EOB-DTPA by assessing their correlation with T1 values generated from Look-Locker turbo-field-echo (LL-TFE) sequence data (ER-T1). MATERIALS AND METHODS: Thirty patients underwent Gd-EOB-DTPA-enhanced magnetic resonance imaging (MRI) in this prospective clinical study. For each patient, breath-hold T1-weighted fat-suppressed three-dimensional (3D) gradient echo sequences (e-THRIVE) were acquired before and 2 (first phase), 10 (second phase), and 20min (third phase) after intravenous Gd-EOB-DTPA. Look-Locker turbo-field-echo (LL-TFE) sequences were acquired before and 1.5 (first phase), 8 (second phase), and 18min (third phase) postcontrast. The liver parenchyma enhancement ratios (ER) of each phase were calculated using the SI from e-THRIVE sequences (ER-SI) and the T1 values generated from LL-TFE sequence data (ER-T1) respectively. ER-SIs were calculated in three ways: (1) comparing with splenic SI (ER-SI-s), (2) comparing with muscle SI (ER-SI-m), (3) using scale and rescale slopes obtained from DICOM headers (ER-SI-c), to eliminate the effects of receiver gain and scaling. For each of the first, second and third phases, correlation and agreement were assessed between each ER-SI and ER-T1. RESULTS: In the first phase, all ER-SIs correlated weakly with ER-T1. In the second and third phases, ER-SI-c showed a stronger linear correlation with ER-T1 (r(2)=0.71-0.72, p<0.01) than did ER-SI-s (r(2)=0.37-0.39, p<0.01) or ER-SI-m (r(2)=0.30-0.41, p<0.01). CONCLUSION: SI correction using scale and rescale slopes from DICOM data is the most acceptable algorithm for evaluating delayed-phase Gd-EOB-DTPA hepatic enhancement.

Comparison between T1 relaxation time of Gd-EOB-DTPA-enhanced MRI and liver stiffness measurement of ultrasound elastography in the evaluation of cirrhotic liver.

PURPOSE: To compare four imaging approaches in cirrhotic estimation; pre-enhancement T1 relaxation time (T1RT), reduction rate (RR) of T1RT, signal-based liver-to-muscle ratio (L/M ratio) on gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI), and liver stiffness measurement (LSM) of US elastography. MATERIALS AND METHODS: Consecutive 58 patients with chronic liver diseases who underwent both Gd-EOB-DTPA-enhanced MRI and FibroScan were analyzed. Four imaging approaches were evaluated by fibrosis score from liver biopsy and receiver operating characteristic (ROC) analysis. RESULTS: RR was found to be inversely correlated with LSM (r = -0.65). RR decreased with degree of fibrosis (F0-F1, 58.5 ± 6.2%, versus F2-F3-F4, 48.8 ± 11.7%, P = 0.010, F0-F1-F2, 58.2 ± 6.2% versus F3-F4, 45.5 ± 12.3%, P = 0.010 and F0-F1, 58.5 ± 6.2%, versus F2-F3, 52.1 ± 12.0%, P = 0.0038). LSM increased with degree of fibrosis (F0-F1, 5.4 ± 2.2 kPa versus F2-F3-F3, 19.3 ± 15.5 kPa, P = 0.0011 and F0-F1-F2, 6.8 ± 3.6 kPa versus F3-F4, 23.8 ± 17.1 kPa, P = 0.0029 and F0-F1, 5.4 ± 2.2 kPa, versus F2-F3, 11.4 ± 7.2 kPa, P = 0.0098). Area under ROC curves were 0.83 (F3-F4), 0.72 (F2-F3-F4), 0.68 (F2-F3) for RR and 0.83 (F3-F4), 0.88 (F2-F3-F4), 0.81 (F2-F3) for LSM in discriminating between patients with fibrosis. CONCLUSION: The capability by LSM was better than those by RR of T1RT, pre-enhancement T1RT, and L/M ratio to differentiate F ≥ 2, but LSM and RR of T1RT showed the same value to differentiate F ≥ 3.