Magnetic resonance elastography is accurate in detecting advanced fibrosis in autoimmune hepatitis

AIM To assess the value of magnetic resonance elastography (MRE) in detecting advanced fibrosis/cirrhosis in autoimmune hepatitis (AIH). METHODS In this retrospective study, 36 patients (19 treated and 17 untreated) with histologically confirmed AIH and liver biopsy performed within 3 mo of MRE were identified at a tertiary care referral center. Liver stiffness (LS) with MRE was calculated by a radiologist, and inflammation grade and fibrosis stage in liver biopsy was assessed by a pathologist in a blinded fashion. Two radiologists evaluated morphological features of cirrhosis on conventional magnetic resonance imaging (MRI). Accuracy of MRE was compared to laboratory markers and MRI for detection of advanced fibrosis/cirrhosis. RESULTS Liver fibrosis stages of 0, 1, 2, 3 and 4 were present in 4, 6, 7, 6 and 13 patients respectively. There were no significant differences in distribution of fibrosis stage and inflammation grade between treated and untreated patient groups. LS with MRE demonstrated stronger correlation with liver fibrosis stage in comparison to laboratory markers for chronic liver disease (r = 0.88 vs -0.48-0.70). A trend of decreased mean LS in treated patients compared to untreated patients was observed (3.7 kPa vs 3.84 kPa) but was not statistically significant. MRE had an accuracy/sensitivity/specificity/positive predictive value/negative predictive value of 0.97/90%/100%/100%/90% and 0.98/92.3%/96%/92.3%/96% for detection of advanced fibrosis and cirrhosis, respectively. The performance of MRE was significantly better than laboratory tests for detection of advanced fibrosis (0.97 vs 0.53-0.80, p < 0.01), and cirrhosis (0.98 vs 0.58-0.80, p < 0.01) and better than conventional MRI for diagnosis of cirrhosis (0.98 vs 0.78, p = 0.002). CONCLUSION MRE is a promising modality for detection of advanced fibrosis and cirrhosis in patients with AIH with superior diagnostic accuracy compared to laboratory assessment and MRI.

Three-Tesla magnetic resonance elastography for hepatic fibrosis:Comparison with diffusion-weighted imaging and gadoxetic acid-enhanced magnetic resonance imaging

AIM: To evaluate the feasibility of 3-Tesla magnetic resonance elastography (MRE) for hepatic fibrosis and to compare that with diffusion-weighted imaging (DWI) and gadoxetic acid-enhanced magnetic resonance (MR) imaging.

Skeletal muscle stiffness as measured by magnetic resonance elastography after chronic spinal cord injury:a cross-sectional pilot study

Skeletal muscle stiffness is altered after spinal cord injury(SCI).Assessing muscle stiffness is essential for rehabilitation and pharmaceutical interventions design after SCI.The study used magnetic resonance elastography to assess the changes in stiffness after chronic SCI compared to matched able-bodied controls and determine its association with muscle size,spasticity,and peak torque in persons with SCI.Previous studies examined the association between muscle stiffness and spasticity,however,we are unaware of other studies that examined the effects of muscle composition on stiffness after SCI.Ten participants(one female)with chronic SCI and eight(one female)matched able-bodied controls participated in this cross-sectional study.Magnetic resonance elastography was utilized to monitor stiffness derived from shear waves propagation.Modified Ashworth scale was used to evaluate spasticity scores in a blinded fashion.Peak isometric and isokinetic torques were measured using a biodex dynamometer.Stiffness values were non-significantly lower(12.5%;P=0.3)in the SCI group compared to able-bodied controls.Moreover,stiffness was positively related to vastus lateralis whole muscle cross-sectional area(CSA)(r2=0.64,P<0.005)and vastus lateralis absolute muscle CSA after accounting for intramuscular fat(r2=0.78,P<0.0007).Stiffness was also positively correlated to both isometric(r2=0.55-0.57,P<0.05)and isokinetic peak(r2=0.46-0.48,P<0.05)torques.Our results suggest that larger clinical trial is warranted to confirm the preliminary findings that muscle stiffness is altered after SCI compared to healthy controls.Stiffness appeared to be influenced by infiltration of intramuscular fat and modestly by the spasticity of the paralyzed muscles.The preliminary data indicated that the relationship between muscle stiffness and peak torque is not altered with changing the frequency of pulses or angular velocities.All study procedures were approved by the Institutional Review Board at the Hunter Holmes McGuire VA Medical Center,USA(IRB#:02314)on May 3,2017.

Comparison of Magnetic Resonance Elastography and Diffusion-weighted Imaging for Staging Hepatic Fibrosis

Background：To compare the diagnostic values of magnetic resonance elastography （MRE） and diffusion-weighted imaging （DWI） in staging hepatic fibrosis （HF） in an animal model.Methods：This study consisted of 44 rabbits served as HF group and 9 normal rabbits.HF group was divided into two subgroups：Group A （n =32） and Group B （n =12）.Rabbits in Group B were served as a complementary group when rabbits in Group A suddenly died during the study.Rabbits from control and Group A underwent abdominal MR imaging （MRI）,MRE,and DWI.In Group A,random eight rabbits underwent MRI examinations at 4,5,6,l0 weeks after carbon tetrachloride oil subcutaneous injection.Liver stiffness （LS） and apparent diffusion coefficient （ADC） values of liver parenchyma were measured.The diagnostic performance of MRE and DWI for staging HF was compared using the receiver operating characteristic curve analysis on the basis of the histopathological analysis of HF.Results：Significant differences of LS and DWI values were present among HF stages （P 〈 0.005）.The LS values measured on MRE （r =0.838,P 〈 0.001） were more strongly correlated with the HF stages than with ADC values （r =-0.527,P 〈 0.001）.The area under the receiver operating characteristic curve values of LS were significantly larger than those of DWI were for discriminating two stages of HF （0.979 vs.0.712 for ≥ S 1,0.922 vs.0.699 for ≥ S2）.MRE showed higher specificity for predicting all stages of HF compared to DWI.Conclusions：MRE more strongly correlated with the HF stages than DWI and is more specific in predicting all HF stages.

Comparative analysis of indentation and magnetic resonance elastography for measuring viscoelastic properties

Measurement the viscoelastic properties is important for studying the developmental and pathological behavior of soft biological tissues.Magnetic resonance elastography(MRE)is a non-invasive method for in vivo measurement of tissue viscoelasticity.As a flexible method capable of testing small samples,indentation has been widely used for characterizing soft tissues.Using 2nd-order Prony series and dimensional analysis,we analyzed and compared the model parameters estimated from both indentation and MRE.Conversions of the model parameters estimated from the two methods were established.We found that the indention test is better at capturing the dynamic response of tissues at a frequency less than 10 Hz,while MRE is better for describing the frequency responses at a relatively higher range.The results provided helpful information for testing soft tissues using indentation and MRE.The models analyzed are also helpful for quantifying the frequency response of viscoelastic tissues.

Recent developments in non-invasive methods for assessing metabolic dysfunction-associated fatty liver disease

The prevalence of metabolic dysfunction-associated fatty liver disease(MAFLD)is increasing,affecting over one-third of the global population and contributing to significant morbidity and mortality.Diagnosing MAFLD,especially with advan-ced fibrosis,remains challenging due to the limitations of liver biopsy,the current gold standard.Non-invasive tests are crucial for early detection and management.Among these,the fibrosis-4 index(Fib-4)is widely recommended as a first-line test for screening for liver fibrosis.Advanced imaging techniques,including ultrasound-based elastography and magnetic resonance elastography,offer high accuracy but are limited by cost and availability.Combining biomarkers,such as in the enhanced liver fibrosis score and FibroScan-AST score,enhances diagnostic precision and is recommended to further stratify patients who are considered to be intermediate or high risk from the Fib-4 score.We believe that the future lies in the combined use of biomarkers to improve diagnostic accuracy.

Progressive changes in platelet counts and Fib-4 scores precede the diagnosis of advanced fibrosis in NASH patients

BACKGROUND Cirrhosis and its complications develop in a subgroup of patients with nonalcoholic fatty liver disease(NASH).Early detection of liver fibrosis represents an important goal of clinical care.AIM To test the hypothesis that the development of cirrhosis in nonalcoholic fatty liver disease patients is preceded by the long-term trends of platelet counts and Fib-4 scores.METHODS We identified all patients in our healthcare system who had undergone fibrosis staging by liver biopsy or magnetic resonance elastography(MRE)for nonalcoholic fatty liver disease during the past decade(n=310).Platelet counts,serum glutamic-pyruvic transaminase and serum glutamic oxalacetic transaminase values preceding the staging tests were extracted from the electronic medical record system,and Fib-4 scores were calculated.Potential predictors of advanced fibrosis were evaluated using multivariate regression analysis.RESULTS Significant decreases in platelet counts and increases in Fib-4 scores were observed in all fibrosis stages,particularly in patients with cirrhosis.In the liver biopsy group,the presence of cirrhosis was best predicted by the combination of the Fib-4 score at the time closest to staging(P<0.0001),the presence of diabetes(P=0.0001),and the correlation coefficient of the preceding timedependent drop in platelet count(P=0.044).In the MRE group,Fib4 score(P=0.0025)and platelet drop(P=0.0373)were significant predictors.In comparison,the time-dependent rise of the Fib-4 score did not contribute in a statistically significant way.CONCLUSION Time-dependent changes in platelet counts and Fib-4 scores contribute to the prediction of cirrhosis in NASH patients with biopsy-or MRE-staged fibrosis.Their incorporation into predictive algorithms may assist in the earlier identification of high-risk patients.

Non-invasive diagnosis of hepatitis B virus-related cirrhosis

Chronic hepatitis B(CHB)infection is a major public health problem associated with significant morbidity and mortality worldwide.Twenty-three percent of patients with CHB progress naturally to liver cirrhosis,which was earlier thought to be irreversible.However,it is now known that cirrhosis can in fact be reversed by treatment with oral anti-nucleotide drugs.Thus,early and accurate diagnosis of cirrhosis is important to allow an appropriate treatment strategy to be chosen and to predict the prognosis of patients with CHB.Liver biopsy is the reference standard for assessment of liver fibrosis.However,the method is invasive,and is associated with pain and complications that can be fatal.In addition,intra-and inter-observer variability compromises the accuracy of liver biopsy data.Only small tissue samples are obtained and fibrosis is heterogeneous in such samples.This confounds the two types of observer variability mentioned above.Such limitations have encouraged development of non-invasive methods for assessment of fibrosis.These include measurements of serum biomarkers of fibrosis;and assessment of liver stiffness via transient elastography,acoustic radiation force impulse imaging,real-time elastography,or magnetic resonance elastography.Although significant advances have been made,most work to date has addressed the diagnostic utility of these techniques in the context of cirrhosis caused by chronic hepatitis C infection.In the present review,we examine the advantages afforded by use of non-invasive methods to diagnose cirrhosis in patients with CHB infections and the utility of such methods in clinical practice.

Noninvasive diagnosis of cirrhosis:A review of different imaging modalities

Progressive hepatic fibrosis can lead to cirrhosis,so its early detection is fundamental.Staging fibrosis is also critical for prognosis and management.The gold standard for these aims is liver biopsy,but it has several drawbacks,as it is invasive,expensive,has poor acceptance,is prone to inter observer variability and sampling errors,has poor repeatability,and has a risk of complications and mortality.Therefore,non-invasive imaging tests have been developed.This review mainly focuses on the role of transient elastography,acoustic radiation force impulse imaging,and magnetic resonance-based methods for the noninvasive diagnosis of cirrhosis.

Noninvasive Fibrosis Assessment in Chronic Hepatitis C Infection: An Update

Liver biopsy is historically the gold standard for liver fibrosis assessment of chronic hepatitis C patients.However,with the introduction and validation of noninvasive tests(NITs)to evaluate advanced fibrosis,and the direct-acting antiviral agents for treatment of chronic hepatitis C virus(HCV),the role of NITs have become even more complex.There is now need for longitudinal monitoring and elucidation of cutoff values for prediction of liver-related complication after sustained virological response.The aim of this report is to provide a critical overview of the various NITs available for the assessment of liver fibrosis in HCV patients.