Diagnostic of hepatic fibrosis with the XL probe of the Fibroscan versus biopsies in patients candidates to bariatric surgery

Guided-VCTE: An Enhanced FibroScan Examination With Improved Guidance and Applicability

OBJECTIVE

Although FibroScan (FS), based on Vibration-Controlled Transient Elastography (VCTE), is a widely used non-invasive device for assessing liver fibrosis and steatosis, its current standard-VCTE examination remains timely and difficult on patients with obesity. The Guided-VCTE examination uses continuous shear waves to locate the liver by providing a real-time predictive indicator for shear wave propagation and uses shear wave maps averaging to increase the signal-to-noise ratio in difficult to assess patients. We aimed to evaluate the effectiveness of the new indicator, as well as compare examination times and success rates with both standard-VCTE and Guided-VCTE examinations.

METHODS

We recruited 130 patients all with varying BMI in this multicenter study. Sensitivity, specificity, positive predictive values and negative predictive values assessed the new indicator effectiveness. Success rates were compared using Wilcoxon signed rank tests rates and time-to-event analyses were used to investigate examination times. Agreement and repeatability of both methods were assessed using Wilcoxon signed-rank test.

RESULTS

The new indicator was highly effective, with a 97% sensitivity for predicting valid liver stiffness measurements (LSM). LSM and controlled attenuation parameter results remained in good agreement between two examinations. The Guided-VCTE examination significantly increased the success rate of individual measurements and significantly reduced the time required for localization in the study cohort, especially in patients with grade 2 obesity (BMI ≥35 kg/m²). Additionally, the proportion of patients scanned in less than 4 minutes was significantly higher with the Guided-VCTE examination.

CONCLUSION

Guided-VCTE is a new effective technique that simplifies further FS use, particularly for patients with obesity.

Optimal cut-offs of vibration-controlled transient elastography and magnetic resonance elastography in diagnosing advanced liver fibrosis in patients with nonalcoholic fatty liver disease: A systematic review and meta-analysis

BACKGROUND/AIMS

Opinions differ regarding vibration-controlled transient elastography and magnetic resonance elastography (VCTE/MRE) cut-offs for diagnosing advanced fibrosis (AF) in patients with non-alcoholic fatty liver disease (NAFLD). We investigated the diagnostic performance and optimal cut-off values of VCTE and MRE for diagnosing AF.

METHODS

Literature databases, including Medline, EMBASE, Cochrane Library, and KoreaMed, were used to identify relevant studies published up to June 13, 2023. We selected studies evaluating VCTE and MRE regarding the degree of liver fibrosis using liver biopsy as the reference. The sensitivity, specificity, and area under receiver operating characteristics curves (AUCs) of the pooled data for VCTE and MRE for each fibrosis stage and optimal cut-offs for AF were investigated.

RESULTS

A total of 19,199 patients from 63 studies using VCTE showed diagnostic AUC of 0.83 (95% confidence interval: 0.80-0.86), 0.83 (0.80-0.86), 0.87 (0.84-0.90), and 0.94 (0.91-0.96) for ≥F1, ≥F2, ≥F3, and F4 stages, respectively. Similarly, 1,484 patients from 14 studies using MRE showed diagnostic AUC of 0.89 (0.86-0.92), 0.92 (0.89-0.94), 0.89 (0.86-0.92), and 0.94 (0.91-0.96) for ≥F1, ≥F2, ≥F3, and F4 stages, respectively. The diagnostic AUC for AF using VCTE was highest at 0.90 with a cut-off of 7.1-7.9 kPa, and that of MRE was highest at 0.94 with a cut-off of 3.62-3.8 kPa.

CONCLUSION

VCTE (7.1-7.9 kPa) and MRE (3.62-3.8 kPa) with the suggested cut-offs showed favorable accuracy for diagnosing AF in patients with NAFLD. This result will serve as a basis for clinical guidelines for non-invasive tests and differential diagnosis of AF.

A liver secretome gene signature-based approach for determining circulating biomarkers of NAFLD severity

Non-invasive biomarkers of non-alcoholic fatty liver disease (NAFLD) supporting diagnosis and monitoring disease progression are urgently needed. The present study aimed to establish a bioinformatics pipeline capable of defining and validating NAFLD biomarker candidates based on paired hepatic global gene expression and plasma bioanalysis from individuals representing different stages of histologically confirmed NAFLD (no/mild, moderate, more advanced NAFLD). Liver secretome gene signatures were generated in a patient cohort of 26 severely obese individuals with the majority having no or mild fibrosis. To this end, global gene expression changes were compared between individuals with no/mild NAFLD and moderate/advanced NAFLD with subsequent filtering for candidate gene products with liver-selective expression and secretion. Four candidate genes, including LPA (lipoprotein A), IGFBP-1 (insulin-like growth factor-binding protein 1), SERPINF2 (serpin family F member 2) and MAT1A (methionine adenosyltransferase 1A), were differentially expressed in moderate/advanced NAFLD, which was confirmed in three independent RNA sequencing datasets from large, publicly available NAFLD studies. The corresponding gene products were quantified in plasma samples but could not discriminate among different grades of NAFLD based on NAFLD activity score. Conclusion: We demonstrate a novel approach based on the liver transcriptome allowing for identification of secreted hepatic gene products as potential circulating diagnostic biomarkers of NAFLD. Using this approach in larger NAFLD patient cohorts may yield potential circulating biomarkers for NAFLD severity.

Evaluation of nonalcoholic fatty liver disease (NAFLD) in severe obesity using noninvasive tests and imaging techniques

The prevalence of nonalcoholic fatty liver disease (NAFLD) and the more severe and inflammatory type, nonalcoholic steatohepatitis (NASH), is increasing rapidly. Especially in high-risk patients, that is those with obesity, metabolic syndrome, and type 2 diabetes mellitus, the prevalence of NAFLD can be as high as 80% while NASH may be present in 20% of these subjects. With the worldwide increase of obesity, it is most likely that these numbers will rise. Since advanced stages of NAFLD and NASH are strongly associated with morbidity and mortality-in particular, cardiovascular disease, liver cirrhosis, and hepatocellular carcinoma-it is of great importance to identify subjects at risk. A great variety of noninvasive tests has been published to diagnose NAFLD and NASH, especially using blood- and imaging-based tests. Liver biopsy remains the gold standard for NAFLD/NASH. This review aims to summarize the different mechanisms leading to NASH and liver fibrosis, the different noninvasive liver tests to diagnose and evaluate patients with severe obesity.

Prospective comparison of transient elastography, MRI and serum scores for grading steatosis and detecting non-alcoholic steatohepatitis in bariatric surgery candidates

Background & Aims

Tools for the non-invasive diagnosis of non-alcoholic steatohepatitis (NASH) in morbidly obese patients with suspected non-alcoholic fatty liver disease (NAFLD) are an unmet clinical need. We prospectively compared the performance of transient elastography, MRI, and 3 serum scores for the diagnosis of NAFLD, grading of steatosis and detection of NASH in bariatric surgery candidates.

Methods

Of 186 patients screened, 152 underwent liver biopsy, which was used as a reference for NAFLD (steatosis [S]>5%), steatosis grading and NASH diagnosis. Biopsies were read by a single expert pathologist. MRI-based proton density fat fraction (MRI-PDFF) was measured in an open-bore, vertical field 1.0T scanner and controlled attenuation parameter (CAP) was measured by transient elastography, using the XL probe. Serum scores (SteatoTest, hepatic steatosis index and fatty liver index) were also calculated.

Results

The applicability of MRI was better than that of FibroScan (98% vs. 79%; p <0.0001). CAP had AUROCs of 0.83, 0.79, 0.73 and 0.69 for S>5%, S>33%, S>66% and NASH, respectively. Transient elastography had an AUROC of 0.80 for significant fibrosis (F0-F1 vs. F2-F3). MRI-PDFF had AUROCs of 0.97, 0.95, 0.92 and 0.84 for S>5%, S>33%, S>66% and NASH, respectively. When compared head-to-head in the 97 patients with all valid tests available, MRI-PDFF outperformed CAP for grading steatosis (S>33%, AUROC 0.97 vs. 0.78; p <0.0003 and S>66%, AUROC 0.93 vs. 0.75; p = 0.0015) and diagnosing NASH (AUROC 0.82 vs. 0.68; p = 0.0056). When compared in "intention to diagnose" analysis, MRI-PDFF outperformed CAP, hepatic steatosis index and fatty liver index for grading steatosis (S>5%, S>33% and S>66%).

Conclusion

MRI-PDFF outperforms CAP for diagnosing NAFLD, grading steatosis and excluding NASH in morbidly obese patients undergoing bariatric surgery.

Lay summary

Non-invasive tests for detecting fatty liver and steatohepatitis, the active form of the disease, have not been well studied in obese patients who are candidates for bariatric surgery. The most popular tests for this purpose are Fibroscan, which can be used to measure the controlled attenuation parameter (CAP), and magnetic resonance imaging, which can be used to measure the proton density fat fraction (MRI-PDFF). We found that, when taking liver biopsy as a reference, MRI-PDFF performed better than CAP for detecting and grading fatty liver as well as excluding steatohepatitis in morbidly obese patients undergoing bariatric surgery.

The Use of Transient Elastography Technology in the Bariatric Patient: a Review of the Literature

Transient elastography (TE) is a non-invasive technology that demonstrates promise in assessing liver steatosis and fibrosis without the risks of traditional percutaneous liver biopsy. Many studies have examined its reliability in respect to liver biopsy, but fewer have examined using TE in obese and bariatric surgery patients. With evidence showing that bariatric surgery can lead to improvement of liver steatosis and fibrosis, TE has the potential to provide a simple avenue of hepatic assessment in patients before and after procedures. This review article investigates what is known about the reliability of TE and its implementation in obese and bariatric surgery patients.