Validation of the FibroScan-aspartate aminotransferase score by vibration-controlled transient and B-mode ultrasound elastography

FibroScan-AST score for diagnosing fibrotic MASH: A systematic review and meta-analysis of diagnostic test accuracy studies

BACKGROUND AND AIM

Following the approval of the first agent for the management of metabolic dysfunction-associated steatohepatitis (MASH), identification of patients with fibrotic MASH (MASH with NAS ≥ 4 and fibrosis stage ≥ 2) is crucial. We assessed the performance of FibroScan-aspartate aminotransferase (AST) score (FAST) for ruling in/out fibrotic MASH.

METHODS

We searched Medline, Cochrane Library, Web of Science, Scopus, and gray literature sources up to January 11, 2024. Studies were eligible if they assessed the accuracy of FAST score for the detection of fibrotic MASH using biopsy as the reference standard at previously reported thresholds (FAST ≥ 0.67 for ruling-in and ≤ 0.35 for ruling-out fibrotic MASH). We calculated pooled sensitivity and specificity estimates for FAST thresholds alongside 95% confidence intervals following bivariate random- effects models. We assessed the certainty of evidence using the Grading of Recommendations Assessment, Development and Evaluation framework.

RESULTS

We included 16 studies with 8838 participants. A FAST score ≥ 0.67 yielded a pooled specificity of 0.87 (0.82-0.90) while a FAST score ≤ 0.35 yielded a summary sensitivity of 0.88 (0.83-0.91). At a prevalence of 30%, the positive predictive value for ruling-in fibrotic MASH was 60% while the negative predictive value for ruling-out the target condition was 91%. AST levels, cirrhosis prevalence, and number of pathologists reviewing biopsies were sources of heterogeneity among studies. The certainty of evidence was low to very low.

CONCLUSIONS

FAST score can be used as a triage test for ruling out fibrotic MASH. Nevertheless, its low positive predictive value necessitates sequential testing for ruling-in fibrotic MASH.

Ultrasonographic Assessment of Tissue Stiffness: Recent Progress in Transient Elastography and Shear Wave Elastography in the Liver and Various Organs

Ultrasonography is a noninvasive and widely accessible modality in clinical practice. Recently, ultrasonography has been used to evaluate tissue stiffness; the two representative techniques are transient elastography (FibroScan®) and shear wave elastography. These modalities are now generally used for the assessment of liver fibrosis, the prediction of hepatocarcinogenesis, and determining prognosis. In addition, shear wave elastography is available, not only for the liver but also for various other organs, including the breast and brain. In the breast and brain, shear wave elastography distinguishes malignant lesions from benign ones. Moreover, shear wave elastography can be useful for differentiating between ischemic and hemorrhagic strokes. This review summarizes the recent progress in transient elastography and shear wave elastography of the liver and introduces the advantages of ultrasonographic assessment of tissue stiffness in various organs, including the breast, brain, kidney, heart, thyroid, pancreas, muscle, and bone.

B-mode shear wave elastography can be an alternative method to vibration-controlled transient elastography according to a moderate-scale population study

PURPOSE

We aimed to compare vibration-controlled transient elastography (VCTE) with shear wave elastography (SWE) without previous analysis and generate regression equations between VCTE and new point SWE using combination-elastography.

METHODS

Overall, 829 patients with chronic liver disease were enrolled in this study. Patients with a skin-liver capsule distance > 25 mm were excluded. The reproducibility of VCTE and SWE was confirmed in a phantom study and a clinical study. Considering that combination-elastography allows measurement based on strain elastography, a similar analysis was performed for the liver fibrosis index (LFI), which is a quantitative value for evaluation of liver fibrosis calculated using strain elastography image features. Regression equations between the VCTE and SWE values were obtained based on linear regression analysis.

RESULTS

In the phantom study and clinical study, there was a strong correlation between VCTE and SWE [r = 0.995 (p < 0.001) and r = 0.747 (p < 0.001), respectively). The regression equation between VCTE and SWE was VCTE (kPa) = 1.09 × point SWE (kPa) - 0.17. The Bland-Altman plots revealed no statistically significant bias. Meanwhile, there was no correlation between VCTE and LFI (r = 0.279). There was a statistically significant bias between VCTE and LFI in the Bland-Altman plots. The inter-operator reliability showed a good intraclass correlation coefficient of 0.760 (95% confidence interval: 0.720-0.779).

CONCLUSION

Liver stiffness measured using point SWE was comparable to that measured using VCTE.

Roles of Radiological Tests in Clinical Trials and the Clinical Management of Nonalcoholic Fatty Liver Disease

Radiological testing is now routinely used for clinical trial prescreening, diagnosis, and treatment and referral. The CAP performs well in detecting fatty liver but is unable to grade and track longitudinal changes. MRI-PDFF is a better technique for evaluating longitudinal changes and is used as a primary endpoint in trials of antisteatotic agents. The probability of detecting liver fibrosis using radiological testing techniques is high when performed at referral centers, and reasonable imaging strategies include the combination of FIB-4 and VCTE, the FAST Score, MAST, and MEFIB. The strategy currently recommended is the sequential application of FIB-4 and VCTE.

Diagnostic accuracy of FibroScan-AST (FAST) score for the non-invasive identification of patients with fibrotic non-alcoholic steatohepatitis: a systematic review and meta-analysis

OBJECTIVE

A simple combined score with liver stiffness, controlled attenuation parameter and serum aspartate aminotransferase (AST), the FibroScan-AST (FAST) score, has been proposed to non-invasively identify patients with fibrotic non-alcoholic steatohepatitis (NASH). We performed a systematic review and meta-analysis of published studies to evaluate the overall diagnostic accuracy of the FAST score in identifying patients with fibrotic NASH.

DESIGN

We systematically searched MEDLINE, Ovid Embase, Scopus and Cochrane Library electronic databases for full-text published articles in any language between 3 February 2020 and 30 April 2022. We included original articles that reported data for the calculation of sensitivity and specificity of the FAST score for identifying adult patients with fibrotic NASH adults, according to previously described rule-out (≤0.35) and rule-in (≥0.67) cut-offs.

RESULTS

We included 12 observational studies for a total of 5835 participants with biopsy-confirmed non-alcoholic fatty liver disease. The pooled prevalence of fibrotic NASH was 28% (95% CI 21% to 34%). The FAST score's pooled sensitivity was 89% (95% CI 82% to 93%), and the pooled specificity was 89% (95% CI 83% to 94%) according to the aforementioned rule-in/rule-out cut-offs. The negative predictive value and positive predictive value of the FAST score were 92% (95% CI 91% to 95%) and 65% (95% CI 53% to 68%), respectively. Subgroup analyses and influential bias analyses did not alter these findings.

CONCLUSION

The results of our meta-analysis show that the FAST score has a good performance for non-invasive diagnosis of fibrotic NASH. Therefore, this score can be used to efficiently identify patients who should be referred for a conclusive liver biopsy and/or consideration for treatment with emerging pharmacotherapies.

PROSPERO REGISTRATION NUMBER

CRD42022350945.