Elastography by Ultrasound and Magnetic Resonance in the Assessment of Nonalcoholic Fatty Liver Disease (Nafld) Progression

Introduction: Nonalcoholic fatty liver disease (NAFLD) has become the most prevalent chronic liver disorder worldwide, with significant risk of progression to advanced fibrosis and cirrhosis. The limitations of liver biopsy have accelerated the adoption of noninvasive imaging biomarkers, particularly elastography by ultrasound and magnetic resonance, for diagnosis, staging, and longitudinal monitoring. These techniques offer reproducible quantification of liver stiffness, reflecting fibrotic burden and prognosis. Objective: The aim of this review is to critically evaluate the role of ultrasound and magnetic resonance elastography in the assessment of NAFLD progression. Secondary objectives include the analysis of technical principles, diagnostic accuracy, prognostic implications, confounding factors, and the integration of elastography into multiparametric imaging strategies. Methods: A comprehensive narrative review was conducted through PubMed, Scopus, Web of Science, Cochrane Library, and Google Scholar, including studies published from 2019 to 2024. Eligible publications comprised randomized trials, observational cohorts, systematic reviews, and consensus statements focused on elastography in NAFLD. Data were synthesized thematically to address diagnostic performance, histopathological correlation, prognostic significance, and clinical applications. Results and Discussion: Ultrasound elastography, particularly shear wave methods, provides accessible and real-time assessment of liver stiffness, though its accuracy is limited in obese patients and in the presence of ascites. Magnetic resonance elastography demonstrates superior diagnostic performance and reproducibility, correlating strongly with histological fibrosis stages and long-term outcomes. Both modalities are affected by confounders such as inflammation and congestion, requiring integration with laboratory and clinical data. Elastography has proven value in prognostication, therapeutic monitoring, and risk stratification, and is increasingly incorporated as a surrogate endpoint in clinical trials. The integration of elastography with multiparametric MRI protocols enhances comprehensive evaluation of hepatic structure and function. Conclusion: Elastography by ultrasound and magnetic resonance has redefined noninvasive assessment of NAFLD, enabling precise fibrosis staging, longitudinal monitoring, and prognostic evaluation. Its clinical relevance is supported by guideline incorporation and its growing role in clinical trials. Future directions include standardization of cut-offs, refinement of multiparametric imaging, and the application of artificial intelligence to optimize interpretation. Elastography represents a cornerstone of precision hepatology and will continue to expand its role in research and clinical practice. Descriptors: Elastography, Ultrasonography, Magnetic Resonance Imaging, Non-alcoholic Fatty Liver Disease