NON-ALCOHOLIC FATTY LIVER DISEASE: MODERN DIAGNOSTIC APPROACHES – INVASIVE AND NON-INVASIVE METHODS

Abstract

Non-alcoholic fatty liver disease (NAFLD), now increasingly referred to as metabolic dysfunction-associated steatotic liver disease (MASLD), represents a global public health challenge with a growing prevalence paralleling the obesity and type 2 diabetes mellitus epidemics. The disease spectrum ranges from simple steatosis to non-alcoholic steatohepatitis (NASH), which can progress to cirrhosis and hepatocellular carcinoma. Accurate diagnosis and risk stratification are critical for guiding management and predicting outcomes. Historically, liver biopsy has been the gold standard for diagnosing NASH and staging fibrosis. However, its invasiveness, sampling variability, and associated risks necessitate the development and validation of reliable non-invasive alternatives. This review synthesizes contemporary literature on the diagnostic landscape of NAFLD, comparing the utility, accuracy, and limitations of invasive histopathological assessment with a spectrum of non-invasive tools. These tools include biochemical scores (e.g., FIB-4, NFS), quantitative imaging techniques (vibration-controlled transient elastography, magnetic resonance elastography, and proton density fat fraction), and emerging biomarkers. The evidence underscores a paradigm shift towards a stepwise, risk-stratification approach where non-invasive methods serve as primary screening and diagnostic tools, reserving liver biopsy for ambiguous cases or when concomitant liver diseases are suspected. This article critically evaluates these modalities, offering a framework for clinicians to navigate the evolving diagnostic algorithm.