Diagnostic Utility of Ultrasound in Identifying Fatty Liver Disease Among Non-Obese Individuals- A Prospective Observational Study

Diagnostic Utility of Ultrasound in Identifying Fatty Liver Disease Among Non-Obese Individuals

Abstract

Background: Fatty liver disease, especially non-alcoholic fatty liver disease (NAFLD), is commonly linked to obesity and metabolic syndrome. Yet, a growing number of non-obese individuals are now diagnosed with fatty liver, challenging conventional views of its pathogenesis. Known as lean NAFLD, it involves metabolic dysfunction despite a normal body mass index (BMI), making early detection vital to preventing the progression to steatohepatitis, fibrosis, and cirrhosis. Ultrasound (USG) is widely used for its accessibility, cost-effectiveness, and high sensitivity in detecting moderate to severe fatty liver changes. This study investigates the role of ultrasound in detecting fatty liver disease in non-obese individuals, assessing its diagnostic accuracy and correlation with metabolic parameters. Objectives: The study aims to evaluate the effectiveness of ultrasound in detecting fatty liver disease in non-obese individuals. It seeks to correlate ultrasound findings with biochemical markers, liver function tests, and metabolic parameters to assess the diagnostic value of sonographic grading in lean NAFLD. Subjects and Methods: This prospective observational study was conducted at a tertiary care hospital in Telanagana, India, enrolling 100 non-obese individuals (BMI <25 kg/m) suspected of having fatty liver disease based on clinical and biochemical evaluations. Participants underwent detailed metabolic assessments, liver function tests (LFTs), fasting lipid profiles, and ultrasound imaging for hepatic steatosis grading. Ultrasound findings were categorized into mild, moderate, and severe fatty liver based on echogenicity, hepatorenal contrast, and vascular blurring. Among the 100 non-obese participants, 47% were diagnosed with fatty liver via ultrasound: 32% had mild steatosis, 12% had moderate, and 3% had severe. Elevated ALT and AST levels showed significant correlation with ultrasound-confirmed fatty liver (p=0.002). Insulin resistance (HOMA-IR >2.5) was observed in 40% of participants with fatty liver, highlighting the metabolic link. Fasting triglyceride levels were notably higher in the fatty liver group (p=0.01). The diagnostic sensitivity and specificity of ultrasound for fatty liver detection were 81.2% and 85.5%, respectively, compared to metabolic markers. Conclusion: Ultrasound is a highly effective diagnostic tool for detecting fatty liver disease among non-obese individuals, strongly correlating with metabolic parameters and biochemical markers. The study suggests that lean NAFLD is closely associated with insulin resistance and dyslipidemia, underlining the need for early screening even in non-obese individuals. Given its non-invasive and cost-effective nature, ultrasound remains a crucial first-line modality for identifying fatty liver disease in non-obese populations at risk of metabolic dysfunction.