Accuracy of Ultrasound for Fatty Liver Assessment

Metabolic dysfunction-associated steatotic liver disease (MASLD) is increasingly prevalent, particularly among individuals with obesity and Type 2 diabetes. Early identification of MASLD is critical, yet access to formal imaging is often limited in primary care. Point-of-care ultrasound (POCUS) with the Ultrasound Fatty Liver Index (US-FLI), a semi-quantitative scoring tool, has demonstrated strong diagnostic accuracy but remains underutilized and is rarely included in standard POCUS training. This pilot study aimed to evaluate the diagnostic performance of US-FLI when performed by a novice POCUS user to explore its potential role as a screening tool for MASLD.

In a prospective convenience cohort (n = 65), US-FLI scores from a novice POCUS user were compared to radiologist-interpreted abdominal imaging. Sensitivity, specificity, positive predictive value, negative predictive value (NPV), and area under the receiver operating characteristic curve were calculated.

Fifteen patients (23%) had confirmed fatty liver disease on standard imaging. The novice user achieved a sensitivity of 0.87, specificity of 0.32, positive predictive value of 0.28, and NPV of 0.89. The area under the receiver operating characteristic curve was 0.61 (95% CI: 0.54-0.67). Raising the US-FLI threshold improved specificity but lowered sensitivity: ≥3 balanced sensitivity (0.73) and specificity (0.62), whereas ≥5 maximized specificity (0.96) at the expense of reduced sensitivity (0.27).

POCUS using US-FLI may serve as a rapid, noninvasive screening approach with high sensitivity and NPV, suggesting potential utility for ruling out MASLD in primary care settings. Larger studies in more diverse patient populations are needed to further validate these findings.