Fatty Liver Ultrasound Findings and Interpretation

When diagnosing fatty liver disease, ultrasound imaging plays a crucial role in identifying key characteristics. Here are the primary ultrasound observations associated with fatty liver:

1. Increased Brightness in the Liver Parenchyma

The near-field echoes of the liver appear enhanced and dense, while the far-field echoes show signs of attenuation. This appearance is commonly referred to as "bright liver," a hallmark of hepatic steatosis.

2. Enhanced Contrast Between Liver and Kidney

A noticeable increase in echogenicity of the liver compared to the kidney is often observed. This increased liver-to-kidney contrast is a key indicator of fat accumulation in the liver.

3. Poor Visualization of Intrahepatic Vascular Structures

As fat accumulates in the liver cells, the vascular structures within the liver may become less distinct or difficult to visualize clearly during the ultrasound examination.

4. Mild to Moderate Hepatomegaly

In many cases, the liver may appear slightly or moderately enlarged, which is another common sign associated with fatty liver disease.

Ultrasound is a sensitive tool for detecting fatty liver, particularly when more than 30% of hepatocytes are affected by fat accumulation. When over 50% of liver cells are involved, the sensitivity of ultrasound for diagnosing fatty liver exceeds 95%. However, it is less effective in detecting mild cases, such as when only about 5% of liver cells are affected. In such early stages, alternative diagnostic methods like transient elastography (FibroScan with CAP measurement) may be more appropriate. Additionally, CT scans or MRI can be used, where a liver-to-kidney CT ratio of less than or equal to 1 is considered indicative of fatty liver disease. These imaging modalities offer higher sensitivity for detecting mild or early-stage steatosis.