A liver ultrasound is a non-invasive imaging method that uses high-frequency sound waves to create real-time pictures of the liver and surrounding structures. This procedure is frequently used to assess the liver’s size, shape, and internal texture, providing initial clues about liver health. Understanding the language used in an ultrasound report helps patients demystify the visual findings that suggest whether the organ is functioning normally or is affected by disease. This article clarifies the visual signs a sonographer or radiologist looks for when determining if a liver ultrasound is abnormal.
The Baseline Appearance of a Healthy Liver
A healthy liver provides the visual standard against which potential disease is measured. In a normal ultrasound, the liver tissue (parenchyma) should appear uniform and smooth, a characteristic described as homogenous. The outer edges, or margins, are typically sharp and smooth, with no noticeable irregularities.
The brightness or shade of gray on the screen is called echogenicity, and a healthy liver displays medium echogenicity. The liver is often slightly brighter than the adjacent kidney cortex. This internal comparison helps the interpreting physician and provides a consistent reference point for assessing subtle changes in the liver tissue.
Interpreting Abnormal Liver Tissue Texture
When a liver is affected by diffuse disease, the uniform texture of the parenchyma changes significantly, indicating an overall structural problem. One common diffuse abnormality is fatty infiltration, or steatosis, which involves the accumulation of fat within liver cells. On an ultrasound, a fatty liver appears hyperechoic, meaning it is noticeably brighter than normal tissue, often described as a “bright liver.”
As the severity of steatosis increases, the brightness of the liver tissue can become pronounced, obscuring the visibility of deeper structures, such as blood vessel walls and the diaphragm. In contrast, chronic liver disease leading to scarring (fibrosis or cirrhosis) causes the liver texture to become coarse or heterogeneous. This scarring often results in an irregular, lumpy, or nodular surface contour on the organ, which is an indicator of advanced disease. Cirrhosis can also change the liver’s shape, sometimes causing the right lobe to shrink while the caudate lobe enlarges.
Identifying Focal Lesions and Masses
Beyond changes to the entire organ’s texture, an abnormal ultrasound may reveal distinct, localized spots within the liver parenchyma, referred to as focal lesions or masses. Their appearance is characterized by echogenicity and border definition. A simple liver cyst, which is a fluid-filled sac, typically appears anechoic (completely black) because sound waves pass straight through the liquid.
Simple cysts are usually benign, characterized by thin, smooth walls and clear, well-defined boundaries. Solid, benign masses, such as a hemangioma (a tangle of blood vessels), often appear uniformly hyperechoic (bright) with sharp, well-demarcated edges. Conversely, masses that raise suspicion, including malignant tumors, tend to exhibit irregular features.
Suspicious masses may have ill-defined borders, mixed or heterogeneous echogenicity, or appear darker (hypoechoic) than the surrounding liver tissue. The presence of internal blood flow within a solid mass, assessed using Doppler ultrasound, also helps characterize the lesion. While ultrasound can suggest the nature of a focal lesion, further imaging or biopsy is necessary for a definitive diagnosis.
Associated Abnormalities Beyond the Liver
Liver disease frequently affects surrounding organs and fluid distribution, meaning an abnormal liver ultrasound often includes findings outside the liver. One such finding is the accumulation of free fluid within the abdominal cavity, known as ascites. On the ultrasound image, this fluid appears anechoic (black), often pooling around the liver or between loops of the bowel.
Another common associated sign, particularly in cases of advanced cirrhosis, is splenomegaly, an enlargement of the spleen. Increased size suggests elevated pressure in the portal vein system, a condition called portal hypertension. The ultrasound also examines the bile ducts; an abnormality may be indicated by biliary dilation, where the ducts are widened. Widened bile ducts suggest an obstruction, such as from a gallstone or a mass, which prevents the normal flow of bile out of the liver.