What is the interpretation of a liver scan (hepatic ultrasonography)?

From the Guidelines

Liver scan interpretation should be guided by a systematic approach, incorporating clinical context, laboratory values, and imaging findings to identify abnormalities and inform clinical management. When interpreting liver scans, it is essential to examine the scan for overall liver size, contour, and density, as well as look for focal lesions, diffuse changes, and vascular structures 1. The enhancement pattern after contrast administration is also crucial in differentiating benign from malignant lesions, with benign lesions typically showing uniform enhancement and malignant lesions demonstrating peripheral enhancement with central washout.

Key considerations in liver scan interpretation include:

• Evaluating the biliary system for dilation or obstruction
• Correlating laboratory values like liver enzymes, bilirubin, and tumor markers with imaging findings
• Comparing current findings with previous scans to assess for progression or regression of disease
• Using various imaging modalities, including ultrasound, CT, and MRI, each with specific advantages, such as ultrasound for initial screening, CT for better anatomical detail, and MRI for superior soft tissue characterization 1

According to the EASL clinical practice guidelines on non-invasive tests for evaluation of liver disease severity and prognosis, liver stiffness measurement can be obtained by different methods, including vibration-controlled transient elastography (TE), point-shear wave elastography (pSWE), and bidimensional shear wave elastography (2D-SWE) 1. However, liver stiffness is a physical property of the tissue that depends not only on the amount of liver fibrosis but also on several other factors, such as inflammation, obstructive cholestasis, food ingestion, exercise, or venous congestion, which should be carefully excluded to avoid misdiagnosis 1.

A minimum of 3 hours fasting is required for a correct measurement and interpretation of liver stiffness. Additional details and recommendations can be found in the previous version of the EASL CPGs on NITs for chronic liver disease 1. The interpretation of liver scans should conclude with a clear impression of findings and recommendations for further management or follow-up imaging when appropriate, taking into account the clinical context and laboratory values, as emphasized by the American Gastroenterological Association medical position statement on the evaluation of liver chemistry tests 1.

From the Research

Liver Scan Interpretation

Liver scan interpretation is a crucial step in diagnosing and managing liver diseases. The following points highlight the key aspects of liver scan interpretation:

• Abnormal liver test results can be categorized into hepatocellular, cholestatic, and infiltrative diseases 2
• Hepatocellular disease is characterized by transaminase increases greater than 5 times the upper limit of normal, with alkaline phosphatase levels usually increased less than 2 to 3 times the upper limit of normal 2
• Cholestatic disease is characterized by an increase in the alkaline phosphatase level that is 3 to 5 times greater than the upper limit of normal, with only a mild increase of transaminases 2
• Infiltrative diseases of the liver, such as lymphoma or granulomatous hepatitis, are characterized by an increase in the alkaline phosphatase level that is disproportionate to the bilirubin level 2

Imaging Techniques

The following imaging techniques are used in liver scan interpretation:

• Ultrasonography is the best initial imaging technique for the liver 2
• Endoscopic retrograde cholangiopancreatography (ERCP) is recommended if biliary dilatation is noted on ultrasonography 2
• Liver biopsy is often needed for a precise diagnosis in patients with long-term increases in liver test results 2

Treatment Options

The following treatment options are available for liver diseases:

• Ursodeoxycholic acid (UDCA) is currently the only established drug for the treatment of chronic cholestatic liver diseases 3
• UDCA has cytoprotective, anti-apoptotic, membrane stabilizing, anti-oxidative, and immunomodulatory effects 3
• The use of UDCA in non-cholestatic liver diseases, such as non-alcoholic fatty liver disease and autoimmune hepatitis, has shown promise in improving liver biochemistry, but its long-term effects are unclear 4