US Liver Imaging Reporting and Data System Version 2017: A Systematic Review and Meta-Analysis.

Area of Science:

• Radiology and Imaging Science
• Hepatology and Liver Disease Research
• Medical Data Analysis and Meta-Research

Background:

• The US Liver Imaging Reporting and Data System (LI-RADS) categorizes findings and assesses image quality (visualization score).
• US-3 (positive category) and VIS-C (severe limitations) significantly influence patient management decisions.
• Understanding the distribution and implications of these categories is crucial for clinical practice.

Purpose of the Study:

• To determine the distribution of US LI-RADS categories and visualization scores.
• To estimate the prevalence of hepatocellular carcinoma (HCC) and overall malignancy within the US-3 category.
• To identify factors associated with severe image quality limitations (VIS-C).

Main Methods:

• A systematic meta-analysis was conducted on 15 studies (39,166 US examinations) published between January 2017 and September 2023.
• Data extracted included US LI-RADS category and visualization score distributions, HCC/malignancy rates in US-3, and VIS-C associated variables.
• Random-effects models were employed for meta-analysis.

Main Results:

• 89.7% of US examinations were categorized as US-1 (negative), 4.4% as US-2 (subthreshold), and 5.9% as US-3 (positive).
• Among US-3 cases, 25.9% had probable/definite HCC and 26.4% had overall malignancy.
• Severe image quality limitations (VIS-C) occurred in 7.8% of examinations and were associated with obesity (OR 2.37), NAFLD (OR 2.24), and Child-Pugh B/C cirrhosis (OR 2.41).

Conclusions:

• The majority of surveillance US examinations are negative (US-1) and of adequate quality (VIS-A/B).
• A significant proportion (26%) of US-3 findings represent HCC, underscoring the importance of this category.
• Obesity, NAFLD, and advanced liver disease (cirrhosis) are key factors contributing to poor ultrasound image quality (VIS-C).