LI-RADS radiation-based treatment response algorithm for HCC: what to know and how to use it

Area of Science:

• Hepatobiliary imaging
• Interventional oncology
• Radiology

Background:

• Locoregional treatments (LRT) for hepatocellular carcinoma (HCC) are evolving, with increasing use of radiation-based therapies like selective internal radiation therapy (SIRT), transarterial radioembolization (TARE), external beam radiation therapy (EBRT), and stereotactic body radiation therapy (SBRT).
• Assessing treatment response after these therapies is complex due to treatment-related liver changes, inflammation, and variable response timelines.
• The initial LI-RADS treatment response (LR-TR) algorithm, developed in 2017, encompassed all LRT, but lacked specificity for radiation-based modalities.

Purpose of the Study:

• To elucidate the changes in the updated LI-RADS TR algorithm specifically for radiation-based LRT in HCC.
• To provide a guide for utilizing the revised LR-TR algorithm.
• To illustrate expected and unexpected imaging findings following liver-directed therapies for HCC.

Main Methods:

• Review and analysis of the updated LI-RADS TR algorithm focusing on radiation-based therapies.
• Comparison of imaging patterns between radiation and non-radiation based therapies.
• Case-based illustration of imaging findings post-treatment.

Main Results:

• The updated LR-TR algorithm incorporates specific criteria to differentiate tumor response from treatment-related changes after radiation therapies.
• Recognizes distinct imaging patterns associated with SIRT, TARE, EBRT, and SBRT.
• Aims to improve the accuracy and consistency of treatment response assessment in HCC.

Conclusions:

• The revised LI-RADS TR algorithm offers a more nuanced approach to evaluating treatment response in HCC following radiation-based LRT.
• Accurate assessment is crucial for guiding subsequent management decisions in HCC patients.
• Understanding these updated guidelines aids radiologists in interpreting post-treatment imaging findings.