Journal: Radiographics : a review publication of the Radiological Society of North America, Inc
This article reviews the updated 2024 CT/MRI LI-RADS treatment response (TR) algorithm for patients with hepatocellular carcinoma undergoing locoregional therapy.
Key points:
- Clinical context: Locoregional therapies (eg, ablation, embolization, radiation-based approaches) are used with curative intent, as bridge/downstaging to transplant, or for palliative tumor debulking. Post-treatment imaging is critical to distinguish complete response from residual or recurrent viable tumor, which directly informs subsequent therapy, transplant candidacy, and surveillance intensity.
- Problem addressed: Interpretation of post-treatment imaging is difficult because expected appearances vary by:
- Treatment modality: thermal, embolic, radiation-based
- Degree of response
- Time since therapy
This variability contributes to inconsistent reporting and management decisions.
- LI-RADS TR update:
- The 2024 algorithm refines and standardizes CT/MRI criteria for assessing tumor viability after locoregional therapy in primary liver malignancies.
- It now differentiates explicitly between:
- Non–radiation-based therapies: eg, ablation, embolization techniques
- Radiation-based therapies: eg, external beam or radioembolization, which often have more delayed and subtle imaging changes.
- Ancillary MRI features have been incorporated to increase sensitivity for viable tumor, addressing scenarios where classic arterial hyperenhancement or washout may be absent or equivocal.
- Clinical implications:
- More consistent and reproducible assessments of treated lesions.
- Better alignment of imaging reports with real tumor biology, particularly after radiation-based treatments.
- Clearer guidance for multidisciplinary decision-making regarding retreatment, transplantation, and surveillance, ultimately aiming to optimize outcomes for patients with HCC.