Gastrointestinal and Hepatobiliary · Hepatocellular carcinoma · v2024
LI-RADS CT/MRI Treatment Response Assessment v2024
LI-RADS CT/MRI Treatment Response Assessment v2024 provides separate lesion-level response algorithms for hepatocellular carcinoma treated with nonradiation- and radiation-based locoregional therapies.
Purpose
To standardise lesion-level assessment of path-proven or presumed hepatocellular carcinoma after locoregional treatment using post-treatment multiphase CT or MRI in patients eligible for LI-RADS.
| Algorithm | LR-TR category | Imaging criterion | Interpretation |
|---|---|---|---|
| Both | LR-TR Nonevaluable | Masslike enhancement cannot be assessed because of image degradation, phase omission or another technical limitation | Treatment response cannot be evaluated |
| Both | LR-TR Nonviable | No masslike enhancement within the treated lesion or along its margin | No imaging evidence of viable tumour |
| Nonradiation | LR-TR Equivocal | Uncertainty about the presence or morphology of masslike enhancement | Viability remains uncertain |
| Nonradiation | LR-TR Viable | Masslike enhancement of any degree in any contrast-enhanced phase | Imaging evidence of viable tumour |
| Radiation | LR-TR Nonprogressing | Masslike enhancement that is stable or decreased in size over time after treatment | Expected post-radiation evolution without imaging progression |
| Radiation | LR-TR Viable | Masslike enhancement that is new or increased in size over time after treatment | Imaging evidence of viable tumour |
How to use it
- Use the nonradiation algorithm after radiofrequency, microwave, cryoablation or ethanol ablation, bland embolisation, conventional or drug-eluting bead TACE, and when assessing recurrence at a surgical margin.
- Use the radiation algorithm after TARE or SBRT; change in the size of masslike enhancement over time is central to categorisation.
- Optional MRI ancillary features favouring viability are diffusion restriction and mild-to-moderate T2 hyperintensity; these do not constitute a separate LR-TR category.
- Ancillary features may upgrade LR-TR Equivocal to Viable after nonradiation therapy, or LR-TR Nonprogressing to Viable after radiation therapy when the required spatial and temporal criteria are met.
- Apply the diagnostic CT/MRI LI-RADS algorithm, rather than the treatment-response algorithm, to new or untreated observations outside the treatment zone.
Common mistake
Do not classify persistent enhancement after TARE or SBRT as LR-TR Viable solely because enhancement remains present. Stable or decreasing masslike enhancement is LR-TR Nonprogressing; new or increasing masslike enhancement indicates LR-TR Viable.
Exam pearl
Nonradiation response should be immediate: Equivocal is used when masslike enhancement is uncertain. Radiation response evolves over time: Nonprogressing is used when masslike enhancement is stable or decreasing.
Viva questions
- What is the purpose of LI-RADS Treatment Response Assessment?
- It standardises lesion-level assessment of presumed or proven hepatocellular carcinoma after locoregional treatment using post-treatment multiphase CT or MRI.
- What are the LR-TR categories in the nonradiation algorithm?
- They are LR-TR Nonevaluable, Nonviable, Equivocal and Viable.
- What are the LR-TR categories in the radiation algorithm?
- They are LR-TR Nonevaluable, Nonviable, Nonprogressing and Viable. Equivocal is not a radiation-algorithm category.
- What is the major imaging feature of viability in LI-RADS TRA v2024?
- The major feature is masslike enhancement of any degree in any contrast-enhanced phase.
- How is stable masslike enhancement classified after TACE and after TARE?
- After TACE, definite masslike enhancement is LR-TR Viable. After TARE, masslike enhancement that is stable or decreased in size over time is LR-TR Nonprogressing.
- Which MRI ancillary features favour viability?
- Diffusion restriction and mild-to-moderate T2 hyperintensity favour viability. They may support an optional upgrade to LR-TR Viable when present in the required area and, after radiation therapy, show the required temporal increase.
- When should LR-TR Nonevaluable be assigned?
- Assign LR-TR Nonevaluable when masslike enhancement cannot be assessed because the required imaging is technically inadequate, degraded or incomplete.
- What is the principal interpretation pitfall after radiation-based therapy?
- Persistent enhancement should not automatically be labelled viable. After TARE or SBRT, stable or decreasing masslike enhancement is LR-TR Nonprogressing, whereas new or increasing masslike enhancement is LR-TR Viable.