LI-RADS

Liver Imaging Reporting and Data System

Current: A family at different version years: CT/MRI Diagnostic v2018; CT/MRI Treatment Response v2024 (split into non-radiation and radiation pathways); US Surveillance v2024; CEUS Diagnostic v2017 + CEUS Treatment Response v2024American College of Radiology (ACR)
LiverCTMRUltrasound

LI-RADS is a standardized framework, maintained by the ACR, for describing, categorizing, and reporting liver findings in people at elevated risk of hepatocellular carcinoma (HCC). Rather than one rulebook, it is a family of independently versioned algorithms for different jobs and imaging methods: diagnosing untreated lesions on CT/MRI and on contrast-enhanced ultrasound, screening with grayscale ultrasound, and judging whether a treated tumor still has living tissue. Because HCC can often be diagnosed by imaging alone in at-risk patients, these algorithms feed directly into clinical and transplant decisions — and the tracks evolve on their own timelines, so different modalities sit at different version years.

Version history & what changed

CT/MRI Diagnostic

  1. CT/MRI v20182018Current

    The current diagnostic algorithm for untreated observations on multiphase CT and MRI; harmonized LI-RADS with AASLD guidance and refined thresholds such as the definition of threshold growth and the size/enhancement rule contributing to the definite-HCC category. Not superseded as of mid-2026.

  2. CT/MRI v20172017

    Prior diagnostic release; brought major structural alignment and expanded the treatment-response and tumor-in-vein concepts before the 2018 refinements.

  3. v20142014

    Early iteration in the original CT/MRI lineage, expanding the descriptor lexicon and category logic.

  4. v20132013

    Early refinement of the original system.

  5. v2011 (original)2011

    The first LI-RADS release, establishing the LR-1 through LR-5 ordinal concept for liver observations.

CT/MRI Treatment Response (TRA)

  1. CT/MRI TRA v2024 (non-radiation + radiation)2024-11Current

    Split the single 2017 treatment-response algorithm into two pathways because tumors look different after radiation-based therapies (radioembolization, stereotactic radiotherapy) than after non-radiation therapies (ablation, chemoembolization). The non-radiation pathway centers viability on mass-like enhancement with optional MRI ancillary features for equivocal lesions; the radiation pathway recognizes treated lesions can evolve slowly without meaning failure.

  2. TRA v20172017

    The original single treatment-response algorithm (viable / equivocal / nonviable), applied uniformly across therapy types; later judged too coarse for radiation-based therapies, prompting the 2024 split.

US Surveillance

  1. US Surveillance v20242024Current

    Refreshed the grayscale-ultrasound screening track to align with 2023 AASLD HCC guidance; folded serum AFP trend and the severe-limitation visualization score into management advice and clarified follow-up after non-positive exams. Reported to raise sensitivity at some cost to specificity.

  2. US LI-RADS v20172017

    First standardized grayscale-ultrasound surveillance track, introducing the US category and visualization-score concepts; superseded by US Surveillance v2024.

CEUS

  1. CEUS Diagnostic v20172017Current

    The current contrast-enhanced-ultrasound diagnostic algorithm (a revision of the 2016 release); categorizes untreated liver observations using contrast kinetics specific to microbubble agents. Notably NOT renumbered to 2024 — only the CEUS treatment-response track was added in 2024.

  2. CEUS Treatment Response v2024 (non-radiation)2024Current

    A new CEUS treatment-response algorithm for post-non-radiation locoregional therapy (ablation, chemo/bland embolization), assessing residual living tumor by enhancement with viable / equivocal / nonviable readouts — distinct from the older CEUS diagnostic algorithm.

  3. CEUS v20162016

    The first official ACR CEUS LI-RADS; quickly revised to v2017.

How the system is structured

The diagnostic tracks (CT/MRI and CEUS) place each liver observation on an ordinal ladder from LR-1 (almost certainly benign) up to LR-5 (almost certainly HCC), with intermediate steps, plus a separate LR-M flag for malignancy that doesn't look HCC-specific and an LR-TIV flag for tumor that has invaded a vein; LR-NC covers observations that can't be categorized. The treatment-response tracks instead report whether a treated lesion appears viable, equivocal, or nonviable. The surveillance track uses a small set of result categories paired with a separate score for how well the liver could be seen. Consult the official ACR LI-RADS documents for the exact criteria, thresholds, and decision rules.

  • LR-1Very confident the finding is benign.
  • LR-2Likely benign.
  • LR-3Genuinely indeterminate risk of HCC.
  • LR-4Leaning toward HCC but short of certainty.
  • LR-5Confident this is HCC.
  • LR-MMalignant-appearing but not specifically HCC-looking.
  • LR-TIVTumor extending into a vein.
  • LR-NCCannot be categorized (technical / image-quality limits).
  • LR-TR (Treatment Response)After treatment: nonviable, equivocal, or viable tumor (plus a nonevaluable option).
  • US Surveillance resultNegative, subthreshold, or positive screen — with a separate visualization score for how well the liver could be assessed.

These are our plain-language summaries. For the exact criteria, thresholds, and management rules, see the official source.

Latest on LI-RADS

Body / AbdominalInterventional (IR)GeneralGuidelineTrainee

Brazilian multidisciplinary consensus standardizes hepatocellular carcinoma diagnosis, assessment, and staging

A 43-expert Brazilian consensus issued 18 recommendations for hepatocellular carcinoma (HCC) work-up: standardized LI-RADS imaging diagnosis, biopsy indications, liver function and portal hypertension assessment, staging, and multidisciplinary care.

Arquivos brasileiros de cirurgia digestiva : ABCD = Brazilian archives of digestive surgery
Body / AbdominalResearchTrainee

Early Weak Washout on CEUS Predicts HCC in LR-M Nodules: Preliminary Data

Rapid onset of weak washout before 1 min and persisting to 5 min on CEUS identified HCC within LR-M nodules with 77.6% sensitivity and 64.7% specificity (n=100). Adding non-rim APHE increased specificity to 80.4% but lowered sensitivity to 61.2%.

Abdominal radiology (New York)
Body / AbdominalAI / InformaticsResearchTrainee

DLIR/dual-energy CT non-inferior to MRI for HCC LI-RADS major features

DLIR-H/50-keV dual-energy CT protocol showed non-inferiority to MRI for detecting arterial phase hyperenhancement (APHE) and washout in HCC, offering an alternative when MRI access is limited.

Abdominal radiology (New York)
Body / AbdominalInterventional (IR)Research

Three EOB-MRI features predict complete response to TACE in HCC >2 cm

Retrospective study: combined model of tumor diameter, irregular border, and enhancing capsule on pretreatment EOB-MRI predicted complete response after TACE in HCC >2 cm (AUC 0.72, 95% CI 0.65–0.79).

Reporting systems & Fleischner (PubMed)
Body / AbdominalInterventional (IR)AI / InformaticsResearchTrainee

CT and MRI Advances for Y90 Radioembolization in HCC

Review: CT/MRI biomarkers optimize TARE planning and HCC response assessment; enhancement-based criteria outperform size-based, LI-RADS TRA v2024 adds non-progressing category, radiomics/body composition metrics prognostic, but need validation.

Radiology AI literature (PubMed)
Body / AbdominalGeneralInterventional (IR)ResearchTrainee

Noncontrast abbreviated MRI inferior to full-sequence MRI for post-TACE HCC surveillance

In a retrospective study of 195 patients, noncontrast abbreviated MRI (NC-AMRI) showed lower sensitivity (78.3% vs 92.4%) and specificity (79.6% vs 95.1%) than full-sequence MRI for detecting intrahepatic HCC recurrence after TACE, hindering its utility as a standalone monitorin…

Reporting systems & Fleischner (PubMed)
Body / AbdominalGeneralResearch

Lower HCC risk in small hypervascular LR-3 nodules without ancillary features

In a retrospective study of 166 hypervascular LI-RADS 3 observations <2 cm without ancillary features, only 3.0% (95% CI 0–6.1%) progressed to HCC at 1 year, far lower than the ~one-third rate often cited for the overall LR-3 category.

Reporting systems & Fleischner (PubMed)
Body / AbdominalGeneralEducationTrainee

LI-RADS overview on Radiology Assistant

The Radiology Assistant provides an educational overview of LI-RADS for standardized liver imaging reporting in patients at risk for hepatocellular carcinoma.

Radiology Assistant

How it compares

LI-RADS overlaps with other HCC pathways but is more granular. The transplant-allocation system used by OPTN/UNOS defines HCC eligibility by size/enhancement classes, and LR-5 is designed to map cleanly onto that 'definite HCC' tier while adding intermediate categories the allocation system lacks. AASLD guidance incorporates LI-RADS terminology, whereas Europe's EASL and Asia's APASL/KLCA frameworks use their own diagnostic wording and sometimes accept slightly different imaging combinations as diagnostic. Compared with simply calling a lesion 'suspicious,' LI-RADS' explicit ordinal scale is what enables probability-calibrated management and research.

Evidence & controversy

Across pooled analyses, the definite-HCC category (LR-5) consistently shows high specificity and strong positive predictive value, with more moderate sensitivity because many true HCCs land in lower categories — a deliberate trade-off to avoid over-calling. Diagnostic meta-analyses of CT/MRI LI-RADS report good overall performance but note inter-reader variability concentrated in the intermediate LR-3/LR-4 tiers; for CEUS, pooled LR-5 specificity is excellent with lower sensitivity. The system is widely adopted in North American practice and embedded in AASLD guidance. Common critiques are the limited standalone sensitivity of LR-5, ambiguity of the indeterminate categories, and the operational burden of multiple separately versioned algorithms.

Frequently asked questions

Is LI-RADS one algorithm?
No — it is a family of algorithms maintained by the ACR, each for a specific task and imaging method, and each carrying its own version year.
What is the current CT/MRI diagnostic version in 2026?
v2018; it has not been renumbered, even though the treatment-response and ultrasound tracks were updated to 2024.
Who is LI-RADS for?
Patients at elevated HCC risk (for example, cirrhosis or chronic hepatitis B); it is not intended for the general population or for non-HCC liver cancers.
Why was the 2024 treatment-response algorithm split in two?
Because tumors treated with radiation-based therapies evolve and enhance differently than those treated with ablation or embolization, so a single rule produced misleading 'viable' calls.
Is CEUS LI-RADS at version 2024?
Only its new treatment-response algorithm is; the CEUS diagnostic algorithm remains v2017.

Glossary

HCC
Hepatocellular carcinoma, the primary liver cancer LI-RADS targets.
Observation
A distinct finding seen on imaging that receives a LI-RADS category.
APHE (arterial-phase hyperenhancement)
A lesion enhancing more than surrounding liver during the arterial contrast phase — a core HCC clue.
Washout
A lesion becoming relatively darker than background liver on later phases.
Threshold growth
A defined amount of size increase over time used as a malignancy signal.
LR-TIV
The designation for tumor that has grown into a vein.
Visualization score
A grade of how well the liver could be assessed on surveillance ultrasound, independent of any finding.
Locoregional therapy
Liver-directed treatments such as ablation, chemoembolization, or radioembolization that the treatment-response tracks evaluate.

Resources & links

Written by RadPigeon Editorial Team, Radiology news editorial teamMedical review pending
Last reviewed: 29 Jun 2026Last changed: 29 Jun 2026

RadPigeon is an independent radiology news digest and is not affiliated with or endorsed by American College of Radiology (ACR). “LI-RADS” is a trademark of its owner and is named here only to refer to the system. Always consult the official source for the exact, current criteria.