Table 3.

Liver Imaging-Reporting and Data System (LI-RADS)

Category	Concept	Imaging findings
LR 1	Definitely benign	Imaging features diagnostic of a benign entity or Definite disappearance at follow-up in the absence of treatment
LR 2	Probably benign	Imaging features suggestive but NOT diagnostic of a benign entity
LR 3	Intermediate probability for HCC Both HCC and benign entity have moderate probability	Not definite mass Includes nodule-like hepatic arterial phase hyperenhancement Definite mass Mass with hepatic arterial phase hypo- or isoenhancement <20 mm mass with ≤1 of following: washout, capsule, threshold growth ≥20 mm mass with none of following: washout, capsule, threshold growth Mass with hepatic arterial phase hyperenhancement <20 mm mass with none of following: washout, capsule, threshold growth
LR 4	Probably HCC High but not 100% probability of HCC	LR 4A (<20 mm mass) Mass with arterial phase hypo- or isoenhancement and ≥2 of following: “wash out”, “capsule”, threshold growth Mass with arterial phase hyperenhancement <10 mm mass with ≥1 of following: washout, capsule, threshold growth or 10–19 mm mass with only 1 of following: washout, capsule, threshold growth LR 4B (≥20 mm mass) LR 4B (≥20 mm mass) Mass with arterial phase hypo- or isoenhancement with ≥1 of following: wash out, capsule, threshold growth Mass with arterial phase hyperenhancement and none of following: washout, capsule, threshold growth
LR 5	Definitely HCC	LR 5A (10–19 mm mass) Mass with arterial phase hyperenhancement 10–19 mm mass with ≥2 of following: washout, capsule, threshold growth LR 5B (≥20 mm mass) Mass with arterial phase hyperenhancement ≥ 20 mm mass with ≥ 1 of following: washout, capsule, threshold growth LR 5V Definitely HCC with tumor in vein

HCC, hepatocellular carcinoma.