Table summarizes categorization as LR-3,LR-4, or LR-5 masses that are neither definite benign entities nor probable benign entities, that lack features that favor non-HCC malignancy, and that are not associated with tumor in vein.

To assign a LI-RADS category using Table:
Characterize each mass as follows:

• Degree of arterial phase enhancement

o Arterial phase hypo- or isoenhancement vs. arterial phase hyperenhancement

• Diameter

o <20mm vs. ≥ 20mm if arterial phase hypo- or isoenhancing
o <10mm vs. 10-19mm vs. ≥ 20mm if arterial phase hyperenhancing

• Number of the following features: “washout”, “capsule”, threshold growth

o None, one, two or more

Then select the corresponding cell in Table

Comments:
Compared to larger masses and masses with arterial phase hyperenhancement, smaller masses and masses with arterial phase hypo- or isoenhancement must satisfy stricter criteria to be assigned an equivalent LR category. Masses with arterial phase hypo- or isoenhancement cannot be categorized LR-5. Masses with diameter <10mm cannot be categorized LR-5.

• Observations with diameter 10-19mm,arterial hyperenhancement and one major feature may be characterized as LR-5g or LR-5us rather than LR-4 under specific circumstances

• Observations with arterial hyperenhancement, diameter 10-19mm, and ≥50% diameter increase in ≤ 6 months meet criteria for OPTN 5A-g. In this circumstance, these observations should be categorized LR-5g rather than LR-4.

In those patients who undergo ultrasound surveillance at a center that uses AASLD guidelines, observations with arterial hyperenhancement, washout appearance, and visibility on an antecedent surveillance ultrasound meet AASLD HCC criteria. In this circumstance, these observations should be categorized LR-5us rather than LR-4.

Features seen on CT and MR can be integrated to yield the final LI-RADS category. If this is done, it must be explicitly stated in the radiology report.