Definition:

Imaging features that modify likelihood of HCC. In isolation, these features do not permit reliable categorization of observations and hence are considered ancillary. 

Comments:

Radiologists may at their discretion apply ancillary features to adjust LI-RADS category as follows:

• Features that may favor malignancy to upgrade category by one or more categories (up to but not beyond LR-4).
  • Ancillary features cannot be used to upgrade category to LR-5 to maintain congruency with OPTN.
  • Ancillary features that may favor malignancy can favor malignancy in general or specifically favor HCC
• Features that may favor benignity to downgrade category by one or more categories.

Features that may favor malignancy:

• Hepatobiliary phase hypointensity
• Transitional phase hypointensity
• Mild-moderate T2 hyperintensity
• Restricted diffusion
• Distinctive rim*
• Corona enhancement*
• Mosaic architecture*
• Nodule-in-nodule architecture*
• Intra-lesional fat*
• Lesional iron sparing
• Lesional fat sparing
• Blood products
• Diameter increase less than threshold growth

*Features that specifically favor HCC as opposed to malignancy in general.

Features that may favor benignity:

• Homogeneous marked T2 hyperintensity
• Homogeneous marked T2 or T2* hypointensity
• Hepatobiliary phase isointensity
• Undistorted vessels
• Parallels blood pool enhancement
• Diameter reduction
• Diameter stability ≥ 2 years