Table 1. OPTN classification scheme for the categorization of HCC.

Adapted from Wald C et al.39

OPTN class; description	Comment
0; incomplete or technically inadequate exam	Repeat study
1; no evidence of HCC	Routine surveillance in appropriate population
2; benign lesion or diffuse parenchymal abnormality	Routine surveillance in appropriate population
3; indeterminate lesion	Follow-up imaging
4; intermediate lesion – meets some criteria for HCC but not diagnostic	Short term follow-up suggested +/- biopsy
5; meets diagnostic criteria for HCC, further divided into subgroups
5A; ≥1 cm and <2 cm on late arterial or portal venous phase images	Increased contrast enhancement in late hepatic arterial phase AND washout during later phases of contrast enhancement AND peripheral rim enhancement (capsule or pseudocapsule)
5A-g; same size criteria as 5A but lesion grows in size	Increased contrast enhancement in late hepatic arterial phase AND maximum diameter increase by 50% or more documented on serial MRI or CT obtained ≤6 months apart – does not apply to ablated lesions
5B; ≥2 cm and ≤5 cm	Increased contrast enhancement in late hepatic arterial phase AND one of the following: Washout during later contrast phases Late capsule or pseudocapsule enhancement Growth by 50% or more documented on serial CT or MR images obtained ≤6 months apart – does not apply to ablated lesions Positive biopsy
5T; “treated” lesions	Past liver-directed therapy for OPTN 5 HCC or biopsy-proven HCC with any residual lesion
5X; ≥5 cm	Increased contrast enhancement in late hepatic arterial phase AND either washout during later contrast phases OR capsule or pseudocapsule enhancement