Definition:

Zone or rim of peri-observation enhancement in the late arterial phase or early portal venous phase occurring after rapid dissipation of contrast material from an arterial phase hyperenhancing mass.

Usage:

• Applies to masses that diffusely hyperenhance in the arterial phase initially and then develop a zone or rim of peri-lesional enhancement as the enhancement of the mass itself declines.
• Corona enhancement usually fades to isoenhancement in the portal venous phase or delayed phase.
• Corona enhancement may have variable thickness and uniformity. It may be circumferential or eccentric/non-symmetric.
• Does not apply to masses without diffuse arterial phase hyperenhancement or to masses without rapid reduction in enhancement after the arterial phase.
• Corona enhancement is an ancillary feature that favors malignancy.
  • Corona enhancement specifically favors HCC as opposed to malignancy in general

• Do not characterize as corona enhancement

• Corona enhancement is attributed to early drainage of contrast material from hypervascular tumor such as HCC (or metastasis) into surrounding sinusoids/portal venules.

• Corona enhancement is seen most frequently if multiple arterial phases are acquired with high temporal resolution. It is seen infrequently if a single arterial phase is acquired.
• Presence of corona enhancement differentiates hypervascular tumor (e.g., HCC) from vascular pseudolesion (e.g., arterio-portal shunt).
• In masses with diffuse arterial phase hyperenhancement, corona enhancement and capsule appearance may overlap in appearance. If rim enhancement occurs in the arterial phase or portal venous phase and subsequently fades in later phases, characterize as corona enhancement. If rim enhancement increases in portal venous phase and delayed phase, characterize as capsule appearance.
• Corona enhancement associated with HCC may overlap in appearance with peri-lesional perfusional alterations associated with rapidly enhancing hemangiomas. If the mass itself fades to isoenhancement in the portal venous or delayed phase or “washes out” to hypoenhancement (i.e., the mass may be an HCC), characterize as corona enhancement. If the mass shows persistent delayed enhancement approximately paralleling that of the blood pool (i.e., the mass is definitely or probably a rapidly enhancing hemangioma), do not characterize as corona enhancement.