Periportal halo

Dr Craig Hacking and Dr Omar Bashir et al.

Periportal halo or periportal collar sign is a zone of low attenuation seen around the portal veins on contrast-enhanced CT or hypoechogenicity on liver US. Periportal halos may occur around the central portal veins or their peripheral branches and occurs on both sides of the portal triads.

This sign is seen when there is fluid accumulation or dilatation of lymphatics in the loose areolar tissue around the portal triads. This sign is nonspecific and can be seen in various conditions 1:

  • biliary dilatation, in which the low attenuation is seen on only one side of the portal triads
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Article information

rID: 16897
Section: Signs
Tag: cases
Synonyms or Alternate Spellings:
  • Periportal collar
  • Periportal halo sign
  • Peri-portal halo
  • periportal edema

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