Periportal halo

Periportal halo or periportal collar sign is a zone of low attenuation seen around the portal vein on contrast-enhanced CT. Periportal halos may occur around the central portal veins or their peripheral branches. 



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:

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Article information

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

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