Periportal halo (liver)

Periportal halo or periportal collar sign refers to a zone of low attenuation seen around the portal veins on contrast-enhanced CT or hypoechogenicity on liver ultrasound. It likely represents periportal edema, which is often used as a synonymous term. Periportal haloes may occur around the central portal veins or their peripheral branches and occur on both sides of the portal triads.

Pathology

Etiology

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 non-specific and can be seen in various conditions :

• congestive cardiac failure (CCF)
• secondary cardiac congestion
• acute hepatitis, particularly viral hepatitis
• lymphadenopathy at the porta hepatis causing lymphatic obstruction
• liver transplant and liver transplant rejection
• bone marrow transplantation (BMT)
• blunt hepatic trauma
• blunt abdominal trauma and aggressive fluid resuscitation
• cholangitis
• primary biliary cholangitis (PBC) (on MRI)
• acute pyelonephritis

Differential diagnosis

• biliary dilatation, in which the low attenuation is seen on only one side of the portal triads
  • biliary dilatation and periportal halo may - of course - both be present

See also

• periportal hypoechogenicity
• periportal hyperechogenicity

Siehe auch:

• Hepatitis
• intrahepatische Cholestase
• extramedulläre Hämatopoese in der Leber

und weiter:

• Cholestase