Hepatic arterial resistive index

The resistive index (RI) is the commonest Doppler parameter used for hepatic arterial evaluation. The usual range in normal, as well as post-transplant individuals, is between 0.55 and 0.8.

It is measured by:

RI = (peak systolic velocity - end diastolic velocity)/peak systolic velocity

Hepatic arterial resistive index is most often assessed during evaluation of a liver transplant.  In this setting, a low RI is usually more specific for disease than a high RI (the opposite situation from a renal transplant) 5.

Low RI: more specific for disease in a liver transplant, a low RI may result from:

  • proximal hepatic artery narrowing (concerning for a stenosis of the hepatic artery anastomosis, a serious complication)
  • peripheral vascular shunts (arteriovenous or arterioportal)

High RI: less specific for disease in a liver transplant, a high RI may result from:

  • microvascular compression or disease
    • chronic hepatocellular disease
    • transplant rejection
    • hepatic venous congestion
  • physiologic
    • postprandial state
    • advanced patient age

A high RI can be classified into four types 4:

  • type I: RI >0.80 with continuous blood flow in the diastolic phase
  • type II: RI = 1, complete absence of the diastolic signal and preserved systolic velocity
  • type III: absence of diastolic signal and diminished systolic velocity
  • type IV: undetectable Doppler flow
Ultrasound - general index
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Article information

rID: 9704
Synonyms or Alternate Spellings:
  • Hepatic artery RI
  • Hepatic artery resistive index
  • Hepatic artery RIs
  • Hepatic artery resistive indices
  • Hepatic arterial resistive indices

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