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Typical resistive index



Normal RI range




Hepatic 0.55-0.8

Low RI: steno-occlusive disease of the transplant hepatic artery, celiac artery stenosis, median arcuate ligament syndrome, HHT and portal hypertension.

High RI: chronic hepatocellular disease, transplant rejection,
hepatic venous congestion(chronic congestive hepatopathy),
nonocclusive hepatic artery hypoperfusion syndrome, postprandial state, advanced patient age, may transiently elevate within 72 hours after transplant 


About 0.6.
0.7 is the upper limit of normal



High RI: renal artery stenosis (if measured upstream from the stenosis) , ureteric obstruction, extreme hypotension, very young children, perinephric fluid collection, medical renal disease. 

High RI in transplant: acute tubular necrosis (ATN), acute or chronic transplant rejection, renal vein thrombosis, drug toxicity, renal artery stenosis (if measured upstream from the stenosis), ureteric obstruction, perinephric fluid collection.





RI decrease from 0.76 to 0.6 during pregnancy. S/D ratio decrease from 3.5 to 2.5 during pregnancy


RI should not be over 0.76 after 30 weeks.
S/D ratio should not be over 3 after 30 weeks.

Abnormal umbilical artery Doppler is a marker of uteroplacental insufficiency and consequent intrauterine growth restriction (IUGR) or suspected pre-eclampsia. 



Umbilical arterial S/D ratio (SDR): systolic velocity / diastolic velocity.

Resistive index (RI): (PSV – EDV) / PSV