Resistance index Description 0 Continuous flow 1 Systolic flow, but no diastolic flow >1 Reversed diastolic flow The RI is altered not by vascular resistance alone but by the combination of vascular resistance and vascular compliance. Normal mean renal artery RI for an adult is 0.6 with 0.7 the upper limit of normal. In children, RI commonly exceeds 0.7 through 12 months of age and can remain above 0.7 through 4 years of age.
Arterial resistivity index
Arterial input function
Coronary flow reserve
Pressure reactivity index
Vascular resistance
PAH clearance
Arteriovenous oxygen difference
Coronary perfusion pressure