Doppler parameter calculated as (peak systolic velocity minus end diastolic velocity) divided by peak systolic velocity
Expansion
Resistive Index
Purpose
Assesses vascular resistance; resistive index greater than 0.8 suggests elevated resistance (stenosis, pathology)
Clinical Context
Resistive index equals (peak systolic velocity minus end diastolic velocity) divided by peak systolic velocity. Normal renal resistive index less than 0.7; elevated resistive index (greater than 0.8) suggests vascular disease or parenchymal pathology.
Related Terms
- PSV
- EDV
- Doppler ultrasound
Key Points
- Resistive index elevated in renal artery stenosis (greater than 0.8), acute kidney injury, or chronic kidney disease; normal less than 0.7