The resistive index (RI) is a Doppler ultrasound measurement used in vascular studies to assess downstream vascular resistance. It quantifies the pulsatility of blood flow, calculated as (peak systolic velocity – end-diastolic velocity) / peak systolic velocity. A higher RI value indicates increased resistance, which can signify conditions like arterial stenosis or downstream obstruction, impacting diagnostic accuracy in medical imaging.
Understanding the resistive index is crucial for clinicians evaluating various vascular pathologies. This non-invasive ultrasound parameter helps differentiate normal blood flow patterns from abnormal ones, aiding in the diagnosis and management of diseases affecting organs such as the kidneys, liver, and cerebral vasculature. Optimize your vascular ultrasound interpretations with a thorough grasp of RI values.