Resistance index in veins?

✍ Scribed by Nevbahar Akcar; I. Ragip Ozkan; Tamer Kaya; François Tranquart

• Book ID: 102332770
• Publisher: John Wiley and Sons
• Year: 2004
• Tongue: English
• Weight: 32 KB
• Volume: 32
• Category: Article
• ISSN: 0091-2751
• DOI: 10.1002/jcu.20048

✦ Synopsis

W e read with interest the manuscript ''Color Doppler Imaging of Orbital Vessels: Personal Experience and Literature Review'' by Transquart et al, 1 but we noticed that the authors were using the resistance index (RI) to describe the flow in the central retinal vein (page 264). It is well known that RI, which is calculated as (peak systolic velocity -end diastolic velocity)/peak systolic velocity, is a semiquantitative Doppler parameter that is used to evaluate arterial blood flow. 2-4 RI is a measure of downstream arterial resistance against blood flow, with the greatest contribution to resistance occurring at the arteriolar level. 2 RI should not be used for venous structures because in almost all of them the flow is steady, lacking systolic and diastolic components.