FujiFilm SonoSite SII, User Manual Supplement

Page: 44 / 476

42 Measurement references
Peak Pressure Gradient (PGmax)
PGmax = 4 * Vmax
2
Mean Pressure Gradient (PGmean)
PGmean = 4 * Vmax
2
(average pressure gradient during the flow period)
Pulsatility Index (PI)
Zwiebel, W. J., Introduction to Vascular Ultrasonography , 4th Edition, W.B. Saunders Company, (2000).
PI = (PSV – MDV)/V (no units)
where: PSV = peak systolic velocity
EDV = minimum diastolic velocity
V = TAP (Time Averaged Peak) flow velocity throughout the cardiac cycle
Resistive Index (RI)
Kurtz, A.B., W.D. Middleton. Ultrasound-the Requisites . Mosby Year Book, Inc., (1996), p.467.
RI = ((Velocity A – Velocity B)/Velocity A) in measurements
where: A = velocity
B = velocity cursor x
Time Averaged Mean (TAM) in cm/s
TAM = mean (mean Trace)
Time Averaged Peak (TAP) in cm/s
TAP = mean (peak Trace)
Volume Flow (VF) in ml/m
Robert J. Daigle, BA, RVT: Techniques in Noninvasive Vascular Diagnosis ; Second Edition, p.210
One of the following, depending on the Live Trace setting:
VF = CSA * TAM * 60
VF = CSA * TAP * 60
VF = CSA * TAV * 60 (When manual trace is used)