User guide

Chapter 5: Measurement References 87
References
Pulsatility Index (PI)
Kurtz, A.B., W.D. Middleton. Ultrasound-the
Requisites
. Mosby Year Book, Inc., (1996), 469.
PI = (PSV – EDV)/V
where PSV = peak systolic velocity
EDV = end diastolic velocity
V = mean flow velocity throughout
the entire cardiac cycle
Resistive Index (RI)
Kurtz, A.B., W.D. Middleton. Ultrasound-the
Requisites
. Mosby Year Book, Inc., (1996), 467.
RI = abs ((Velocity A – Velocity B)/Velocity A) in
measurements
where A = velocity cursor +
B = velocity cursor x
Time Averaged Mean (TAM) in cm/s
TAM = mean (mean Trace)
Time Averaged Peak (TAP) in cm/s
TAP = peak (peak Trace)
Volume (Vol)
Beyer, W.H. Standard Mathematical Tables , 28th
ed., CRC Press, Boca Raton, FL, (1987), 131.
Volume Flow (VF) in ml/m
Allan, Paul L. et al. Clinical Doppler Ultrasound , 4th
ed., Harcourt Publishers Limited. (2000), 36-38.
One of the following, depending on the Live Trace
setting:
VF = CSA * TAM * .06
VF = CSA * TAP * .06