FujiFilm SonoSite Edge II User Manual page 137

Pressure Gradient (PGr) in mmHG
Oh, J.K., J.B. Seward, A.J. Tajik. The Echo Manual. 2nd ed., Lippincott, Williams, and Wilkins, (1999), 64.
2
4 * (Velocity)
Peak E Pressure Gradient (E PG)
2
E PG = 4 * PE
Peak A Pressure Gradient (A PG)
A PG = 4 * PA2
Peak Pressure Gradient (PGmax)
PGmax = 4 * PV2
Mean Pressure Gradient (PGmean)
2
PGmean = 4 * Vmax
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
Measurement publications and terminology 131