FujiFilm SonoSite Edge II User Manual page 147

Pressure Gradient (PGr) in mmHG
Oh, J.K., J.B. Seward, A.J. Tajik. The Echo Manual
2
PG = 4 * (Velocity)
Peak E Pressure Gradient (E PG)
2
E PG = 4 * PE
Peak A Pressure Gradient (A PG)
2
A PG = 4 * PA
Peak Pressure Gradient (PGmax)
PGmax = 4 * Vmax
Mean Pressure Gradient (PGmean)
PGmean = 4 * Vmax
Pulsatility Index (PI)
Kurtz, A.B., W.D. Middleton. Ultrasound-the Requisites. Mosby Year Book, Inc., (1996), p.469.
PI = (PSV – EDV)/V
where:
PSV = peak systolic velocity
EDV = end diastolic velocity
V = mean flow velocity throughout the entire cardiac cycle
Zwiebel, W. J. Introduction to Vascular Ultrasonography
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 cursor +
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)
Measurement references
(velocity units must be meters/second)
2
2
(average pressure gradient during the flow period)
2nd ed., Lippincott, Williams, and Wilkins, (1999), p.64.
.
6th Edition, W.B. Saunders Company, 2012.
,
6-21