General Calculation Formulas - GE Logiq 500 User Manual

General Calculation Formulas

Calc
Mnemonic Calc Name
MaxPG Maximum Pressure
Gradient
MeanPG Mean Pressure Gradient
SV Stroke Volume
CO Cardiac Output
FV Flow Volume
FVO Flow Volume Output
% Stenosis Stenosis Ratio
PI Pulsatility Index
RI Resistivity Index
HR Heart Rate (beats/minute)
A/B Ratio Velocities Ratio
TAMAX Time Averaged Maximum
Velocity (Trace Method is
Peak or manual)
TAMIN Time Averaged Minimum
Velocity (Trace method is
Floor)
TAMEAN Time Averaged Mean
Velocity (Trace method is
Mean)
TAMODE Time Averaged Mode
Velocity (Trace method is
Mode)
*NOTE*: V
diastole
Table 8–1. General Calculation Formulas
LOGIQ 500 Basic Users Manual
2233658–100 Rev. 0
Input Measurements
two Doppler blood flow peak
velocities
flow velocities from one time
marker to another time marker
in a Doppler display
flow velocities from one time
marker to another time marker
in a Doppler display and one
area
two distances and one 2 beat
time interval
flow velocities from one time
marker to another time marker
in a Doppler display and one
area
flow velocities from one time
marker to another time marker
in a Doppler display and one
area
two areas (by ellipse, trace,
circle or distance)
two Doppler blood flow peak
velocities and TAMAX
two Doppler blood flow peak
velocities
one 2 beat time interval
two Doppler blood flow peak
velocities
two time marks in a Doppler
display
two time marks in a Doppler
display
two time marks in a Doppler
display
two time marks in a Doppler
display
= V or V (depends on preset selection)
min end–diastole
General Calculations
Formula
MaxPG[mmHg]=4x(v1^2–v2^2)
MeanPG[mmHg]=
n
4x (Vi^2)/n
i=1
SV[ml]= (sum{V } from t1 to
t^2
t2)x a1
CO[1/min]=
SVxHR/1000
FV [ml] = (sum{Vt[m/s]} from
t1 to t2) x a1[cm^2]
FVO [ml/min] = FV [ml] /
(t2–t1) x 60000
% Stenosis= [1–(A /
residual
A )]x100
lumen
PI=(V –V )/TAMAX
max diastole
*NOTE*
RI=(V –V )/V
max diastole max
*NOTE*
HR[BPM]=120[sec]/
2beat time [sec]
A/B=V /V
1 2
TAMAX=sum{V } from t1 to
t
t2/(t2–t1) [cm/s or m/s]
TAMIN=sum{V } from t1 to
t
t2/(t2–t1) [cm/s or m/s]
TAMEAN=sum{V } from t1 to
t
t2/(t2–t1) [cm/s or m/s]
TAMODE=sum{V } from t1 to
t
t2/(t2–t1) [cm/s or m/s]
8–11