B-K Medical Pro Focus 2202, User Manual

Page: 223 / 356

General Pro Package 223
Table 15-6. Vascular calculation formulas.
Value Formula
Frequency Difference
Velocity Difference
Frequency Acceleration (FAcc)
Acceleration (Acc)
Resistance Index/Pourcelot Ratio
(RI)
TAM (Time Average Mean)
A/B Ratio (Stuart Index)
Pulsatility Index (PI)
Heart Rate (HR) per minute
Stenosis (Distance)
Stenosis (Area)
Volume Flow
dF F t
2
( )
F t
1
( )
– =
dV V t
2
( )
V t
1
( )
– =
F
acc
F
max
t
2
( )
F
max
t
1
( )
–
t
2
t
1
–
-------------------------------------------------- =
Acc
V
max
t
2
( )
V
max
t
1
( )
–
t
2
t
1
–
-------------------------------------------------------- =
RI
F
max
t
PS
( )
F
max
t
ED
( )
–
F
max
t
PS
( )
---------------------------------------------------------------- =
TAM
t d V
mean
t
) (
t t
1
=
t
2
∑
⋅
t
2
t
1
–
------------------------------------------- =
A
B
----
F
max
t
PS
( )
F
max
t
ED
( )
----------------------------- =
PI
t
ED
t
SS
–
( )
F
max
t
PS
) (
F
max
t
MD
) (
–
( ) ⋅
dt F
max
t
) (
t t
SS
=
t
ED
∑
⋅
------------------------------------------------------------------------------------------------- =
HR
Number of Cycles 60
×
t
ED
t
SS
–
-------------------------------------------------------- =
Stenosis dist
( )
D
1
D
2
–
( )
D
1
------------------------
100
×
=
Stenosis area
( )
A
1
A
2
–
( )
A
1
------------------------
100
×
=
VF TAM A
⋅
=