Doppler and Color Flow

Question 1

Flow Rate formula

Answer 1

Flow rate = area x velocity

Question 2

Volume formula

Answer 2

Volume = area x velocity time integral (VTI)

Question 3

Pressure gradient formula

Answer 3

PG = 4V^2

Question 4

Pressure Half Time formula

Answer 4

PHT = 0.29 x DT

Question 5

MVA formula

Answer 5

MVA = 220 / PHT

Question 6

PVR formula

Answer 6

PVR = TR velocity / RVOT VTI

Question 7

AVA continuity equation

Answer 7

AVA = LVOT area * LVOT VTI / AV VTI

Question 8

PISA ERO MR formula

Answer 8

ERO = 6.28 * radius^2 * aliasing velocity / MR velocity

Question 9

Doppler velocity formula

Answer 9

c (speed of US in blood) / 2 * change in frequency / transmitted frequency

Question 10

Pressure half time

Answer 10

Time required for initial pressure gradient to be reduced by half

Question 11

PHT in MS

Answer 11

Longer = worse

Mild = 100 ms
Mod = 200 ms
Severe = 300 ms

Question 12

PHT for MR in prosthetic valve with Peak velocity > 2

Answer 12

Severe MR or High output with PHT < 130 ms

Question 13

PHT in AR

Answer 13

Severe < 200 ms

Question 14

Nyquist limit

Answer 14

Limit of velocity that can be measured with PW

= PRF / 2

Question 15

Increase Nyquist limit

Answer 15

Shorten depth

Question 16

Stroke volume equation

Answer 16

SV = LVOT area x LVOT VTI

Question 17

Normal LVOT diameter

Answer 17

2.1-2.4 cm

Question 18

Normal LVOT area

Answer 18

3.46-4.5 cm2

Question 19

Normal LVOT velocity

Answer 19

0.9-1.1 m/s

Question 20

Normal LVOT VTI

Answer 20

18-24 cm

Question 21

Qp/Qs

Answer 21

(RVOT area x RVOT VTI) / (LVOT area x LVOT VTI)

Question 22

MR PISA

Answer 22

Flow at PISA = Flow at ERO

A x V of PISA = ERO x V of MR

Question 23

Systemic Flow in PDA

Answer 23

Across RVOT

Question 24

Pulmonary flow in PDA

Answer 24

Across LVOT

Question 25

Cross sectional area for flow

Answer 25

CSA = (1/2 x D)^2 * Pi

Question 26

PADP

Answer 26

(4 x end-diastolic velocity^2) + RAP