Doppler Review

Question 1

what’s the doppler equation

Answer 1

Delta f = 2 x f0 x V x cos % C

Question 2

advantages of PW doppler

Answer 2

• range specificity
• sample volume adjustment
• map velocities @ any point
• 2D display guidance

Question 3

disadvantages of PW doppler

Answer 3

• can’t measure high velocities
• aliasing
• limited by speed of sound and PRF

Question 4

advantages of CW doppler

Answer 4

• can pick up high velocity

Question 5

disadvantages of CW doppler

Answer 5

• no range resolution

- unable to be sure a velocity is coming from a specific location

Question 6

what is tissue doppler used for

Answer 6

• movement of myocardial tissue

Question 7

do TDI signals have a greater or smaller intensity?

Answer 7

greater

Question 8

advantages of PW tissue doppler

Answer 8

• easily reproducible
• provides systolic & diastolic info
• can be performed on TDS patients
• less volume (PRELOAD) dependent than MV inflow

Question 9

disadvantages of PW tissue doppler

Answer 9

• angle dependent

- e primes should be measured @ end expiration

Question 10

Spectral doppler settings

Answer 10

• baseline 1/4 from bottom or top
• waveform occupies at least 50%
• gain

Question 11

colour doppler advantages

Answer 11

• sensitive
• can display anatomic & hemodynamic info on one image
• able to detect laminar from turbulent

Question 12

disadvantages or colour doppler

Answer 12

• aliasing

- directional ambiguity (when blood flow is perpendicular to beam, multiple colours appear)

Question 13

what relationships does the bernoulli equation outline

Answer 13

• velocity and pressure

Question 14

in bernoulli equation, if velocity increases, what happens to pressure?

Answer 14

decreases

Question 15

state the bernoulli equation

Answer 15

P1-P2 = 4 (v) squared

Question 16

what do we used the bernoulli equation to assess?

Answer 16

• max instantaneous and mean pressure gradients

Question 17

how many beats do you measure when arrhythmias are present?

Answer 17

3-5

Question 18

what is the continuity equation or stroke volume?

Answer 18

SV = 0.785 (D*2)(VTI)

Question 19

T/F - in a normal heart where there is no significant regurgitation or shunts, the SV through all four valves will be the same?

Answer 19

true

Question 20

what is Dp/Dt

Answer 20

change in pressure over time