Ch 9 Flow + Doppler Effect

Question 1

Where would we see pulsatile flow?

Answer 1

-Heart
-Arteries

Question 2

What 3 things does pulsatile flow depend on?

Answer 2

-Resistance
-Inertia of fluid
-Compliance

Question 3

What can we measure with the doppler effect?

Answer 3

-Presence of blood flow
-Direction of blood flow
-Speed of blow
-Character of flow (laminar vs turbulent)
-Presence, direction + speed of tissue motion

Question 4

What is power doppler for?

Answer 4

-Detects amplitude of returning RBC signals
-Importance is to detect the presence of RBCs
-Used in very small vessels + slow flow

Question 5

Can we detect speed + direction of blood flow with power doppler?

Answer 5

Nope

Question 6

What is TDI used for?

Answer 6

-To measure myocardial velocity + direction in cardiac imaging
-To assess diastolic + systolic function of heart

Question 7

What 2 things is the doppler shift proportional to?

Answer 7

-Blood flow speed (velocity)
-Operating frequency

Question 8

What would be the estimated velocity if the doppler angle is 0, 60 + 85 degrees?

Answer 8

0: very accurate (is parallel)
60: we want our angle to be 60 degrees or less
85: we are overestimating the velocity

Question 9

Doppler angles should not exceed what degree?

Answer 9

Must be less than 60!!!

Question 10

What happens if we can’t align our doppler beam to be parallel to flow?

Answer 10

Use angle correct, line up the arrow so it is parallel with the vessel flow

(ex. in vascular imaging)