flow

Question 1

What does flow-dependent MRA capitalize on?
a. Artifactual appearances caused by ESP
b. TOF phenomenon
c. Phase shifts seen in the magnetic moments of spins moving along a gradient
d. All of the above

Answer 1

d. All of the above

Question 2

What is possibly the most important factor in determinng the degree to which entry-slice phenomenon (ESP)
penetrates into a stack of slices?
a. TR
b. Direction of flow
c. Slice thickness
d. Velocity of flow

Answer 2

b. Direction of flow

Question 3

When does entry-slice phenomenon increase?
a. At the first slice in the stack
b. When using a long TR in thin slices
c. When flow is in the opposite direction to slice excitation
d. All of the above

Answer 3

d. All of the above

Question 4

Regarding time-of-flight flow phenomenon, high-velocity signal void increase, which of the following is
INCORRECT?
a. TE decreases
b. Velocity of flow increases
c. Slice thickness decreases
d. TE increases

Answer 4

d. TE increases

Question 5

Which one of the four PRINCIPAL types of flow travels with greater velocity at the center of the lumen than at
the vessel wall, but the velocity difference across the vessel is constant?
a. laminar flow
b. turbulent flow
c. vortex flow
d. helical flow

Answer 5

a. laminar flow

Question 6

Which of the following is a DISADVANTAGE of inflow MRA (magnetic resonance angiography)?
a. high resolution for small vessels
b. sensitive to T1 effects
c. saturation of in-plane flow
d. 3D inflow MRA

Question 7

What does flow-dependent MRA capitalize on?
a. Artifactual appearances caused by ESP
b. TOF phenomenon
c. Phase shifts seen in the magnetic moments of spins moving along a gradient
d. All of the above

Answer 7

d. All of the above

Question 8

Which of the following has as its goal to totally nullify signal from flowing blood?
a. inflow MRA (magnetic resonance angiography)
b. phase-contrast MRA
c. black blood imaging
d. 2D sequential inflow angiograms

Answer 8

c. black blood imaging

Question 9

Which of the following is a remedy for flow motion artifact?
a. patient immobilization
b. gating/triggering
c. reduce FOV (field of view)
d. increase receive bandwidth

Answer 9

b. gating/triggering

Question 10

When flow velocity changes erratically across the vessel, it is ________.
a. Vortex flow
b. Spiral flow
c. Laminar flow
d. Turbulent flow

Answer 10

d. Turbulent flow