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Flashcards in MRI Physics 4 Deck (100)
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1

In which directions can PC MRA be flow sensitive
a. through plane
b. in plane
c. a and b
d. none of the above

c. a and b

2

Which of the following statements are true concerning venous flow imaging with bright blood TOF-MRA
I. slower than arterial flow
II. lower flow related enhancement than arterial flow
III. cannot be imaged with TOF

a. I only
b. I and II only
c. II and III only
d. I II and III

b. I and II only

3

If one desires to do a set of axial 2D-TOF MRA scans for the saphenous veins, where should sat pulses be placed in relation to the imaging region
a. inferior
b. superior
c. a and b
d. none of the above

b. superior

4

Pulsating motion is best described as
a. acceleration
b. stagnation
c. jerk
d. none of the above

c. jerk

5

Time of Flight (TOF) effects can lead to
a. MRI signal loss from flow
b. MRI signal gain from flow
c. a and b
d. none of the above

c. a and b

6

In order to make every slice and "entry slice", the slice excitation wave should be performed
a. co current
b. counter current
c. inferior to the FOV
d. superior to the FOV

b. counter current

7

Which of the following is not a mechanism for MRI signal loss in flow
a. turbulence
b. flow compensation
c. dephasing effects
d. none of the above - all cause signal loss

b. flow compensation

8

Which timing parameter is critical for "black blood" MRA
a. TR
b. TE
c. TI
d. none of the above

b. TE

9

The most common procedure for the Circle of Willis is _____, while the most common procedure for the carotids is _____.
a. 2D-TOF, 2D-TOF
b. 2D TOF, 3D TOF
c. 3D TOF, 2D TOF
d. 3D TOF, 3D TOF

c. 3D TOF, 2D TOF

10

Application of pre-sat pulses during a flow imaging sequence will ____ SAR and ____ the number of slices per TR period.
a. decrease, decrease
b. decrease, increase
c. increase, decrease
d. increase, increase

c. increase, decrease

11

The usual MRI picture displayed on the console is the
a. phase image
b. magnitude image
c. a and b
d. none of the above

b. magnitude image

12

If the slice thickness is increased, then high velocity signal loss in "black blood" TOF-MRA tends to
a. decrease
b. stay the same
c. increase
d. none of the above

a. decrease

13

Magnetization Transfer directly affects which spins
a. free water
b. fat
c. protein bound water
d. protein bound fat

c. protein bound water

14

Intra voxel dephasing occurs for which kind of flow
a. turbulent
b. laminar
c. a and b
d. none of the above

c. a and b

15

In PC MRA flow velocity is mapped into the
a. frequency
b. phase
c. a and b
d. none of the above

b. phase

16

For SE imaging of flow, odd echo dephasing will occur for which kind of flow
a. turbulent
b. laminar
c. a and b
d. none of the above

c a and b

17

Which of the following techniques will be useful for reducing intra voxel dephasing
I. increase voxel size
II. increase TE
III. use gradient moment nulling (GMN)

a. I only
b. I and II only
c. III only
d. I II and III

c. III only

18

Bends in the ICA can mimic stenosis in "bright blood" MRA because of
a. turbulent flow
b. vortex flow
c. plug flow
d. accelerated flow

d. accelerated flow

19

Even Echo Rephasing works for SE sequences with
a. symmetric echoes
b. asymmetric echoes
c. a and b
d. none of the above

a. symmetric echoes

20

If the following orders of gradient lobes are turned on for the same amount of time,which set of relative amplitudes will compensate for accelerated fluid motion
a. 1 neg, 1 pos
b. 1 pos, 2 neg, 1 pos
c. 1 neg, 3 pos, 3 neg, 1 pos
d. 1 neg, 3 pos, 1 neg, 3 pos

c. 1 neg, 3 pos, 3 neg, 1 pos

21

In order to image flow in the jugular veings using 2D TOF MRA slices should be acquired in what order
a. I to S
b. S to I
c. A to P,
d. P to A

a. I to S

22

If A0 is the vessel radius, r is the cylindrical radial coordinate, and V0 is a constant, then the laminar flow velocity V(r) is given by
a. V(r) = V0
b. V(r) = V0(1-(r/A0))
c. V(r) = V0(1-(r/A0)^2)
d. none of the above

c. V(r) = V0(1-(r/A0)^2)

23

Sensitivity to flow near the edge of a vessel could best be accomplished with ___, while flow near the lumen center is best determined with ______.
a. low VENC, low VENC
b. low VENC, high VENC
c. high VENC, low VENC
d. high VENC, high VENC

b. low VENC, high VENC

24

Shaded surface Display is
a. an RF artifact
b. an MRA display method
c. a and b
d. none of the above

b. an MRA display method

25

Using cardiac gating, which parameter is set by the patient heart rate
a. TR
b. TE
c. TI
d. a and c

a. TR

26

For "bright blood" MRA, which pulse sequence is more likely to be used.
a. Incoherent GRE
b. Coherent GRE
c. SE
d. EPI

a. incoherent GRE

27

The most common artifact associated with MOTSA is
a. ghosting
b. aliasing
c. venetian blind
d. all of the above

c. venetian blind

28

Which is the critical time parameter for flow related enhancement
a. TR
b. TE
c. TI
d. none of the above

a. TR

29

"Flow Encoding" in PC MRA refers to
a. readout
b. spoilers
c. reqinders
d. gradient sensitizing directions

d. gradient sensitizing directions

30

Which of the following effects reduce flow saturation in MRA scans
I. increasing the FA
II. decreasing TR
III. using gadolinium contrast

a. I and II only
b. I and III only
c. III only
d. I II and III

c III only