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Chapter 8 Flashcards

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1
Q

When using MRA to evaluate intracranial vascularity, flow within smaller vessels can best be demonstrated by:

A

3D Time of Flight MRA

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2
Q

What determines the length of the R to R interval?

A

The patient’s heart rate

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3
Q

If the R to R interval is 500 ms, the trigger window is 10%, and the trigger delay is 50 ms, what is the time available to acquire data?

A

400 ms

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4
Q

What is the waiting period after each R wave called?

A

Trigger Delay

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5
Q

Which of the following best describes what the “P” wave represents?

A

Atrial Systole (Contraction)

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6
Q

What is the available imaging time using these parameters? R to R 800 ms, trigger window 10%, delay after trigger 4 ms.

A

716 ms

800- 80 - 4 = 716 ms

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7
Q

The vascular signal, produced on PC-MRA, relies on:

A

Velocity-induced phase shifts

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8
Q

How much does a typical patient’s heart rate vary during an exam?

A

10- 20 %

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9
Q

The vascular signal, produced on time of flight MRA (TOF-MRA), relies on:

A

Flow related enhancement

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10
Q

Which of the following does NOT reduce flow motion artifact?

A

Subtraction

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11
Q

Which of the following best describes what the “QRS” complex represents?

A

Ventricular Systole

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12
Q

Generally, 3D TOF-MRA acquisitions are optimal for high resolution, for the evaluation of:

A

Smaller vessels with high velocity blood flow (intracranial vessels associated with the Circle of Willis, COW)

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13
Q

The signal from flowing blood within vessels in MRI and MRA relies on:

A

First order motion

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14
Q

In spin echo sequences using a pre-saturation pulse, what would persistent bright signal within the vessel indicate?

A

Vascular Occlusion
Blood Clot
Slow Flowing Blood

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15
Q

What is the waiting period before each R wave called?

A

Trigger Window

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16
Q

Which of the following sequence(s)/techniques(s) can be used to produce images where vessels appear dark?

A

The Application of Pre-Sat Pulses

Spin Echo Acquisitions

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17
Q

When using MRA to evaluate extracranial vascular flow, such as that within common carotid arteries, a recommended technique is:

A

2D time of flight MRA

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18
Q

Which of the following best describes what the “T” wave represents?

A

Ventricular Diastole (Relaxation)

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19
Q

Which of the following is used to trigger each pulse sequence when using ECG gating?

A

R wave

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20
Q

ECG gating is prospective. (T or F)

A

true

Prospective- the scan is time to and triggered from the beats of the heart during acquisition

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21
Q

Multiphase images, acquired with additional modulation of magnetization, are known as:

A

SPAMM

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22
Q

Contrast enhanced MRAs are acquired with all of the following EXCEPT:

A

VENC settings

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23
Q

Which of the following sequence(s)/technique(s) can be used to make vessels appear bright?

A

Contrast Enhancement
Gradient Moment Rephasing
Gradient Echo Imaging
(all of the above)

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24
Q

Which of the following can be used to improve coverage and at the same time maintain the signal from blood flowing within the larger volume?

A

MOTSA

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25
Q

MRA techniques include all of the following EXCEPT:

A

CT-MRA

26
Q

When using MRA to evaluate peripheral vascular flow, such as that within the arteries of the legs, saturation pulses are:

A

Placed inferior to the acquired slices

Saturation pulses can be used to suppress the signal from venous blood to allow for better visualization of arterial flow.

27
Q

How much do most patient’s heart rate vary during the scan?

A

10-20%

28
Q

What position in the chest does the heart lie?

A

double oblique

29
Q

where is base of heart

A

located superiorally

30
Q

where is apex of heart

A

located inferiorally

31
Q

where is atrial septum

A

separates atria

32
Q

where is ventricular septum

A

separates ventricles

33
Q

prospective gating

A

scan is triggered from beats of heart, uses R-R

34
Q

retrospective gating

A

after scan is completed

35
Q

MOTSA

A

maintain signal and improve coverage w large volume

36
Q

MIP

A

projects maximum intensity

37
Q

SSD

A

surface is presented on the reformated data as though illiminated by directional light source

38
Q

SPAMM

A

spatial modulation of magnet

39
Q

3D TOF MRA

A

high resolution, evaluation of smaller vessles w high velocity blood flow (COW)

40
Q

2D TOF MRA

A

slow velocity w large FOV (carotids, venous)

41
Q

vessel appearance spin echo with pre-saturation

A

black blood

42
Q

vessel appearance gradient echo with GMN

A

bright blood

43
Q

vessel appearance peristant signal within a vessel lumen after the application of a SAT pulses

A

slow flow. Ex (blood clot or vascular occlusion

44
Q

parameters used in gating : T1 weighting

A

1 R-R interval, short TE

45
Q

parameters used in gating : PD weighting

A

2-3 R-R intervals, short TE

46
Q

parameters used in gating : T2 weighting

A

2-3 R-R intervals, long TE

47
Q

What is the equation for available imaging time?

A

=R-R interval - (trigger window + trigger delay)

48
Q

Which are options for the optimization of scan timing

A

bolus tracking: tracker pulse measures signal from the lumen

fluoro triggering: the operator witnesses the arrival of the contrast

test bolus: small injection made to determine the exact time to begin scanning

49
Q

trigger window

A

waiting time before each R-R wave

50
Q

trigger delay

A

waiting period after each R-R wave

51
Q

Digital Subtraction MRA

A

2 T2 data sets, one during systolic and one during diastolic (fresh blood imaging)

52
Q

TOF MRA

A

enhancment related to the flow of blood

53
Q

PC MRA

A

signal relies on velocity-induced phase shifts

54
Q

contrast enhanced MRA

A

T1 3D gradient echo following by gad and dynamic imaging

55
Q

Which of the following statements concerning the safety of gating is correct?

A

Do not used frayed or splitting cables
Do not loop or cross-over cables
Make sure the cables do not touch the patient
Place pads between the cables and the patient

56
Q

Calculate the correct dosage of gadolinium contrast for a 160-pound patient with normal renal function.

A

15 mL

165/2.2=75kg*0.2=15mL

57
Q

ECG

A

electrodes and wires placed on pts chest

58
Q

peripheral gating

A

placed on pts finger

59
Q

black blood

A

SE w pre-sats, inversion recovery

60
Q

bright blood

A

GRE, GMN, contrast enhancement

Physics (15 decks)

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