Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

331 - imaging production > chap 8 > Flashcards

chap 8 Flashcards

(61 cards)

Start Studying
1
Q

MRA techniques include

A
  • PC- MRA
  • TOF - MRA
  • CE - MRA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is the equation for available imaging time ?

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

the parameters used in gating for T1 weighting

A

1 R-R interval, short TE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

the parameters used in gating for PD weighting

A

2-3 R-R intervals, short TE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

parameters used in gating for T2 weighting

A

2-3 R-R intervals, long TE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

the vascular signal, produced on PC-MRA, relies on

A

velocity - induced phase shifts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

remedy for Moire artifact

A

keep arms/shoulders or other anatomy within the FOV, use SE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

remedy for Magic angle artifact

A

move the body part or change the TE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

remedy for aliasing or “wrap” artifact

A

use “no phase wrap” software or increase the FOV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

remedy for chemical misregistration artifact

A

select a TE that matches the periodicity of fat and water, & use an SE rather than a GRE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

remedy for zipper artifact

A

check for RF leak, call an engineer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

remedy for cross excitation artifact

A

gap between the slices, alternate slices

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

remedy for chemical shift

A

use lower field strengths, smaller FOV, & lower rBW

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

remedy for truncation artifact

A

increase the number of phase encoding steps and not undersampling of data. Square matrix will also avoid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

remedy for Magnetic susceptibility

A

remove metal, use SE, decrease TE, lower field strengths

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

remedy for ghosting artifact

A

swap phase & frequency, pre sat, respiratory compensation, concise patient directions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

technique for black blood imaging

A

SE with pre sats, inversion recovery

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

technique for bright blood imaging

A

GRE, GMN, contrast enhancement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

how much do patients heart rate vary during the scan?

A

10-20%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what causes ghosting artifact

A

anatomy moving along the phase direction during the pulse sequence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what causes aliasing artifact

A

anatomy outside the FOV is mapped inside the FOV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what causes chemical shift artifact

A

different chemical environments of fat & water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what causes truncation artifact

A

under sampling of data

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what causes cross excitation artifact

A

RF pulse not square, adjacent slices get energy pulse from neighbors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
what causes a zipper artifact
leak in the RF shielding
26
what causes magic angle artifact
collagen or other tightly bound structure of fibers is 55 degree angle to Bo
27
what causes shading artifact
inhomogeneities in the main magnetic field
28
MRA techniques: 2 T2 data sets, one during systolic and one during diastolic (fresh blood imaging)
digital subtraction MRA
29
MRA techniques: Enhancement related to the flow of blood
TOF MRA
30
MRA techniques: Signal relies on velocity induced phase shifts , takes advantage that flowing nuclei moving along a bipolar gradient have a higher signal than stationary nuclei
PC MRA
31
MRA techniques: T1 3D gradient echo following gadolinium and dynamic imaging
contrast enhanced MRA
32
when using MRA to evaluate extracranial vascular flow, such as that within common carotid arteries, a recommended technique is
2D time of flight MRA
33
lead wires on the patients chest, used when imaging the chest, heart, & great vessels
ECK, EKG
34
light sensor attached to patients finger to detect pulses through capillaries, not as accurate
peripheral gating
35
bellows around the chest, signal corresponds to max and min motion of the chest, TR may be reduced
respiratory compensation
36
the signal from flowing blood within the vessels in MRI and MRA relies on
first order motion
37
scan is triggered from beats of the heart, uses R-R, signal during diastole
prospective gating
38
post process after the scan is completed, continuously throughout all the cardiac phases
retrospective gating
39
waiting time before each R-R wave
trigger window
40
waiting period after each R-R
trigger delay
41
MOTSA
maintain signal & improve coverage with large volume
42
projects maximum intensity
MIP
43
surface is presented on the reformatted data as though illuminated by a directional light source
SSD
44
the direction in which ghosting & truncation artifacts happen in
phase only
45
the direction in which aliasing, magnetic susceptibility, & magic angle artifacts happen in
both phase & frequency
46
the direction in which chemical shift & zipper artifacts happen in
frequency only
47
first small wave on ekg
p wave , atrial systole
48
last wave on ekg
T-wave , ventricular diastole, may be elevated due to magnetohemodynamic effect
49
chemical shift occurs in what direction
frequency only
50
the appearance of phase mismapping artifact (ghosting)
produces replications of moving anatomy across the image
51
the appearance of chemical shift artifact
dark edges at edge between fat & water
52
appearance of magnetic susceptibility artifact
large signal voids , worse on 3T than 1.5T
53
appearance of cross excitation & cross talk artifact
black line over cord, adjacent slices in different image contrasts
54
appearance of zipper artifact
dense line across the image
55
in tissues that contain collagen at high signal intensity
magic angle artifact
56
aka wrap, anatomy outside FOV is folded on top of anatomy inside FOV
aliasing
57
black & white bending at the edge of the FOV
Moire artifact
58
aka gibbs , from under sampling, banding at the interfaces of high & low signal, low intensity band running through high intensity area
truncation artifact
59
optimizes scan time - the operator witnesses the arrival of the contrast
fluoro triggering
60
optimizes scan time - tracker pulse measures signal from the lumen
bolus tracking
61
optimizes scan time - small injection made to determine the exact time to begin scanning
test bolus

331 - imaging production (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions