Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

NMED 251 - Clinical Procedures > MUGA > Flashcards

MUGA Flashcards

1
Q

What happens if a patient has a longer than average cardiac cycle?

A

Framing stops before end diastole which under represents EDV which decreases EF

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

What happens if a patient has a shorter than average cardiac cycle?

A

Lack of data to be recorded in the last few frames also resulting in a decrease of EDV = decrease EF

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

Too much background subtraction: effect on EF?

A

falsely increased EF = false negative results

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

Too little background subtraction: effect on EF?

A

falsely decreased EF = false positive results

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

what happens to the EF if LA overlaps LV ROI slightly?

A

overestimate ES which means more vol. at ES which means heart not doing a good job at contracting = underestimate EF

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

what are some artifacts seen in MUGAs?

A
  • arrhythmias
  • improper ROI
  • attenuation from ECG leads, pacemakers, other metals in FOV
  • poorly tagged RBCs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what are the advantages to MUGA?

A
  • accurate + non-invasive
  • reproducible
  • simple technique
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what are the disadvantages to MUGA?

A
  • RVEF can’t be accurately calculated
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what study is best to assess RVEF?

A

first pass

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

why is it difficult for us to assess RVEF?

A

RV can’t be easily separated from RA or an enlarged LV

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

what are the advantages to a gated equilibrium stress study?

A
  • more sensitive to ischemic changes
  • completed in short time period
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what are the disadvantages to a gated equilibrium stress study?

A
  • “demanding”
  • requires considerable patient compliance
  • more patient motion, less statistics/shorter images
  • more electrical interference on ECG
  • must have qualified physician present during stress
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

downfall of echocardiography? pros?

A

-no reproducibility
+noninvasive + accurate at determining EF

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

downfall of angiography? pros?

A

-invasive+high radiation dose
+highly accurate

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

downfall of gated MRI?

A

-demanding + requires multiple breath holds

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

downfall of gated CT?

A

-single breath holds + needs contrast injection

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

T/F
The purpose of tin when labeling RBC’s is to ensure 99mTc04- is reduced intracellularly.

A

true

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

T/F
When performing an LAO view, 5-10 degrees caudal tilt improves separation between the two ventricles.

A

False
separates LV and LA

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

T/F
A 3 lead ECG is adequate for gating MUGA studies

A

true

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

T/F
500 accepted beats per image provides adequate statistics

A

true

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

what is the range for beats per image in a MUGA?

A

300-600

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

what is the set time for a MUGA?

A

10 minutes

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

what are the counts needed for a MUGA?

A

3-5M

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

T/F
Wall motion that is described as dyskinetic means that the area of myocardium is not contracting as vigorously as expected.

A

false
dyskinetic describes phasing therefore, it would mean that the area is not in phase with what it is supposed to be in phase with (eg. ventricles)

hypokinetic is the proper term

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
p wave
atrial contraction
26
on an ECG, which wave indicates ventricular depolarization? repolarization?
QRS - R wave signals for ventricles to contract depolarization - t wave
27
indications for a MUGA
- baseline and follow up measurements for Sx or chemotherapy - assessing valvular heart disease, cardiomyopathies - eval EF, global and LV regional wall motion, size and volumes - CAD eval + post MI eval
28
how is EF calculated?
EF = (EDV-ESV)/(EDV)
29
what are contraindications for MUGA?
severe arrhythmias (atrial fibrillation, greater than 10% PVCs)
30
dose for MUGA study
740-1850 MBq
31
radiopharm used for MUGA
99mTc-RBCs IV infusion
32
critical organ of 99mTc-RBCs
Spleen
33
dosimetry in spleen?
1.1 mGy/37 MBq
34
excretion of 99mTc-RBCs
predominantly renal (25% in first 24hrs)
35
breastfeeding guidelines for 99mTc-RBCs (in vivo vs in vitro)
- stop 12 hours if done in vivo - in vitro = halt feeding for minimum of 4 hrs (pump and discard)
36
Which of the following is NOT an indication for a gated equilibrium study? A) Assess blood flow to the heart muscle B) Screening prior to or after chemotherapy C) Evaluation of cardiac chamber size D) Evaluation of the percentage of blood pumped from the heart/beat
A
37
how do we acquire data for MUGA?
dynamic frame mode that is triggered by R-R intervals
38
frame mode acquisition
data from each cardiac cycle has counts added to each frame until adequate counts are achieved or an average beat is obtained
39
what % is typical beat rejection?
+/- 10% to 20%
40
longer than average cardiac cycle = ?
framing to stop before end diastole - under represents EDV therefore decreases EF
41
shorter than average cardiac cycle?
lack of data recorded in last few frames = decreases EF
42
patients with infants?
limit contact to <5 hours for the first 24 hrs
43
how many frames do we choose per cycle?
16-32 frames
44
heart should occupy __% of FOV
50%
45
how long do we wait for homogeneous mixing? what does it mean?
10 minutes mixing with the rest of our blood around the body/heart evenly
46
what angles do we get images from for a MUGA?
ANT, LAO (30-60d) and LLAT caudal tilt (10-15d)
47
what other angles can be done?
LPO, RAO, RLAT
48
why do we do caudal tilts?
separation of LA/LV
49
what is best separation?
clearly see separation of right/left ventricles
50
what are some stop conditions?
- 10 min/image - 200-250 kcts/frame - 300-600 heart beats - 3-7M total counts
51
why do quantitative blood pool spect?
- isolates r/l ventricles without overlap therefore able to assess LVEF and RVEF - less time to acquire - better regional wall motion assessment
52
views for blood pool spect?
90 degrees - one detector doing 45d RAO - other at 45 LPO
53
T/F Setting up a MUGA acquisition with 32 frames will have greater temporal resolution than an acquisition with 16 frames.
true
54
smoothing spatial
each surrounding pixel around an individual pixel is examined and counts are averages
55
smoothing temporal
counts in pixel frame before and after area averaged
56
best septal view
LAO
57
where do we draw background ROI?
between 3 and 6 o'clock of LV
58
what is produced from ROIs?
time activity curve
59
qualitative analysis
visual - cine loop: for wall motion, ventricular size + wall thickness
60
quantitative analysis
time-activity curves, global ejection fraction, regional EF, phase + amplitude
61
hypokinetic
wall motion - not moving as much
62
akinetic
wall motion - not moving at all
63
dyskinetic aka?
paradoxical wall motion - moving the wrong way
64
normal LVEF?
50-80%
65
normal RVEF?
40-60%
66
time-activity curve
time of blood volume (aka counts) changes in LV during average cardiac cycle
67
how do we get a time activity curve?
by drawing ROI around the LV on every frame and the counts are then plotted on a graph over time
68
what can be derived from a time activity curve?
EF, peak ejection rate and peak filling rate
69
end frame drop off
caused by heart rate variability the EDV is not the same as it was in the beginning
70
normal stroke volume?
80-100ml
71
how do you calculation stroke volume?
EDV-ESV
72
normal cardiac output?
5-6L
73
how do you calculate cardiac output?
stroke volume * heart rate
74
normal EDV?
150ml
75
phase
comparing the timing of atrial and ventricular contraction
76
atria and ventricles should be contracting with the phase difference of ____
"180 degrees apart"
77
phases can be looked at by?
images and histograms
78
amplitude
degree/force of contraction - looking at regional wall motion
79
what area of the heart normally shows the least amount of contraction?
septal area
80
what areas show less contractility than healthy myocardium?
areas of old infarcts and scarring
81
what words are used to describe phase?
dissynchronous/synchronous dyskinetic/paradoxical
82
what words are used to describe amplitude?
hypokinetic/akinetic
83
_____ of the LV shows most movement _____ of the LV shows the least movement
most - lateral wall least - interventricular septum
84
for normal results, the septum ______ and moves slightly towards _____ during _____
septum shortens/thickens and moves slightly towards LV during systole
85
during a gated equilibrium stress study, what are normal results?
- increasing HR - minimum 5% increase in EF at max exercise - normal wall motion
86
what view(s) are acquired for an exercise MUGA?
LAO - multiple, resting and at each stage of exercise

NMED 251 - Clinical Procedures (11 decks)

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