MUGA Flashcards
what quantitative data do we get from a MUGA?
- global and regional EF
- phase and amplitude (Fourier Analysis)
- stroke volume and paradox image
- peak filling/emptying rates
word to describe “less or diminished contraction” of wall motion
hypokinesis
word to describe “late contraction” of wall motion
tardokinesis
word to describe “out of phase with the rest” wall motion
dyskinesis
word to describe no wall motion
akinesis
how is stroke volume calculated?
SV = (ED volume - bkg) - (ES volume - bkg)
normal SV
~80-100 ml/beat
how is ejection fraction calculated?
((EDvol - bkg) - (ESvol - bkg)/(EDvol - bkg)) * 100
how is cardiac output calculated?
SV * HR
normal cardiac output
5-6L/min
normal EF
~50-80%
peak filling/emptying rates
reflection of early rapid filling phase of DIASTOLE and measures LV compliance (elasticity)
normal emptying/peak filling rate
> 2.5 EDV/sec
of frames needed to obtain reliable peak filling rate
> 32 frames
what is seen in an acquired MUGA image
liver/spleen
lungs
aorta and pulmonary arteries
what does pericardial effusions look like?
thicker lines between heart and liver (cold line)
best view for right atrium
ANT
LAO during vent systole
normal variant for right atrium
enlargement
best view for left atrium
LAO or LLAT
best view for right ventricle
LAO or ANT
if a patient has LBBB, what occurs in the ventricles?
out of sync contractions between R and L ventricles
enlargement of the right ventricle could mean…
pulmonary hypertension or cardiomyopathy
best view for L ventricle
LAO
normal LVEF
50-80% (at rest)
normal RVEF
40-60%
stress LVEF
+ 5-10%
SV = ?
EDV - ESV
phase
ex. LV and RV contracting at the same time, and oppo of artia contraction
amplitude
amount of contraction
stroke volume image
subtracting ES frame from the ED frame giving result to ring that represents stroke volume
ED-ES = SV
paradox image
subtracting ED from ES, being left with nothing unless paradoxical motion occurring
ES-ED
what are possible pathologies for an abnormal MUGA
- cardiotoxicity
- CAD/MI
- CHF (congestive heart failure)
- cardiomyopathy
what chemotherapy agents are linked to cardiotoxicity?
- anthracyclines (doxurubicin/adriamycin)
- trastuzumab (herceptin)
what baseline EF indicates high risk for cardiotoxicity?
<30%
mild cardiotoxicity
drop in EF <10%, EF >45%
moderate toxicity
drop in EF = 15%, EF <45%
severe toxicity
drop in EF = 20%, EF <30%
how will wall motion be effected by CAD?
area of ischemia or infarct in the area of wall motion abnormality with hypokinesis or akinesis on STRESS study
REST = no wall motion abnormality (unles infarct or very sig. ischemia)
CAD:
rest images
amp and phase normal unless severe CAD (>75%)
CAD:
stress images
phase - areas of hypokinesis or akinesis
amplitude - loss of contractility from ischemia
SV - void in ring in areas of hypo or akinesis
LV dysfunction (low EF or abnormal wall motion) + normal RV = ?
ischemia
bilateral ventricular enlargement and dysfunction = ?
inflammation
what can be an early sensitive indicator of CHF?
decrease in PFR
dilated cardiomyopathy
chambers of heart are enlarged
hypertrophic cardiomyopathy
myocardium thicken, so chambers are smaller
restrictive cardiomyopathy
change in compliance, resistance to filling, less stretchy
what can cause dilated cardiomyopathy?
CAD, viral/bacterial infection, chronic hormone disorders, alcohol, drugs, chemo, pregnancy, RA
what are the effects of dilated cardiomyopathy?
- valvular regurgitation
- decreased LVEF
- increased risk of clot formation (stagnation)
causes of hypertrophic cardiomyopathy
- unknown… possibly genetic
what are the effects of hypertrophic cardiomyopathy?
- fibrosed tissue
- LV dysfunction, decreased perf.
- eventual decrease SV, EF
- A Fib, mitral valve reguritation
appearance of dilated cardiomyopathy
dilation in all 4 chambers
decrease LVEF. RVEF. LV wall thickness
appearance of hypertrophic cardiomyopathy
normal or small LV cavity, normal or slightly elevated LVEF
appearance of restrictive cardiomyopathy
normal LV cavity, normal or decreased LVEF, normal or enlarged RV cavity and normal or decreased RVEF
true aneurysm
3 layers of heart wall
ant or anteroapical wall usually
aneurysm
weakening of wall
false/pseudo aneurysm
doesn’t involve endocardium
mitral or aortic regugitation
no increase in EF on stress MUGA
aortic stenosis
normal or elevated LVEF at rest, decline in EF during stress
(due to increased afterload pressures of stenosed valve)
tricuspid regurgitation
dilated RV and decreased RVEF
choice for assessment of valvular heart disease
doppler echocardiography
false positives
underestimates LVEF
including LA or aorta in ROI
increase/decrease LVEF?
decreases LVEF
subtracting too little background
increase/decrease LVEF?
decreases LVEF
subtracting too much background
increase/decrease LVEF?
increases LVEF
excluding part of LV in ROI
increase/decrease LVEF?
increases LVEF
