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98 Cards in this Set
- Front
- Back
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pacemaker of the heart
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SA node
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Depolarization
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heart contracts
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Recovery of heart called
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Repolarization
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which wave is atrial depolarizatoin
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P wave
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Which wave is ventricular repolarization
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t wave
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Which wave is ventricular depolarization
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QRS
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each block on EKG paper repersents ? seconds
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0.04 seconds
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most popular treadmill stress test protocol in North America
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Bruce
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a 24hr Tl delay scan done for ?
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Viability
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3 images for MPI
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Ant, 45 degree LAO, L lat
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A false positive septal defect frm treadmill testing is associated with?
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Left bundle branch block
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Undesirable images from tomographic reconstruction via backprojection is ?
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Star artifact
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Reconstruction method that is most common?
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Backprojection
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Sagittal cut is what view (3 letters)
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VLA
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Transverse cut is what view (3 letters)
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HLA
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Coronal cut is what view (2 letters)
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SA
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Which body position is used to reduce attenuation artifacts by breast or gut
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Decubitus
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a single horizontal profile of SPECT to detect motion
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Sinogram
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What % of Tl goes to the heart?
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3-5%
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Is Tl active or passive localization
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Active
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Which are RP is a K analog?
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Tl
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Which RP is best to test viability?
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Tl
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Tc-RP's are taken up actively or passively?
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Passive
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Which RP redistributes?
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Tl
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2 chemical classes of Tc?
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isonitriles- Sestamibi
diphosphones- Tetrofosmin |
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Defect seen in stress, but fill in during rest
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Ischemia
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Reversible blood perfusion loss
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Ischemia
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Myocardial Infarct
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Heart muscle permamnently scarred, non reversible
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what % stenosis will reduce blood flow during stress test? How much to see defect at rest?
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50%.
90% |
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Cardiolite also called?
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Sestamibi or MIBI
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How is Tc localized?
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hepatobiliary system, that's why we sait so long
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Another name for Myoview? This does or does not remain fixed in myocardium?
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tetrofosmin
does remain fixed |
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85% HR max calculation
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220-age= x times .85
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3 pharmacological stress drugs
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adenosine
dipyridamole dobutamine |
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If pt is not stressed to 85% max HR what can happen?
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Cannot rule out ischemia
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Why not do treadmill test? 2 reasons
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pt cant perform exercise
heart med limit HR |
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2 heart meds that limit HR
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Beta blockers
Ca channel blockers |
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Adenosine:
direct/indirect vasodilator Biologic T1/2 infusion time dose max vasodilation time |
Direct
T1/2=15 sec Inf time= 4 min 140ug/kg/min max=60s |
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contraindications for Adenosine
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Caffiene
Xanthine meds (theo/aminophylline) |
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Dypridamole
AKA direct/indirect vasodilator T1/2 injection time dose reversal med |
AKA- persantine
indirect vasodilator T1/2- 20min Injection time-4min dose- 0.56mg/kg med- animophylline |
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Dobutamine
T1/2 reason it's used |
T1/2- 2 min
use- COPD |
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reduced perfusion on R/S
reduced contractility called? |
hibernating myocardium
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artery is reopened. Perfusion improved, but reduced onctractility called?
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Stunned myocardium
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Greater deficit of blood flow on rest than stress? 2 names for it
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Reverse redistribution or excessive washout
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Enlarged heart known as and it seen more common on which ventricle?
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Myocardial hypertrophy
Left ventricle |
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Right ventricle activity normal is it is (greater, less) than left ventricle
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Less than left
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Lung:Heart ratio only done with which RP?
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Tl
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Greater than 35% lung:heart ratio indicates?
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LV dysfunction
Multi-vessel disease |
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What % of CABG are occluded after 1 year/ by 10 years?
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10-20% at 1 year;
50% at 10 years |
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Can an MPI be ordered because of an abnormal EKG?
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Yes
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4 MPI procedures
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1 day Tl
1 day Tc 2 day Tc Dual isotope |
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Pt prep for all MPI procedures
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stop ca channel & beta blockers
stop nitro drip NPO |
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NPO time for exercise MPI?Caffiene stop for exercise/drug test?
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4-6h
4-6h/24h |
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Doses for 1 day Tl
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4mci
3mci @ stress/ 1mCi @ rest |
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Why do you not need to reinject for Tl?
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Redistribution properties
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If you image before 10min (w/Tl) heart is seen 1" higher on stress than rest. This is called?
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Cadiac creep
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1 day Tc dose stress/rest
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20-30mCi stress
10mci rest |
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2 day Tc doses
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30mci stress
30mci rest @24h |
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In dual isotope which is the rest RP?
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Tl
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Doses for Tl and Tc for dual isotope
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4mci Tl-rest
30mCi Tc-stress |
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Why use SPECT instead of planar?
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Higher sensitive and specificity
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Coronal =? axis
Sagittal= ? axis Transvers= ? axis |
short
verticle horizontal |
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how does heart sit in body?
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points down, left and anterior
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4 walls of the heart
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Anterior
lateral inferior septal |
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How many views must a defect be seen on to verify a defect?
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2
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3 main arteries in heart
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Left ant descending (LAD)
Left circumflex (LCx) ;eft coronary artery (LCA) |
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Determines patency of myocardium; heart is opened up and flattened out
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Bull's Eye
or Polor map |
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On a polar map what part of the heart is the outside ring?
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Base
(defects here tend to be overemphasized) |
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Which RP can be used with gating and why?
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Tc- because Tl doesn't provide enough counts
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stress images are synchronized to EKG cycle
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Gating
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Gating frames/cycle for:
MUGA MPI |
MUGA: 8-16 frames/cycle
MPI: 16-32 frames/cycle |
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Amount of blood pumped out in one cycle is?
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Ejection fraction
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Amount of blood pumped out by LV in 1 minute?
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cardiac output
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Amount of blood pumped by a single beat?
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Stroke volume
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Diastolic is ?
systolic? |
relaxation
contraction |
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What EF is considered normal for MPI?
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greater than 50%
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Gating uses what kind of trigger?
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R wave trigger
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T or F? The septal wall is usually shorter than the lateral wall
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True
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2 ways cardiac function can be imaged without MPI?
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First pass
Equilibrium (MUGA) |
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First pass bolus RP's?
(if MUGA?) dose |
Bolus Tc-SC or Tc-DTPA
(if MUGA Tc PYP/RBC's) 10mCi |
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First pass ventriculogram body position/camera angle?
Time to complete? |
Supine/30 degree RAO
60 seconds |
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What info is taken from First pass?
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Wall motion
EF, Ejection rate, cardiac output, stroke volume, end diastolic/systolic volume |
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Dose of Tc-PYP/RBC's for MUGA?
Wait time? |
20mCi,
wait 20 minutes |
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Is MUGA a gated study?
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Yes
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3 vies for MUGA
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ANT, 45 LAO, 70 LAO
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Which angle shows best seperation of ventricles?
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45 degree LAO
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RP used in myocardial infarct avid imaging? Dose
Why do this? |
Tc-PYP 10-20mCi
taken up by dead tissue-shows bright in infarcted tissue |
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Best time frame to image infarct?
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1-3 days post MI
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Infarct images taken
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ANT/RAO/LAO/ L lat
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Positive MI scan grades
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0- normal study
1- heart act < ribs 2- heart activity = ribs 3- heart act. > ribs |
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0.56mg/kg which drug uses this?
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Dipryridamole
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T 1/2 Adenosine
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15 sec
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Infusion rate Adenosine
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4 minutes
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Dose Adenosine
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140ug/kg
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Dipryridamole T1/2
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20 min
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Dipryridamole injection time
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4 minutes
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Dobutamine T 1/2
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2 minutes
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Dose of dobutamine?
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5ug/kg/min forst 3 minutes
increase 5 ug every 3 minutes until target HR |
