Intro to Non-invasive Cardiac Imaging Flashcards
Gold standard for evaluating CAD
coronary angiography
Types of exercise stress testing
Treadmill exercise test & bicycle ergometry
Parts of the myocardial ischemia cascade
perfusion abnormalities -> diastolic dysfunction -> systolic dysfunction -> ECG changes -> angina
Whys is coronary angiography not ideal for screening despite being the gold standard for evaluating CAD?
Due to exposure to radiation and contrast materials, which may
be toxic to some patients. It is an invasive assessment tool.
Computation for maximum HR?
220-age
Findings of exercise stress testing (hints: EJKs, Blackpink, you’re so FC, Ari, fly high)
EKG ischemic changes, BP responses, functional capacity, arrhythmia, high risk variables
Indications for Pharmacologic Stress Testing
1) Inability to exercise (3)
2) Limited exercise capacity (2)
3) Specific ECG findings (3)
1) physical limitations, recent operations, comorbidities
2) deconditioning/poor motivation, limiting physical conditions (COPD, claudication)
3) LV, CLBBB, pacemaker rhythm
Resting ECG findings which can give false positive pharmacological stress test: (hints: VH, excited, RBB, sad ST, fingers, pacing)
ventricular hypertrophy, pre-excitation syndrome, LBBB, >1mm depression of resting ST segment, digitalis use, paced ventricular rhythm
A pharmacologic stress test agent commonly used in PH? Dipyridamole or dobutamine?
Is it a vasodilator or ionotrope?
Dipyridamole- vasodilator
Dobutamine - inotrope/chronotrope
Other vasodilators: adenosine, A2a specific antagonist (Regadenoson) - DAA2
Why is dipyridamole contraindicated in patients with COPD?
can block adenosine receptors -> side effects include bronchoconstriction
Describe an ideal cardiac imaging test:
cost effective, accessible, short time of procedure, easy to perform, cause no harm to pts, able to accurately detect disease, can influence outcomes in medical decision making (risk stratification)
MI cascade and imaging modalities
perfusion abnormalities: ____
______: echocardiography/CMR
PA: SPECT/PET/CCTA/CMR
systolic dysfunction
I. Radioactive tracers (Nuclear Imaging) - identify which test type
1) Perfusion tracers, metabolic tracers (fluordeoxyglucose)
2) Thallium 201, Tc-99m setamibi/tetrofosmin
3) Which has a half-life of 72 hours? Which has a half life of 6 hours?
1) PET - proton emission tomography
2) SPECT - single photon emission computed tomography
3) Thallium-201, Tc-99m setamibi/tetrofosmin
SPECT
1) 2 requirements so SPECT tracers can see viability/ischemia
2) Thallium-201 enters through the ____, Tc-99m sestamibi/tetrofosmin enters the _____
1) good bloodflow/perfusion & intact cellular membrane
2) Na/K ATPase pump (it is a K analog); mitochondria
Basic concept of SPECT tracer: describe uptake of healthy myocardium vs with prior MI
healthy - radioisotope uptake
prior MI -> dead myocardium -> no uptake
T/F: SPECT in detecting CAD - 72% sensitivity and 91% for both specificity & normalcy
False. 72% for specificity (ruling in), 91% for sensitivity (ruling out), 91% for normalcy (low risk)
PET Tracer: Identify if perfusion or metabolism tracer
1) Fluorine-18
2) Oxygen-15
3) Rubidium-82
4) Carbon-11
5) Nitrogen-13
Which has the shortest half life?
1) M
2) P
3) P
4) M
5) P
Rubidium-82 (produced by generator, the rest by cyclotron)
T/F: [PET] Mismatch between perfusion & metabolic tracers indicates viable myocardium
True!
Common disadvantage of SPECT & PET? Different disadvantages?
Radiation exposure to patients
SPECT - long duration of procedure, low specificity due to soft tissue artefacts
PET - very expensive, needs a cyclotron or generator to produce the tracers
CMR
1) ___ is used to convert the frequency
information contained in the signal from each location in the
imaged plane to corresponding intensity levels
2) Create the magnetic fields: ___
3) Advantage compared to SPECT & PET
1) Fourier transformation
2) superconducting magnets and sophisticated electronics which manipulate and process the radiofrequency energy
3) No exposure to ionizing radiation
Gives accurate data for CO & myocardial dysfunction, as well as for valvular abnormalities A) PET B) SPECT C) CMR D) CT
CMR - other clinical uses: detect myocardial viability & is an emerging tool for assessment of myocardial perfusion
CMR: Clinical use
shows behavior of of myocardial segments and how these contract
assessment of LV function
CMR: Clinical use
____ stress test
dobutamine (an ionotrope/chronotrope)
CMR: Clinical use - Myocardial tissue characterization & key imaging interests
Late gadolinium enhancement: ___
T2-weighted imaging: ___
Iron content imaging: ____
myocardial infarction and infiltrative disease
myocardial edema
myocardial iron infiltration
