Intro to Non-invasive Cardiac Imaging

Question 1

Gold standard for evaluating CAD

Answer 1

coronary angiography

Question 2

Types of exercise stress testing

Answer 2

Treadmill exercise test & bicycle ergometry

Question 3

Parts of the myocardial ischemia cascade

Answer 3

perfusion abnormalities -> diastolic dysfunction -> systolic dysfunction -> ECG changes -> angina

Question 4

Whys is coronary angiography not ideal for screening despite being the gold standard for evaluating CAD?

Answer 4

Due to exposure to radiation and contrast materials, which may
be toxic to some patients. It is an invasive assessment tool.

Question 5

Computation for maximum HR?

Answer 5

220-age

Question 6

Findings of exercise stress testing (hints: EJKs, Blackpink, you’re so FC, Ari, fly high)

Answer 6

EKG ischemic changes, BP responses, functional capacity, arrhythmia, high risk variables

Question 7

Indications for Pharmacologic Stress Testing

1) Inability to exercise (3)
2) Limited exercise capacity (2)
3) Specific ECG findings (3)

Answer 7

1) physical limitations, recent operations, comorbidities
2) deconditioning/poor motivation, limiting physical conditions (COPD, claudication)
3) LV, CLBBB, pacemaker rhythm

Question 8

Resting ECG findings which can give false positive pharmacological stress test: (hints: VH, excited, RBB, sad ST, fingers, pacing)

Answer 8

ventricular hypertrophy, pre-excitation syndrome, LBBB, >1mm depression of resting ST segment, digitalis use, paced ventricular rhythm

Question 9

A pharmacologic stress test agent commonly used in PH? Dipyridamole or dobutamine?

Is it a vasodilator or ionotrope?

Answer 9

Dipyridamole- vasodilator
Dobutamine - inotrope/chronotrope

Other vasodilators: adenosine, A2a specific antagonist (Regadenoson) - DAA2

Question 10

Why is dipyridamole contraindicated in patients with COPD?

Answer 10

can block adenosine receptors -> side effects include bronchoconstriction

Question 11

Describe an ideal cardiac imaging test:

Answer 11

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)

Question 12

MI cascade and imaging modalities

perfusion abnormalities: ____
______: echocardiography/CMR

Answer 12

PA: SPECT/PET/CCTA/CMR

systolic dysfunction

Question 13

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?

Answer 13

1) PET - proton emission tomography
2) SPECT - single photon emission computed tomography
3) Thallium-201, Tc-99m setamibi/tetrofosmin

Question 14

SPECT

1) 2 requirements so SPECT tracers can see viability/ischemia
2) Thallium-201 enters through the ____, Tc-99m sestamibi/tetrofosmin enters the _____

Answer 14

1) good bloodflow/perfusion & intact cellular membrane

2) Na/K ATPase pump (it is a K analog); mitochondria

Question 15

Basic concept of SPECT tracer: describe uptake of healthy myocardium vs with prior MI

Answer 15

healthy - radioisotope uptake

prior MI -> dead myocardium -> no uptake

Question 16

T/F: SPECT in detecting CAD - 72% sensitivity and 91% for both specificity & normalcy

Answer 16

False. 72% for specificity (ruling in), 91% for sensitivity (ruling out), 91% for normalcy (low risk)

Question 17

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?

Answer 17

1) M
2) P
3) P
4) M
5) P

Rubidium-82 (produced by generator, the rest by cyclotron)

Question 18

T/F: [PET] Mismatch between perfusion & metabolic tracers indicates viable myocardium

Answer 18

True!

Question 19

Common disadvantage of SPECT & PET? Different disadvantages?

Answer 19

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

Question 20

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

Answer 20

1) Fourier transformation
2) superconducting magnets and sophisticated electronics which manipulate and process the radiofrequency energy
3) No exposure to ionizing radiation

Question 21

Gives accurate data for CO & myocardial dysfunction, as well as for valvular abnormalities
A) PET
B) SPECT
C) CMR
D) CT

Answer 21

CMR - other clinical uses: detect myocardial viability & is an emerging tool for assessment of myocardial perfusion

Question 22

CMR: Clinical use

shows behavior of of myocardial segments and how these contract

Answer 22

assessment of LV function

Question 23

CMR: Clinical use

____ stress test

Answer 23

dobutamine (an ionotrope/chronotrope)

Question 24

CMR: Clinical use - Myocardial tissue characterization & key imaging interests

Late gadolinium enhancement: ___
T2-weighted imaging: ___
Iron content imaging: ____

Answer 24

myocardial infarction and infiltrative disease
myocardial edema
myocardial iron infiltration

Question 25

CMR: Clinical use
T/F?
Transmurality index: LGE >90% transmurality predicts non-viability, will not benefit from revascularization

Answer 25

False. LGE >75%; LGE<25% transmurality best predicts recover in function

Question 26

CMR: Clinical use

1) May be used to examine the coronary arteries
2) Can detect arrhythmogenic RV dysplasia & fibro-fatty infiltrates
3) Can examine other vascular structure abnormalities within the thorax such as PAPVR

Answer 26

1) Non-invasive angiography by CMR
2) Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC)
3) Partial Anomalous Pulmonary Venous Return (PAPVR)

Question 27

Contraindications for CMR

Answer 27

Patients with pacemakers or implantable cardioverter defibrillators (ICDs) or anything with metal because of strong magnet use
Patients with severe kidney disease (GFR <30 mL/min/1.73m2) due to risk of systemic nephrogenic fibrosis caused by gadolinium-based contrast
Severe claustrophobia (relative)

Question 28

What is coronary artery calcium score?

Answer 28

Non-invasive technique to assess total atherosclerotic burden by
looking at the calcium deposits in the coronary arteries before
doing CCTA

Question 29

CAC score & calcified plaque burden

a) severe plaque burden: __
b) 1-10: ___
c) mild plaque burden: ____

Answer 29

a) 401-1000
b) minimal plaque burden
c) 11-100