CARDIAC Section 2: CORONARY/CARDIAC CT

Question 1

Who is the ideal patient to undergo a coronary CT?

Answer 1

1. Intermediate risk for MI and/or atypical chest pain patients
2. Suspected aberrant coronary anatomy
3. Evaluating stents (larger than 3mm) or CABG patency
4. Preoperative assessment for trancatheter aortic valve iplantation (TAVI/TAVR)

Question 2

What makes someone intermediate risk for a MI?

Answer 2

Framingham Risk Score 10-20%

Question 3

What findings suggest increased risk for a major adverse cardiac event? (MACE)?

Answer 3

A bunch of calcium in the vessels - calculated as a “high Agaston score (>160).

Question 4

What is the ideal heart rate?

Answer 4

Slow heart rate is considered - to reduce motion related artifacts.

< 60 beats/min.

Beta blockers are used

Question 5

What are the contraindications for beta blockers?

Answer 5

Patients with:
1. Severe asthma.
2. heart block
3. acute chest pain
4. Recent drug use

Question 6

Are all heart blocks contraindication to beta blockers?

Answer 6

2nd and 3rd degree blocks are contraindication.

A 1st degree block is NOT!

Question 7

What if I can’t give the beta blocker?

Answer 7

Yes.

You can’t use a prospective gating technique.

You’ll have to use RESTROPSECTIVE gating.

Question 8

What is the difference between prospective and retrospective gating?

Answer 8

• Prospective: Step and shoot - R-R interval data aquisition triggered by R Wave
• Retrospective: Scans the whole time, then back calculates

Question 9

What are the pros of Prospective Gating?

Answer 9

Reduced radiation because the scanner isn’t on the whole time

Question 10

What are the cons of Prospective gating?

Answer 10

No functional imaging
More sensitive to heart rate variability (high hear rate or irregular rythm)

Question 11

Difference of Prospective and Retrospective cuts?

Answer 11

Prospective: Always AXIAL

Retrospective: Always HELICAL

Question 12

What are the pros of Retrospective Gating?

Answer 12

• Can do functional imaging
• Less sensitive to heart rate variability

Question 13

What are the cons of retrospective gating?

Answer 13

Higher radiation (use of low pitch - increases dose)

Question 14

What component(s) of the cardiac cycle trigger imaging acquisition?

Answer 14

Prospective: Data acquisition triggered by R wave
Retrospective: Date is acquired throughout the cardiac cycle

Question 15

What is best for valvular evaluation?

Answer 15

Retrospective: This is required for evaluating MITRAL and TRICUSPID valves

Question 16

What are the other drugs given for coronary CT, aside from beta blockers?

Answer 16

Nitroglycerine - to dilate the coronaries (so you can see them better)

Question 17

What are the contraindications to nitroglycerine?

Answer 17

1. Hypotension (SBP <100)
2. Severe aortic stenosis
3. hypertrophic obstructing cardiomyopathy
4. Phosphodiesterase (Viagra-Sildefanil - “BONER pills) use