Contrast Agents In Radiology

Question 1

What is a contrast agent?

Answer 1

Chemical agent administered to patient for a scan which improves contrast resolution in order to differentiate between different types of tissue + identify pathology

Question 2

How can a contrast agent be given?

Answer 2

• intravenously
• intraarterial
• orally
• rectally
• any cavity e,g, urinary bladder

Question 3

What are the types of contrast for X-rays?
Examples

Answer 3

• positive contrast: radiopaque (blocks x rays) e.g. barium or iodine
• negative contrast: radiolucent (doesn’t block x rays) e.g. air or CO2

Question 4

What contrast agents are used in MRIs?
How does it work?

Answer 4

**Gadolinium based agents **
Interferes with how proteins behave in magnetic field

Question 5

What contrast agent is used in ultrasounds?
How does it work?

Answer 5

Microbubbles
Interact with sound waves

Question 6

What contrast agent is used in CT scans?
How does it work?

Answer 6

Iodine
Radiopaque
Blocks x rays

Question 7

Ideal characteristics of contrast agents

Answer 7

Biologically inert
Safe + non toxic
Soluble in water
Cost-effective

Question 8

Types of adverse reactions to contrast agents

Answer 8

Idiosyncratic
Non-idiosyncratic (more common)

Question 9

Idiosyncratic reactions &** DO WE NEED TO KNOW