Contrast Agents

Question 1

What are three examples of negative contrast agents

Answer 1

1. Air
2. O2
3. CO2

Question 2

Of the three negative contrast agents (air, o2, and co2) which is the best option and why

Answer 2

CO2 bc it dissolves in plasma and is eliminated quickly from the lungs, reducing the risk of air embolism or stroke

Question 3

What is double contrast

Answer 3

Using positive and negative contrast agents

Question 4

Two reasons to use double contrast (positive and negative)

Answer 4

1. View radiolucent bladder stones
2. Detailed view of inner lining of organ/ body cavity

Question 5

What makes barium a good positive contrast agent for the GI tract

Answer 5

It is insoluble and therefore is not absorbed and not diluted

Question 6

What are the risks for using barium as a contrast agent

Answer 6

1. Aspiration into the lungs
2. Leaks into abdomen or thorax (emergency)

Question 7

Why is iodine not a good contrast agent for the GI tract

Answer 7

It is water soluble and therefore quickly absorbed into blood vessels before reaching lower GI tract

Question 8

Why are iodine agents a good choice of contrast for kidneys

Answer 8

Since they are water soluble, they are absorbed into the blood vessels and excreted by the kidneys, making them more visible

Question 9

Ionic (charged) contrast agents can be given by what three routes

Answer 9

1. Oral
2. IV
3. Intraluminal

Question 10

Hypertonic contrast agents become ____________ due to their osmotic pull and therefore should not be given to an animal that is ________________

Answer 10

Diluted
Dehydrated
(weak contrast agents once diluted)