Contrast agents

Question 1

Which phase is MR contrast ued during?

Answer 1

T1

Question 2

What is the benifits/disadvantages of ionic iodinated contrast?

Answer 2

Higher osmolarity
more side efects

Question 3

What is the benifits/disadvantages of non-ionic iodinated contrast?

Answer 3

Lower osmolality
less side efects
toxicity decreases as osmolality approaches equal to the serum

Question 4

What are examples of MR contrast and their magnetism?

Answer 4

gadolinium - paramagnetic
iron oxide - superparamagnetic
Iron platinum - superparamagnetic
Manganese - paramagnetic

Question 5

What antibody is responsible for adverse reactions?

Answer 5

IgE

Question 6

What is the mechanism behind adverse contrast reactions?

Answer 6

Direct release of histamine
Contrast molecule causes an effect on antigen binding sites on IgE of mast cells.
Severity of reaction depends on quantity of circulating IgE and mast cells
or due to direct contact with blood vessel endothelium. This leads to an activation of factor XII (12) -> prostaglandins -> leukotrienes (like histamines)