CAMRT Contrast Media and Pharmacology Questions and Answers 3

Question 1

What is the mechanism of contrast-induced nephropathy, and who is at highest risk?

Accepted Answer

Direct tubular toxicity and renal vasoconstriction; patients with renal insufficiency and diabetes

Answer

Allergic tubular inflammation; shellfish allergy patients

Answer

Immune complex deposition; autoimmune patients

Answer

Mechanical obstruction; kidney stone patients

Question 2

Oesophageal perforation is suspected during a barium swallow. Which contrast should be used?

Accepted Answer

Water-soluble low-osmolality non-ionic contrast

Answer

Gastrografin

Answer

Air contrast only

Answer

Gadolinium

Question 3

What is the appropriate action when contrast extravasation is detected during power injection?

Accepted Answer

Stop immediately, elevate the limb, apply cold compress

Answer

Continue at slower rate

Answer

Withdraw contrast with a syringe

Answer

Apply a tourniquet

Question 4

What distinguishes ionic from non-ionic iodinated contrast media?

Accepted Answer

Non-ionic agents do not dissociate, resulting in lower osmolality

Answer

Ionic agents contain more iodine per molecule

Answer

Ionic agents are water-soluble while non-ionic are oil-based

Answer

Non-ionic agents are always iso-osmolar

Question 5

A patient with pheochromocytoma is scheduled for contrast CT. What risk must the technologist know?

Accepted Answer

Potential hypertensive crisis from catecholamine release

Answer

Increased contrast allergy risk

Answer

Rapid contrast excretion

Answer

Increased extravasation risk

Question 6

What is the current Canadian fasting protocol for elective contrast-enhanced CT?

Accepted Answer

No fasting required; adequate hydration encouraged

Answer

NPO 12 hours

Answer

NPO 8 hours, clear fluids until 2 hours before

Answer

NPO 4 hours solids, 2 hours clear fluids