Computed Tomography Test CT Contrast Media and Patient Preparation 2

Question 1

What type of adverse reaction to iodinated contrast media involves an immune-mediated hypersensitivity response?

Accepted Answer

Anaphylactoid (allergy-like) reaction

Answer

Anaphylactoid reactions mimic true anaphylaxis (urticaria, bronchospasm, hypotension) but do not require prior sensitization and are not IgE-mediated.

Question 2

A patient experiences mild urticaria after CT contrast injection. What is the most appropriate immediate action?

Accepted Answer

Administer diphenhydramine (Benadryl) and observe the patient

Answer

Mild urticaria (hives only, no systemic symptoms) is treated with antihistamines and close observation while monitoring for progression to a more severe reaction.

Question 3

What is the recommended fasting time before IV contrast-enhanced CT in non-emergency patients?

Accepted Answer

4 hours NPO for solids

Answer

A 4-hour fast is recommended before contrast CT to reduce aspiration risk in the event of nausea or vomiting, while preventing dehydration.

Question 4

Which factor most significantly increases a patient's risk for a severe contrast reaction?

Accepted Answer

History of a prior severe contrast reaction

Answer

A prior severe contrast reaction is the single strongest risk factor for a repeat severe reaction, increasing risk approximately 5-fold.

Question 5

What technique is used to time the CT acquisition to arterial contrast peak in CT angiography?

Accepted Answer

Bolus tracking (SmartPrep) or test bolus technique

Answer

Bolus tracking uses real-time low-dose monitoring of a target vessel; when attenuation reaches a threshold, the diagnostic scan is automatically triggered.

Computed Tomography Test Practice Test

Computed Tomography Test Practice Test

Computed Tomography Test CT Contrast Media and Patient Preparation 2