Computed Tomography Test CT Contrast Media and Patient Preparation 3

Question 1

What is the standard iodine concentration range (in mg I/mL) for contrast agents commonly used in diagnostic CT?

Accepted Answer

300–370 mg I/mL

Answer

100–150 mg I/mL

Answer

500–600 mg I/mL

Answer

50–100 mg I/mL

Question 2

Which intravenous catheter gauge is recommended for power injection during contrast-enhanced CT?

Accepted Answer

18–20 gauge

Answer

24–26 gauge

Answer

14 gauge or larger

Answer

Any gauge is acceptable

Question 3

A thyroid cancer patient requires radioiodine ablation therapy. Why must iodinated CT contrast be avoided before this treatment?

Accepted Answer

Iodinated contrast saturates the sodium-iodide symporter, blocking therapeutic radioiodine uptake

Answer

It causes thyroid storm

Answer

It permanently destroys the thyroid gland

Answer

It interferes with TSH levels only

Question 4

What is the primary advantage of using saline flush after contrast injection in CT?

Accepted Answer

Pushes residual contrast into central circulation, improving vascular opacification and reducing dose

Answer

Prevents nephrotoxicity

Answer

Reduces scan time

Answer

Increases image noise

Question 5

Which pre-medication regimen is typically used for patients with prior moderate contrast reactions undergoing non-emergent contrast CT?

Accepted Answer

Oral prednisone 13 hours, 7 hours, and 1 hour before, plus diphenhydramine 1 hour before

Answer

Single dose of epinephrine before the scan

Answer

IV methylprednisolone 30 minutes before only

Answer

No premedication is effective

Question 6

Dual-energy CT (DECT) can be used to create virtual non-contrast (VNC) images. What does this eliminate for the patient?

Accepted Answer

The need for a separate pre-contrast CT acquisition

Answer

The need for IV access

Answer

Post-processing time

Answer

The use of a contrast injector