Contrast Media and Pharmacology Flashcards

Gadolinium-based contrast agents (GBCAs) are primarily used in which imaging modality?

Answer: Magnetic resonance imaging (MRI)

Gadolinium-based contrast agents are paramagnetic and used in MRI to shorten T1 relaxation times, producing bright enhancement on T1-weighted images.

The term 'contrast extravasation' refers to:

Answer: Leakage of IV contrast from the vein into surrounding soft tissue

Contrast extravasation occurs when the IV needle or catheter is not properly positioned, allowing contrast to leak into the perivascular soft tissues rather than flowing into the vein.

Which pharmacological agent is used to treat severe bronchospasm as part of a contrast reaction emergency?

Answer: Epinephrine (adrenaline)

Epinephrine is the drug of choice for anaphylaxis and severe bronchospasm because it causes bronchodilation (β2), vasoconstriction (α1), and positive cardiac effects to reverse anaphylaxis.

The 'nephrogram phase' in contrast-enhanced CT occurs approximately how long after IV contrast injection?

Answer: 80–120 seconds after injection

The nephrogram phase (also called the parenchymal phase) occurs 80–120 seconds after IV contrast injection when the renal cortex and medulla opacify uniformly as contrast is filtered by the nephrons.

Which patient condition requires the greatest caution and individualized risk-benefit assessment before administering iodinated IV contrast?

Answer: Chronic kidney disease with eGFR 20 mL/min/1.73m²

An eGFR of 20 mL/min/1.73m² represents severe chronic kidney disease, placing the patient at significant risk for contrast-induced acute kidney injury and requiring careful risk-benefit evaluation.

The concentration of iodinated contrast is expressed in mg of iodine per milliliter (mgI/mL). For a standard CT abdomen/pelvis using 350 mgI/mL contrast at a volume of 100 mL, what is the total iodine dose?

Answer: 35,000 mg (35 g) of iodine

Total iodine dose = concentration × volume = 350 mgI/mL × 100 mL = 35,000 mg (35 grams) of iodine. This calculation is important for monitoring cumulative dose in multi-phase studies.