MRI MRI Contrast Agents 2

Question 1

Gadolinium retention in the brain has been observed particularly in which structure on unenhanced T1-weighted images in patients receiving multiple GBCA doses?

Accepted Answer

Dentate nucleus of the cerebellum

Answer

Gadolinium deposition in the dentate nucleus and globus pallidus manifests as T1 hyperintensity on unenhanced brain MRI after multiple GBCA administrations.

Question 2

Which of the following best describes a blood-pool GBCA used in MR angiography?

Accepted Answer

It binds reversibly to albumin, prolonging intravascular residence time

Answer

Blood-pool agents (e.g., gadofosveset) bind reversibly to albumin, extending their half-life in the vascular space and allowing steady-state MRA over a longer acquisition window.

Question 3

For a contrast-enhanced MRA of the aorta, the bolus tracking technique monitors contrast arrival in which vessel to trigger the 3D acquisition?

Accepted Answer

Abdominal aorta or descending thoracic aorta at the level of interest

Answer

A monitoring slice is placed at the aorta at the target level; when the contrast bolus arrives (signal threshold), the 3D acquisition is automatically triggered.

Question 4

Which of the following is the correct management for a patient who experiences an acute severe allergic-like reaction (anaphylaxis) following GBCA injection?

Accepted Answer

Stop contrast injection, call code team, administer epinephrine 0.3 mg IM (1:1000)

Answer

Anaphylaxis requires immediate cessation of injection, emergency team activation, and epinephrine 0.3 mg IM (1:1000 concentration) in the lateral thigh as first-line treatment.

Question 5

What is the primary advantage of using a higher-relaxivity GBCA (e.g., gadobenate dimeglumine) compared to a standard-relaxivity agent?

Accepted Answer

It can be used at a lower dose to achieve comparable enhancement

Answer

Higher relaxivity means greater T1 shortening per unit concentration, so a lower molar dose can produce equivalent or superior enhancement compared to standard agents.

MRI - Magnetic Resonance Imaging Practice Test

MRI - Magnetic Resonance Imaging Practice Test

MRI MRI Contrast Agents 2