MRI MRI Contrast Agents 3

Question 1

Iron oxide nanoparticles (e.g., USPIO) used as MRI contrast agents primarily shorten which relaxation time?

Accepted Answer

T2 and T2* (susceptibility effect)

Answer

T1 only

Answer

Neither T1 nor T2

Answer

T2 only with no T2* effect

Question 2

A patient with a GFR of 45 mL/min/1.73m² requires a contrast-enhanced MRI. According to ACR guidelines, which GBCA group is preferred?

Accepted Answer

Group III macrocyclic agents

Answer

Group I linear ionic agents

Answer

Group II linear non-ionic agents

Answer

Contrast should be completely avoided

Question 3

The 'late gadolinium enhancement' (LGE) pattern of subendocardial distribution in cardiac MRI is most consistent with which diagnosis?

Accepted Answer

Ischemic scar (prior myocardial infarction)

Answer

Hypertrophic cardiomyopathy

Answer

Myocarditis

Answer

Cardiac sarcoidosis

Question 4

What is the primary reason gadolinium-based contrast agents should not be used in patients undergoing hemodialysis without a specific clinical indication?

Accepted Answer

Risk of NSF remains even after hemodialysis removes gadolinium

Answer

Risk of anaphylaxis is higher in dialysis patients

Answer

Gadolinium is not effectively removed by standard hemodialysis

Answer

Dialysis filters destroy the contrast agent before it reaches the target tissue

Question 5

In dynamic contrast-enhanced (DCE) MRI of the breast, which kinetic enhancement curve pattern is most concerning for malignancy?

Accepted Answer

Washout (type III)

Answer

Persistent (type I)

Answer

Plateau (type II)

Answer

No enhancement

Question 6

Which of the following precautions is required before administering a GBCA to a breastfeeding mother, according to ACR recommendations?

Accepted Answer

No precautions are required as only trace amounts enter breast milk

Answer

Breastfeeding must be permanently stopped

Answer

Breastfeeding should be interrupted for 24–48 hours after GBCA administration

Answer

The infant must receive a blood test before the mother can resume breastfeeding