Ch10 - MRI Safety Practice Questions

According to ACR guidelines, Zone IV represents which area of the MRI suite?

A. MRI control room

B. Area accessible only to non-MRI personnel

C. MRI scanner room with the strongest magnetic field

D. Patient holding area

C. MRI scanner room with the strongest magnetic field

Which personnel group includes individuals who have minimal safety training and may work in Zone III?

A. Non-MRI personnel

B. Level 1 personnel

C. Level 2 personnel

D. Visitors

B. Level 1 personnel

An implant that poses no known hazards in all MRI environments is labeled:

A. MR Conditional

B. MR Compatible

C. MR Safe

D. MR Unsafe

C. MR Safe

Which of the following is considered an outdated term and should not be used?

A. MR Conditional

B. MR Compatible

C. MR Unsafe

D. MR Safe

B. MR Compatible

Closed-bore scanners primarily increase the risk of which psychological effect?

A. Confusion

B. Hallucinations

C. Claustrophobia and anxiety

D. Memory loss

C. Claustrophobia and anxiety

Vertigo, dizziness, and nystagmus from static magnetic fields are most likely to occur at:

A. 0.3T

B. 1.5T

C. 3.0T

D. 7.0T or higher

D. 7.0T or higher

The 5-gauss line is associated with what major MRI safety concern?

A. Thermal burns

B. Projectile accidents

C. RF heating

D. Gradient-induced nerve stimulation

B. Projectile accidents

Quenching the magnet is justified when:

A. A patient experiences mild claustrophobia

B. A life-threatening projectile incident occurs

C. The scanner overheats

D. Scan time must be reduced

B. A life-threatening projectile incident occurs

Torque on implanted devices is caused by:

A. RF absorption

B. Time-varying gradients

C. Interaction with B0

D. Cryogen instability

C. Interaction with B0

SAR is measured in which units?

A. Decibels

B. Watts per kilogram

C. Tesla per second

D. Joules per meter

B. Watts per kilogram

According to IEC guidelines, the body cannot exceed what temperature increase during RF exposure?

A. 0.5 °C

B. 1.0 °C

C. 2.0 °C

D. 5.0 °C

B. 1.0 °C

A technologist may need approval to exceed Normal Mode and enter First-Level Mode

when:

A. Gradient switching is too slow

B. The SAR limit would be exceeded

C. The patient is claustrophobic

D. The cryogen level is low

B. The SAR limit would be exceeded

Which intervention reduces SAR?

A. Increasing flip angle

B. Using a higher field strength

C. Decreasing the number of slices

D. Adding more sat bands

C. Decreasing the number of slices

Burns can occur when:

A. Arms or legs form natural conductive loops

B. The patient is placed prone

C. TR is increased

D. The gradient coil is cooled

A. Arms or legs form natural conductive loops

The antenna effect occurs when implants of certain lengths absorb RF. Which length is risky at 1.5T?

A. 6 cm

B. 13 cm

C. 26 cm

D. 40 cm

C. 26 cm

Peripheral nerve stimulation from gradients is caused by:

A. Excess SAR

B. Quenching

C. Induced electrical currents

D. Low field strength

C. Induced electrical currents

Gradient-induced cardiac or diaphragm stimulation is related to:

A. RF heating

B. Time-varying magnetic fields

C. Spatial gradient forces

D. Cryogen boil-off

B. Time-varying magnetic fields

Acoustic noise in MRI is caused by:

A. RF coil vibration

B. Patient movement

C. Lorentz forces on gradient coils

D. Eddy currents

C. Lorentz forces on gradient coils

Which cryogen is used in superconducting MRI systems?

A. Liquid nitrogen

B. Liquid helium

C. Liquid argon

D. Liquid oxygen

B. Liquid helium

If a technologist is unsure about a patient’s safety for MRI, the correct action is to:

A. Scan using only T1-weighted imaging

B. Proceed if the patient was scanned previously

C. Postpone the exam until safety is confirmed

D. Increase gradient strength for clarity

C. Postpone the exam until safety is confirmed