MRI MRI Safety 2 — Questions and Answers
Question 1: Which MRI screening form section is most critical for identifying implanted devices that may be MR Unsafe?
- Allergies section
- Implants and devices section (Correct answer)
- Surgical history section
- Medication list section
Correct answer: Implants and devices section
The implants and devices section identifies items such as pacemakers, cochlear implants, and aneurysm clips that may be MR Unsafe.
Question 2: What is a 'quench' in MRI terminology?
- A rapid increase in field strength
- A sudden loss of superconductivity causing helium boil-off (Correct answer)
- A gradient coil failure
- A patient motion artifact
Correct answer: A sudden loss of superconductivity causing helium boil-off
A quench occurs when the superconducting magnet loses its superconducting state, causing liquid helium to vaporize rapidly and potentially displacing oxygen in the room.
Question 3: MR Conditional implants are safe to scan only when:
- The patient gives verbal consent
- Specific conditions of field strength, SAR, and gradient limits are met (Correct answer)
- The radiologist approves verbally
- The scan time is under 30 minutes
Correct answer: Specific conditions of field strength, SAR, and gradient limits are met
MR Conditional devices are safe only when the defined conditions of use (field strength, SAR, gradient dB/dt, scan duration) are strictly followed.
Question 4: Which of the following is a documented risk of MRI during the first trimester of pregnancy?
- Ionizing radiation exposure
- Gadolinium retention in fetal tissue
- Acoustic noise damage to fetal hearing
- All of the above except ionizing radiation (Correct answer)
Correct answer: All of the above except ionizing radiation
MRI does not use ionizing radiation, but first-trimester risks include acoustic noise and potential gadolinium retention; non-contrast scanning is preferred.
Question 5: What minimum distance from the MRI magnet bore is generally recommended to keep unsecured ferromagnetic oxygen cylinders?
- 1 meter
- 3 meters
- 5 meters
- Distance depends on field strength and cylinder size (Correct answer)
Correct answer: Distance depends on field strength and cylinder size
The safe exclusion zone for ferromagnetic oxygen cylinders depends on both the scanner's field strength and the cylinder size, so no single fixed distance applies universally.
Question 6: Which labeling term indicates that an item has been tested and poses no known hazards in ALL MRI environments?
- MR Conditional
- MR Compatible
- MR Safe (Correct answer)
- MR Approved
Correct answer: MR Safe
The ASTM 'MR Safe' label means the item poses no known hazards in all MRI environments and is made of non-conductive, non-magnetic, non-RF-reactive materials.
MRI MRI Safety 2
Which MRI screening form section is most critical for identifying implanted devices that may be MR Unsafe?