Imaging modalities and physics: unknown aneurysm clip before MRI: practice question

A Radiology question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

Try it

Radiology · Imaging modalities and physics: unknown aneurysm clip before MRI

Sample item

A man had intracranial aneurysm surgery abroad in the 1980s and now needs MRI for a spinal complaint. The clip type is unknown and no implant card is available. What is the safest decision?

ADo not scan with MRI until the clip is documented as MR-conditional, and use CT if imaging is urgentBGive a sedative so the clip does not move during the scanCProceed at 3 tesla with a lower SAR to reduce heatingDProceed with MRI because intracranial clips are always non-magnetic

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

A. Do not scan with MRI until the clip is documented as MR-conditional, and use CT if imaging is urgent

Older aneurysm clips may be ferromagnetic and can twist or dislodge in the field, causing fatal haemorrhage. An unidentified clip is treated as a contraindication until its model is confirmed MR-conditional. CT or another non-MRI modality is used meanwhile.

Option by option

A. Do not scan with MRI until the clip is documented as MR-conditional, and use CT if imaging is urgent (correct)
Correct. Unknown clips are treated as unsafe until documented otherwise.
B. Give a sedative so the clip does not move during the scan
Sedation does nothing to the magnetic force acting on the clip.
C. Proceed at 3 tesla with a lower SAR to reduce heating
Torque on a ferromagnetic clip is worse at higher field strength, and SAR does not address it.
D. Proceed with MRI because intracranial clips are always non-magnetic
Many older clips are ferromagnetic, so this assumption is dangerous.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

Questions about this Radiology question

What is the answer to this Radiology question?

The best answer is A, Do not scan with MRI until the clip is documented as MR-conditional, and use CT if imaging is urgent. Older aneurysm clips may be ferromagnetic and can twist or dislodge in the field, causing fatal haemorrhage.

Why is "Give a sedative so the clip does not move during the scan" not the answer?

Sedation does nothing to the magnetic force acting on the clip.

Why is "Proceed at 3 tesla with a lower SAR to reduce heating" not the answer?

Torque on a ferromagnetic clip is worse at higher field strength, and SAR does not address it.

Why is "Proceed with MRI because intracranial clips are always non-magnetic" not the answer?

Many older clips are ferromagnetic, so this assumption is dangerous.

What concept does this question test?

It tests Imaging modalities and physics: unknown aneurysm clip before MRI in Radiology. An unidentified clip is treated as a contraindication until its model is confirmed MR-conditional. CT or another non-MRI modality is used meanwhile.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Imaging modalities and physics: unknown aneurysm clip before MRI?

Learn signs with the image, and the disease they point to. Then use the flashcards and the other Radiology questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.