Imaging modalities and physics: surface coils: 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.

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Radiology · Imaging modalities and physics: surface coils

Sample item

A radiologist images the small orbit and optic nerve and wants the best signal-to-noise ratio. Which change gives the greatest improvement?

AUsing a small receiver coil placed close to the orbitBReducing the number of signal averagesCEnlarging the field of view to include the whole head and neckDUsing only the large body coil for reception

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

The answer and the reasoning

A. Using a small receiver coil placed close to the orbit

A small surface coil close to the region of interest picks up less noise from distant tissue and so raises signal-to-noise ratio for superficial structures. The body coil, a larger field of view and fewer averages all reduce it.

Option by option

A. Using a small receiver coil placed close to the orbit (correct)
Correct. A close small coil raises signal and limits noise from distant tissue.
B. Reducing the number of signal averages
Fewer averages reduce signal-to-noise ratio in proportion to the square root of their number.
C. Enlarging the field of view to include the whole head and neck
A larger field of view enlarges voxels in relative terms of coverage and does not help a small structure.
D. Using only the large body coil for reception
The body coil sees a large volume and collects more noise with weaker local signal.

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, Using a small receiver coil placed close to the orbit. A small surface coil close to the region of interest picks up less noise from distant tissue and so raises signal-to-noise ratio for superficial structures.

Why is "Reducing the number of signal averages" not the answer?

Fewer averages reduce signal-to-noise ratio in proportion to the square root of their number.

Why is "Enlarging the field of view to include the whole head and neck" not the answer?

A larger field of view enlarges voxels in relative terms of coverage and does not help a small structure.

Why is "Using only the large body coil for reception" not the answer?

The body coil sees a large volume and collects more noise with weaker local signal.

What concept does this question test?

It tests Imaging modalities and physics: surface coils in Radiology. The body coil, a larger field of view and fewer averages all reduce it.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. 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: surface coils?

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.