Imaging modalities and physics: slice cross-talk: 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: slice cross-talk

Sample item

In a multislice T2-weighted spin-echo acquisition with contiguous slices, signal is reduced in the images because adjacent slice excitations overlap. How is this artefact reduced?

AIncreasing the field of viewBShortening the repetition timeCLeaving a gap between slices or acquiring them in an interleaved orderDUsing a higher flip angle

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

The answer and the reasoning

C. Leaving a gap between slices or acquiring them in an interleaved order

Imperfect slice profiles excite neighbouring slices, so tissue there is partly saturated and loses signal, a problem called cross-talk. Using inter-slice gaps or interleaved acquisition reduces it. The other changes do not address the overlapping excitation.

Option by option

A. Increasing the field of view
A larger field of view does not change slice profiles.
B. Shortening the repetition time
A shorter repetition time increases saturation and makes cross-talk worse.
C. Leaving a gap between slices or acquiring them in an interleaved order (correct)
Correct. A gap or interleaving prevents neighbouring slices saturating each other.
D. Using a higher flip angle
A higher flip angle increases saturation of neighbouring tissue and worsens the effect.

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 C, Leaving a gap between slices or acquiring them in an interleaved order. Imperfect slice profiles excite neighbouring slices, so tissue there is partly saturated and loses signal, a problem called cross-talk.

Why is "Increasing the field of view" not the answer?

A larger field of view does not change slice profiles.

Why is "Shortening the repetition time" not the answer?

A shorter repetition time increases saturation and makes cross-talk worse.

Why is "Using a higher flip angle" not the answer?

A higher flip angle increases saturation of neighbouring tissue and worsens the effect.

What concept does this question test?

It tests Imaging modalities and physics: slice cross-talk in Radiology. Using inter-slice gaps or interleaved acquisition reduces it. The other changes do not address the overlapping excitation.

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: slice cross-talk?

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.