Imaging modalities and physics: tissue harmonic imaging: 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: tissue harmonic imaging

Sample item

In an obese patient, abdominal ultrasound is noisy with clutter in the near field. Switching to tissue harmonic imaging improves the picture because it:

AIncreases transmit power to enhance penetrationBRemoves the need for time-gain compensationCLowers the transmitted frequency to reduce attenuationDUses echoes at twice the transmitted frequency generated within the tissue

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

The answer and the reasoning

D. Uses echoes at twice the transmitted frequency generated within the tissue

Harmonic signals build up as the beam travels through tissue, so they are not produced in the near-field fat layers where clutter and side lobes arise. The receiver listens at twice the transmitted frequency, which improves contrast resolution in difficult patients.

Option by option

A. Increases transmit power to enhance penetration
Output power is not raised, and higher power would not remove clutter.
B. Removes the need for time-gain compensation
Time-gain compensation is still needed to compensate for attenuation with depth.
C. Lowers the transmitted frequency to reduce attenuation
The receive frequency is higher, not lower, than the transmitted frequency.
D. Uses echoes at twice the transmitted frequency generated within the tissue (correct)
Correct. The harmonic echo is formed deep to the abdominal wall, and this cuts near-field clutter.

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 D, Uses echoes at twice the transmitted frequency generated within the tissue. Harmonic signals build up as the beam travels through tissue, so they are not produced in the near-field fat layers where clutter and side lobes arise.

Why is "Increases transmit power to enhance penetration" not the answer?

Output power is not raised, and higher power would not remove clutter.

Why is "Removes the need for time-gain compensation" not the answer?

Time-gain compensation is still needed to compensate for attenuation with depth.

Why is "Lowers the transmitted frequency to reduce attenuation" not the answer?

The receive frequency is higher, not lower, than the transmitted frequency.

What concept does this question test?

It tests Imaging modalities and physics: tissue harmonic imaging in Radiology. The receiver listens at twice the transmitted frequency, which improves contrast resolution in difficult patients.

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: tissue harmonic imaging?

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.