Ultrasound: mirror image artefact: 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 · Ultrasound: mirror image artefact

Sample item

Ultrasound of the right liver dome shows a bright lesion in the liver and an apparently identical lesion lying above it, seemingly within the lung. What is the explanation?

AA true second lesion in the right lower lobeBPosterior acoustic enhancementCRefraction shadowing at the edge of a cystDMirror image artefact from the strongly reflecting diaphragm-lung interface

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

The answer and the reasoning

D. Mirror image artefact from the strongly reflecting diaphragm-lung interface

A strong curved reflector such as the diaphragm can redirect the beam so that echoes return by a longer path, and the machine places a duplicate image deeper than the true structure. The duplicate lies beyond the reflector and has no real counterpart. Scanning from another angle makes it disappear.

Option by option

A. A true second lesion in the right lower lobe
Air-filled lung cannot be imaged by ultrasound, so a real lesion would not be shown there.
B. Posterior acoustic enhancement
Enhancement brightens tissue behind a fluid-filled structure and does not duplicate a lesion.
C. Refraction shadowing at the edge of a cyst
Refraction shadows are thin dark lines at the edges of rounded structures.
D. Mirror image artefact from the strongly reflecting diaphragm-lung interface (correct)
Correct. A mirror image forms beyond a strong reflector.

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, Mirror image artefact from the strongly reflecting diaphragm-lung interface. A strong curved reflector such as the diaphragm can redirect the beam so that echoes return by a longer path, and the machine places a duplicate image deeper than the true structure.

Why is "A true second lesion in the right lower lobe" not the answer?

Air-filled lung cannot be imaged by ultrasound, so a real lesion would not be shown there.

Why is "Posterior acoustic enhancement" not the answer?

Enhancement brightens tissue behind a fluid-filled structure and does not duplicate a lesion.

Why is "Refraction shadowing at the edge of a cyst" not the answer?

Refraction shadows are thin dark lines at the edges of rounded structures.

What concept does this question test?

It tests Ultrasound: mirror image artefact in Radiology. The duplicate lies beyond the reflector and has no real counterpart. Scanning from another angle makes it disappear.

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 Ultrasound: mirror image artefact?

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.