Ultrasound: twinkling 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: twinkling artefact

Sample item

On colour Doppler, a bright echogenic focus in the kidney with posterior shadowing shows a rapidly alternating mosaic of colours behind it, even though no vessel is present. What does this suggest?

AA renal calculus showing the twinkling artefactBA renal artery aneurysmCA vascular malformationDA simple cyst

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

The answer and the reasoning

A. A renal calculus showing the twinkling artefact

A rough, strongly reflecting surface such as a stone produces broadband noise that the machine misreads as flow, causing twinkling. It helps to confirm small stones that shadow poorly. A true vascular lesion would show organised flow.

Option by option

A. A renal calculus showing the twinkling artefact (correct)
Correct. Twinkling behind a hard rough surface is typical of calculi.
B. A renal artery aneurysm
An aneurysm shows organised arterial flow within a lumen.
C. A vascular malformation
A malformation shows organised flow and not just a colour mosaic behind a shadowing focus.
D. A simple cyst
A cyst is anechoic and has posterior enhancement.

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, A renal calculus showing the twinkling artefact. A rough, strongly reflecting surface such as a stone produces broadband noise that the machine misreads as flow, causing twinkling.

Why is "A renal artery aneurysm" not the answer?

An aneurysm shows organised arterial flow within a lumen.

Why is "A vascular malformation" not the answer?

A malformation shows organised flow and not just a colour mosaic behind a shadowing focus.

Why is "A simple cyst" not the answer?

A cyst is anechoic and has posterior enhancement.

What concept does this question test?

It tests Ultrasound: twinkling artefact in Radiology. It helps to confirm small stones that shadow poorly. A true vascular lesion would show organised flow.

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 Ultrasound: twinkling 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.