Neuroimaging: swallow tail sign: 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 · Neuroimaging: swallow tail sign

Sample item

On high-resolution susceptibility-weighted MRI of the midbrain in a healthy person, a bilateral swallow tail pattern of dorsolateral nigral hyperintensity is seen. Its loss supports which diagnosis?

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

The answer and the reasoning

C. Parkinson disease from nigrosome-1 degeneration

The swallow tail sign represents normal nigrosome-1 in the substantia nigra. In Parkinson disease nigral neurons degenerate and the sign is lost, which helps separate it from essential tremor. It is a useful adjunct to clinical diagnosis.

Option by option

  • A. Wilson disease

    Wilson disease shows other midbrain and basal ganglia changes.

  • B. Huntington disease

    Huntington disease causes caudate atrophy.

  • C. Parkinson disease from nigrosome-1 degeneration (correct)

    Correct. Loss of the swallow tail sign supports Parkinson disease.

  • D. Essential tremor

    Essential tremor retains the sign.

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.

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Questions about this Radiology question

What is the answer to this Radiology question?

The best answer is C, Parkinson disease from nigrosome-1 degeneration. The swallow tail sign represents normal nigrosome-1 in the substantia nigra.

Why is "Wilson disease" not the answer?

Wilson disease shows other midbrain and basal ganglia changes.

Why is "Huntington disease" not the answer?

Huntington disease causes caudate atrophy.

Why is "Essential tremor" not the answer?

Essential tremor retains the sign.

What concept does this question test?

It tests Neuroimaging: swallow tail sign in Radiology. In Parkinson disease nigral neurons degenerate and the sign is lost, which helps separate it from essential tremor. It is a useful adjunct to clinical diagnosis.

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 Neuroimaging: swallow tail sign?

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.