Chest and cardiac imaging: hilum overlay 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 · Chest and cardiac imaging: hilum overlay sign

Sample item

A PA chest radiograph shows a large rounded opacity projected over the left hilum, but the hilar vessels remain visible through it. What does this tell you?

AThe finding is a loculated pleural effusionBThe mass arises from the hilumCThe mass lies anterior or posterior to the hilum rather than arising from itDThe finding is a left lower lobe collapse

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

The answer and the reasoning

C. The mass lies anterior or posterior to the hilum rather than arising from it

The hilum overlay sign states that if the hilar vessels can be seen through an apparent hilar mass, the mass is not in the hilum but lies in front of it or behind it, in the anterior or posterior mediastinum. A true hilar mass obscures the vessels. The sign helps decide where to look on the lateral view or CT.

Option by option

A. The finding is a loculated pleural effusion
A loculated effusion has pleural-based margins and does not suggest this location.
B. The mass arises from the hilum
A mass arising from the hilum would hide the vessels.
C. The mass lies anterior or posterior to the hilum rather than arising from it (correct)
Correct. Visible hilar vessels show the mass is separate from the hilum.
D. The finding is a left lower lobe collapse
Lower lobe collapse gives a triangular retrocardiac density.

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, The mass lies anterior or posterior to the hilum rather than arising from it. The hilum overlay sign states that if the hilar vessels can be seen through an apparent hilar mass, the mass is not in the hilum but lies in front of it or behind it, in the anterior or posterior mediastinum.

Why is "The finding is a loculated pleural effusion" not the answer?

A loculated effusion has pleural-based margins and does not suggest this location.

Why is "The mass arises from the hilum" not the answer?

A mass arising from the hilum would hide the vessels.

Why is "The finding is a left lower lobe collapse" not the answer?

Lower lobe collapse gives a triangular retrocardiac density.

What concept does this question test?

It tests Chest and cardiac imaging: hilum overlay sign in Radiology. A true hilar mass obscures the vessels. The sign helps decide where to look on the lateral view or CT.

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 Chest and cardiac imaging: hilum overlay 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.