Chest imaging: aspergilloma: 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.

Try it

Radiology · Chest imaging: aspergilloma

Sample item

A patient with old tuberculosis presents with haemoptysis, and CT shows a mobile rounded soft tissue mass within an upper lobe cavity with a surrounding crescent of air. What is this sign?

AHalo sign of invasive aspergillosisBCavity from lung abscess with air-fluid levelCAir crescent (Monod) sign of aspergillomaDWater-lily sign of hydatid

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

The answer and the reasoning

C. Air crescent (Monod) sign of aspergilloma

A fungus ball in a pre-existing cavity creates a mobile mass separated from the cavity wall by a crescent of air (Monod sign), and it changes position on prone scans. It can cause life-threatening haemoptysis, treated by bronchial artery embolisation or surgery. The halo sign appears in invasive disease in neutropenic patients.

Option by option

A. Halo sign of invasive aspergillosis
The halo sign is ground glass around a nodule in angio-invasive aspergillosis.
B. Cavity from lung abscess with air-fluid level
A lung abscess shows a fluid level and thick wall, without a mobile mass.
C. Air crescent (Monod) sign of aspergilloma (correct)
Correct. Mass within a cavity with a crescent of air is a fungus ball.
D. Water-lily sign of hydatid
The water-lily sign refers to a ruptured hydatid cyst with floating membranes.

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, Air crescent (Monod) sign of aspergilloma. A fungus ball in a pre-existing cavity creates a mobile mass separated from the cavity wall by a crescent of air (Monod sign), and it changes position on prone scans.

Why is "Halo sign of invasive aspergillosis" not the answer?

The halo sign is ground glass around a nodule in angio-invasive aspergillosis.

Why is "Cavity from lung abscess with air-fluid level" not the answer?

A lung abscess shows a fluid level and thick wall, without a mobile mass.

Why is "Water-lily sign of hydatid" not the answer?

The water-lily sign refers to a ruptured hydatid cyst with floating membranes.

What concept does this question test?

It tests Chest imaging: aspergilloma in Radiology. It can cause life-threatening haemoptysis, treated by bronchial artery embolisation or surgery. The halo sign appears in invasive disease in neutropenic 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 Chest imaging: aspergilloma?

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.