Name the form by the host: a fungus ball in an old cavity (aspergilloma), progressive cavitation with pleural thickening (chronic pulmonary), central bronchiectasis with high-attenuation mucus (ABPA), or nodules with a halo in a neutropenic patient (angioinvasive).
Orient first
- The same organism causes opposite diseases depending on immunity: colonisation (aspergilloma), hypersensitivity (ABPA), slow invasion (chronic pulmonary aspergillosis) and fast angioinvasion (neutropenia).
- In neutropenia the halo sign (ground glass around a nodule = haemorrhage) is early; the air-crescent sign appears late, at marrow recovery.
- A reversed halo in a neutropenic patient raises mucormycosis — the treatment differs.
Acquire the study
- Thin-section CT chest (non-contrast for nodules; contrast for vessels, pleura and complications); prone images to show a mobile fungus ball.
The manoeuvre
- Aspergilloma: a mass within a pre-existing cavity (old TB, sarcoid) with an air crescent; prone images show it moves.
- Chronic pulmonary aspergillosis: new or enlarging cavities over ≥ 3 months, wall thickening, adjacent pleural thickening.
- ABPA: central (upper-lobe) bronchiectasis with mucus plugging; mucus denser than paraspinal muscle (high-attenuation mucus); finger-in-glove opacities.
- Angioinvasive: nodules or wedge consolidation with a surrounding ground-glass halo; later cavitation and air crescent; look for vessel occlusion.
- State the host (neutropenia, transplant, asthma, prior cavity) — it decides which form the pattern means.
What confirms it
- A CT pattern matched to the host, with mycology (galactomannan, culture, specific IgE/IgG) confirming the form.
What licenses you to exclude it
- A normal CT in a febrile neutropenic patient makes invasive pulmonary aspergillosis unlikely at that time — repeat if fever persists.
The classic misread
- Calling an air-crescent in a neutropenic patient an aspergilloma — it is angioinvasive disease at recovery.