Findings
Pulmonary presentations following exposure to Aspergillus sp.
have a variety of clinical and radiological manifestations.
The radiological manifestations actually are the consequences of the pathophysiological response to Aspergillus sp.,
which is linked closely to the patient's immune status.
Serious complications can be seen in immunocompromised patients. In this review,
we aim to provide common imaging findings to instigate clinically useful and appropriate management for those patients at risk of significant morbidity and mortality.
The radiologist plays a major role in the diagnosis of pulmonary Aspergillus infection.
When plain radiographic findings are subtle or equivocal,
CT has significant potential to allow identification of the accurate disease process in classical cases.
Although imaging findings in various types of pulmonary aspergillosis may be nonspecific,
in the appropriate clinical setting,
familiarity with the thin-section CT findings may suggest and even help establish the specific diagnosis.
Types:
- Non Invasive (Aspergilloma,
ABPA)
- Semi invasive (chronic necrotising)
Description:
1. Non-invasive:
Aspergilloma is characterized by a mass with soft-tissue attenuation. This is a fungal ball containing intertwined hyphae,
blood,
and inflammatory products,
formed by superinfection of a pre-existing lung cavity.
The mass is typically separated from the cavity wall by airspace (“air crescent” sign) and is often associated with thickening of the wall and adjacent pleura
An upper lobe predilection is common as cavity formation is frequently secondary to previous mycobacterial disease,
although pulmonary abscesses,
sarcoidosis,
bullae,
cystic lung disease,
or granulomatosis with polyangiitis are also predisposing factors.
Chest radiography will show the mycetoma as a single cavity containing a mobile mass associated with surrounding ‘air crescent’ sign
Allergic bronchopulmonary aspergillosis (ABPA) consists primarily of mucoid impaction and bronchiectasis involving predominantly the segmental and subsegmental bronchi of the upper lobes.
2.
Semi invasive or chronic necrotising type:
May manifest as an endobronchial mass,
obstructive pneumonitis or collapse,
or a hilar mass.
3.
Invasive:
Angioinvasive aspergillosis typically presents with nodules surrounded by a halo of ground-glass attenuation (“halo sign”) or pleural based,
wedge-shaped areas of consolidation.
4.
Other: Obstructing bronchopulmonary aspergillosis,
chronic cavitary and chronic fibrosing type pulmonary aspergillosis.